Research ArticleExperimental Studies

Therapeutic Effects of GGsTop® Gel in a Mouse Model of 5-Fluorouracil-induced Oral Mucositis With Reduced White Blood Cells

ISSEI TAKEUCHI, KATSUYA TANAKA and KIMIKO MAKINO
Anticancer Research September 2021, 41 (9) 4313-4319; DOI: https://doi.org/10.21873/anticanres.15236

Abstract

Background/Aim: In order to produce an animal model for oral mucositis induced by anticancer drugs, it is necessary to maintain an immunosuppressive state. We determined the optimal dose and frequency of 5-fluorouracil for a model mouse production. In addition, we used this model to investigate the effect of GGsTop® gelation on the therapeutic effect of oral mucositis. Materials and Methods: Changes in body weight and white blood cell count were measured to determine the optimal dosing schedule. The therapeutic effect of GGsTop® gel using chitosan was evaluated by observing changes in the ulcer area for three weeks and measuring collagen and glutathione concentrations in oral mucosal tissue. Results: The optimal dose and frequency of 5-fluorouracil were found to be 50 mg/kg every four days. It was revealed that the therapeutic effect of GGsTop® was enhanced by gelation. Conclusion: GGsTop® gel is suggested to be a promising formulation for the treatment of oral mucositis.

Key Words:

Recently, GGsTop® (2-amino-4{[3-(carboxymethyl)phenyl] (methyl)phosphono}butanoic acid) has been studied as a novel therapeutic agent for oral mucositis which occurs in cancer treatment. The study, using a mouse model of 5-fluorouracil (5-FU)-induced oral mucositis, showed that this potent and selective γ-glutamyl transpeptidase inhibitor (1) has a therapeutic effect on oral mucositis and does not affect white blood cell (WBC) count (2). In a study using a rat model for quantitative experiments, GGsTop® promoted collagen production. In addition, the measurement results of glutathione concentration showed that it alleviated oxidative stress conditions (3). These reports suggest that GGsTop® is effective in treating cancer chemotherapy-induced oral mucositis. Model animals of 5-FU-induced oral mucositis used in these studies were produced by injecting acetic acid into the oral mucosa. Animals were immunosuppressed by intraperitoneal administration of 5-FU. Since the purpose of this method was to produce oral mucositis that was clear in shape and lasted for 2 weeks, we considered that these model animals were completed by administration of acetic acid. However, in actual cancer chemotherapy, medication is continued even after the onset of oral mucositis. It is necessary to develop an animal model on which oral mucositis therapeutic experiments can be performed while maintaining the immunosuppressive state caused by anticancer drugs.

Oral mucositis, one of the most common side-effects of cancer chemotherapy and radiation therapy, is a common and significant clinical problem in oncology (4). It often affects patient quality of life (4) and anticancer therapy compliance (5). While an efficient treatment method is required, water-soluble GGsTop® is only dissolved in ultrapure water (6) or physiological saline (7) and administered as an aqueous solution, and research on its dosage form has not progressed. Gel and film formulations are typical dosage forms that target the oral mucosa. Various types of gel preparations such as hydrogel, oleogel, and bigel were reported as topical delivery systems applicable to oral mucosa (8). In film formulations, mucosal adherent buccal films have been proposed as a topical drug delivery system that can provide efficient therapeutic delivery (9). Rebamipide-containing film for oral mucositis induced by cancer chemotherapy was reported (10).

In this study, we planned to develop a new mouse model for cancer chemotherapy-induced oral mucositis in which 5-FU was continuously administered after acetic acid administration. The dose and frequency of 5-FU were determined by changes in body weight and white blood cell count, and mortality rate. We also developed a gel containing GGsTop® using chitosan (CS), Pluronic® F-127 (PF-127), and hydroxypropyl methylcellulose (HPMC). CS was used to improve the mucosal adhesion of the gel and slowly release the contained drug. Chitosan was used to improve the mucoadhesive properties of the gel (11) and to achieve sustained drug release (12). PF-127 was used to increase the mucoadhesive properties of CS (13). HPMC was used as a film-forming polymer (10). The therapeutic effect of the GGsTop® gel was evaluated by changes in WBC count and ulcer area, observation of oral mucosal tissue (2), and quantitative measurements of collagen and glutathione in the tissue using the new mouse model, as in our previous studies (3).

Materials and Methods

Materials. 5-FU (C4H3FN2O2, purity >98.5%), HPMC, and lactic acid (CH3CH(OH)COOH, purity ≥85.0%) were purchased from Fujifilm Wako Pure Chemical Corp. (Osaka, Japan). Isoflurane for the animal was purchased from Mylan Inc. (Pittsburgh, PA, USA). Medetomidine hydrochloride (Domitol®), which is an alpha 2 adrenoceptor agonist, was purchased from Nippon Zenyaku Kogyo Co., Ltd. (Koriyama, Japan). Midazolam, which is a benzodiazepine derivative, was purchased from Teva Takeda Pharma Ltd. (Nagoya, Japan). Butorphanol tartrate (Vetorphale®) was purchased from Meiji Seika Pharma Co., Ltd. (Tokyo, Japan). 5-Sulfosalicylic acid dihydrate (C6H3(OH)(SO3H)COOH·2H2O, purity >99.0%) was purchased from Kanto Chemical Co., Inc. (Tokyo, Japan). GGsTop® was kindly donated by Nahls. Co., Ltd. (Kyoto, Japan). CS (low molecular weight) and PF-127 were purchased from Sigma-Aldrich Co. LLC. (St. Louis, MO, USA). Other chemicals were of the highest reagent grade commercially available.

Dosage and frequency of 5-FU for the preparation of a mouse model with oral mucositis. Nine-week-old male ICR mice were purchased from Japan SLC Inc. (Tokyo Japan). All animal care was conducted under the Guidelines for Animal Experimentation of Tokyo University of Science, which are based on the Guidelines for Animal Experimentation of the Japanese Association for Laboratory Animal Science. Mice were housed in stainless-steel cages under standard environmental conditions (23±1°C, 55%±5% humidity and a 12/12 h light/dark cycle) and maintained with free access to water and a standard laboratory diet (carbohydrates 30%; proteins 22%; lipids 12%; vitamins 3%) ad libitum (Nihon Nosan Kogyo Co., Yokohama, Japan).

Similarly to our previous studies, 5-FU was used to replicate the immunosuppression induced by the anticancer drugs (2, 3, 14, 15). The 5-FU solution (8 mg/ml) was prepared by dissolving 360 mg of 5-FU in 45 ml of normal saline. On days 0, 2, and 4 of the experiment, mice were administered the 5-FU solution by intraperitoneal injection at a dose of 50 mg/kg body weight under isoflurane anesthesia. After day 4, the mice were divided into four groups: a group receiving 25 mg/kg every two days (25 mg/kg-2D), a group receiving 25 mg/kg every four days (25 mg/kg-4D), a group receiving 50 mg/kg every two days (50 mg/kg-2D), and a group receiving 50 mg/kg every four days (50 mg/kg-4D), and 5-FU administration was continued. As a control group, healthy mice were used. The optimal 5-FU dose and frequency were determined by examining changes in body weight and WBC count, and mortality.

A new mouse model of 5-FU-induced oral mucositis was produced using 5-FU and acetic acid aqueous solution. 5-FU was administered to mice at the dose and frequency determined above. Five days after the start of the test (the day after three doses of 50 mg/kg of 5-FU), the mice were anesthetized by intraperitoneal administration of a combination of anesthetics, which was prepared with 0.3 mg/kg of medetomidine hydrochloride, 4.0 mg/kg of midazolam, and 5.0 mg/kg of butorphanol, under isoflurane anesthesia (16), and then 15.0 μl of 20% acetic acid aqueous solution was injected into the right buccal mucosa. In a therapeutic study using this mouse model and the GGsTop® gel, the day of acetic acid administration was set as a new “day 0”.

Preparation of GGsTop® gel for the treatment of oral mucositis. A CS gel was prepared by dissolving 2.1 g of CS and 0.9 g of PF-127 in 100 ml of a 3% (w/v) lactic acid solution at 70°C. HPMC gel was prepared by dissolving 3.0 g of HPMC in 100 ml of purified water at 4°C. A CS-HPMC gel was prepared by mixing the CS gel and the HPMC gel in a ratio of 2: 1. The GGsTop® gel was prepared by mixing equal amounts of CS-HPMC gel and 10 μg/ml GGsTop® aqueous solution.

In vitro release tests were performed to investigate the release behavior of GGsTop® from the GGsTop® gel using the dialysis membrane method (17). The cumulative release of GGsTop® was expressed as the ratio of GGsTop® released from the GGsTop® gel to the amount of GGsTop® initially contained in the gel. Five milliliters of the GGsTop® gel were placed in a dialysis tube (18) and added to 95.0 ml of phosphate-buffered saline (PBS, pH 7.4). The sample was shaken at 170 stroke/min at 37°C. After 5, 10, 15, 30, and 60 min, 990 μl of the external solution was collected. Amounts of GGsTop® in the sample solutions were determined using high-performance liquid chromatography (HPLC, Shimadzu Corp., Kyoto, Japan) with a reversed-phase column (CAPCELL PAK C18 S5, size: 4.6×150 mm, Osaka Soda Co., Ltd., Osaka, Japan). After adding 10 μl of acetic acid. The mobile phase consisted of a 1.0% acetic acid aqueous solution and acetonitrile with a volume ratio of 9:1. HPLC measurements were carried out at 40°C (flow rate: 1.0 ml/min), and 20 μl of sample solution was applied. The measurement results were compared with the results of 5 μg/ml GGsTop® aqueous solution.

Therapeutic effect of GGsTop® gel in the treatment of oral mucositis. From day 1, 5 μg/ml GGsTop® aqueous solution and 5 μg/ml GGsTop® gel were applied to the ulcer of the buccal mucosa of mice once a day under the combination of anesthetics. After the administration, the mice were allowed to sleep for several hours until the effects of anesthesia ceased. WBC counts were measured on days -5, -3, -1, 0, 3, 7, 11, 15, and 19 of the treatment experiment. Ulcer area measurements were performed on days -5, - 3, -1, 0, 3, 7, 11, 15, and 19 using an image analysis software (Image J, National Institutes of Health, Bethesda, MD, USA) (11, 15, 19). The results were compared to the group without treatment and the group in which CS-HPMC gel (GGsTop® concentration: 0 μg/ml) alone was applied to the ulcer.

Effect of GGsTop® gel on collagen in oral mucosal tissues. To evaluate the effect of GGsTop® gel on collagen production, on days 3, 7, and 12 of the treatment, the oral mucosal tissues of the model mouse were observed and the amount of collagen in the tissue was quantitatively measured. Similar to our previous studies (2, 3), preparation of frozen tissue sections was performed based on the method of Kawamoto (20); the obtained tissue sections were compared after staining collagen using a collagen stain kit (K-61, Collagen Research Center, Kiyose, Japan) which stains collagen and non-collagen proteins as red and green, respectively. Staining and quantification of collagen were performed based on the instruction manual of the kit. After staining, observation of tissue sections was performed using a fluorescence microscope (BZ-9000, Keyence Corp., Osaka, Japan). The stained sample was treated with the extract included in the kit, and then the amount of collagen was measured using an ultraviolet-visible spectrophotometer (UV-2450, Shimadzu Corp.). As a control group, normal and healthy mice were used.

Effect of GGsTop® gel on GSH and GSSG in oral mucosal tissues. Glutathione normally exists in the reduced form (GSH) in the body, and GSH is converted into an oxidized form (GSSG: glutathione disulfide) by stimulation, such as oxidative stress (3). To investigate the effect of GGsTop® gel on oxidative stress, GSH and GSSG concentrations in oral mucosal tissue of the model mouse were measured. On days 3 and 12 of the treatment experiment, GSH and GSSG in the tissues were quantified using GSSG/GSH quantification kit (G257, Dojindo Laboratories, Mashiki, Japan) (3). The quantitative measurement was performed based on the instruction manual of the kit. 5-sulfosalicylic acid dihydrate was used as an aqueous solution. As a control group, normal and healthy mice were used.

Results

Preparation of a mouse model with oral mucositis. Figure 1 shows changes in body weight and WBC count. The body weight change in Figure 1 was expressed as the ratio of the body weight of the mouse on each day to the body weight of the mouse on day 0 of the 5-FU administration experiment. As shown in Figure 1A, there was a tendency to gain weight in the control and 25 mg/kg-4D groups. In groups of 25 mg/kg-2D and 50 mg/kg-4D, body weight decreased from day 12, and there was a significant difference in body weight change on day 16 compared to the control group. In the 50 mg/kg-2D group, body weight decreased from day 8. On day 16, mice were euthanized by isoflurane because the body weight change of mice decreased to 86.4±3.0%. As shown in Figure 1B, in all four 5-FU-administrated groups, similar reductions in WBC counts occurred until day 4. On days 8-16, it was shown that the WBC count changed depending on the dose and frequency of 5-FU. Mice death was confirmed in groups of 25 mg/kg-2D and 50 mg/kg-2D to which 5-FU was administered every two days. Mortality rates in groups of 25 mg/kg-2D and 50 mg/kg-2D were 16.7% and 66.6%, respectively.

Figure 1.
Figure 1.

Changes in body weight (A) and WBC count (B) in a group receiving 25 mg/kg of 5-FU every two days (25 mg/kg-2D), a group receiving 25 mg/kg every four days (25 mg/kg-4D), a group receiving 50 mg/kg every two days (50 mg/kg-2D), and a group receiving 50 mg/kg every four days (50 mg/kg-4D). As a control group, healthy mice were used (mean±S.D., n=3, *p<0.05, **p<0.01, Tukey’s test).

In vitro release of GGsTop® from the GGsTop® gel. Figure 2 shows the results of in vitro release tests. It was confirmed that gelation significantly reduced the amount of GGsTop® that permeated the dialysis membrane. Gelation reduced the cumulative release of GGsTop® by 62.5% at 5 min and 46.2% at 60 min.

Figure 2.
Figure 2.

Cumulative release of GGsTop® from GGsTop® gel using the dialysis membrane method (mean±S.D., n=3, **p<0.01, Tukey’s test). GGsTop® solution was measured for comparison.

Therapeutic effect of GGsTop® gel in the treatment of oral mucositis. Figure 3 shows changes in WBC count and ulcer area of oral mucositis. As shown in Figure 3A, there was no significant difference in the change in WBC count between the four groups. The GGsTop® gel-treated group (GGsTop® gel group) had a significantly smaller ulcer area on days 3-11 compared to the no-treatment group. The time required for ulcer disappearance was 21, 19, 15, and 19 days in the no-treatment group, GGsTop® solution-treated group (GGsTop® solution group), GGsTop® gel group, and CS-HPMC gel-treated group (CS-HPMC gel group), respectively.

Figure 3.
Figure 3.

Changes in the WBC count (A) and ulcer area (B) in the group without treatment (no-treatment), GGsTop® solution-treated group (GGsTop® solution), GGsTop® gel-treated group (GGsTop® gel), and CS-HPMC gel-treated group (CS-HPMC gel) (mean±S.D., n=3, *p<0.05, **p<0.01, Tukey’s test).

Images of collagen-stained oral mucosal sections are shown in Figure 4, and the collagen concentrations in the tissues are shown in Figure 5. As shown in Figure 4, It was confirmed that the tissue on the mucosal surface was destroyed on day 3 immediately after the ulcer occurred. After Day 7, recovery of epithelial tissue was confirmed in all treated groups compared to the no-treatment group. In the GGsTop® gel group, an increase in collagen and densification of the subcutaneous tissue were confirmed compared to the other groups. As shown in Figure 5, collagen concentration in oral mucosal tissue tended to be higher in the GGsTop® gel group. On day 12, the concentrations of the no-treatment group, GGsTop® solution group, GGsTop® gel group, and CS-HPMC gel group recovered to 0.64, 0.60, 0.98, and 0.77 times, respectively, of that of the control group.

Figure 4.
Figure 4.

Collagen-stained oral mucosal tissues in the group without treatment (no-treatment), GGsTop® solution-treated group (GGsTop® solution), GGsTop® gel-treated group (GGsTop® gel), and CS-HPMC gel-treated group (CS-HPMC gel). Healthy mice were used as a control group. Collagen and non-collagen proteins were stained red and green, respectively.

Figure 5.
Figure 5.

Changes in collagen concentration in oral mucosal tissues in the group without treatment (no-treatment), GGsTop® solution-treated group (GGsTop® solution), GGsTop® gel-treated group (GGsTop® gel), and CS-HPMC gel-treated group (CS-HPMC gel). Healthy mice were used as a control group (mean±S.D., n=3, *p<0.05, **p<0.01, Tukey’s test).

Figure 6 and Figure 7 show the quantitative results of glutathione on days 3 and 12, respectively, as GSSG and GSH concentrations. The GSSG concentration was 64.4-70.0 μmol/l on day 3 and 66.3-71.6 μmol/l on day 12, showing no significant difference between all groups. On day 3, GSH concentration was significantly lower than that of the control group due to the occurrence of oral mucositis. On day 12, the concentrations of the no-treatment group, GGsTop® solution group, GGsTop® gel group, and CS-HPMC gel group were 0.67, 0.86, 1.16, and 0.71 times higher than that of the control group, respectively.

Figure 6.
Figure 6.

Changes in GSH and GSSG concentrations in oral mucosal tissues in a group without treatment (no-treatment), GGsTop® solution-treated group (GGsTop® solution), GGsTop® gel-treated group (GGsTop® gel), and CS-HPMC gel-treated group (CS-HPMC gel) on day 3. Healthy mice were used as a control group (mean±S.D., n=3, **p<0.01, Tukey’s test).

Figure 7.
Figure 7.

Changes in GSH and GSSG concentrations in oral mucosal tissues in a group without treatment (no-treatment), GGsTop® solution-treated group (GGsTop® solution), GGsTop® gel-treated group (GGsTop® gel), and CS-HPMC gel-treated group (CS-HPMC gel) on day 12. Healthy mice were used as a control group (mean±S.D., n=3, *p<0.05, Tukey’s test).

Discussion

5-FU is well known to induce intestinal mucositis with severe diarrhea (21, 22), which causes anorexia, dehydration, and various systemic toxicities to cause weight loss (23). Therefore, we considered that the dose and frequency of 5-FU in the group in which immunosuppressive status was maintained and body weight loss was confirmed, were appropriate for the production of a mouse model of 5-FU-induced oral mucositis. The 25 mg/kg-4D group was unsuitable because changes in WBC count suggested that it had escaped from the immunosuppressive state. The 25 mg/kg-2D group, the 50 mg/kg-2D group, and the 50 mg/kg-4D group maintained relatively low WBC counts. From these results, we selected the dose and frequency of 5-FU used in the 50 mg/kg-4D group for the model mouse production because it was the most immunosuppressed group in which the mice did not die.

The results of the therapeutic study using the mouse model of 5-FU-induced oral mucositis suggested that improvement of sustained release and mucosal adhesion due to gelation of GGsTop® contributed to the therapeutic effect. CS-HPMC gel showed the same therapeutic effect as GGsTop® solution. CS and its derivatives have been studied as antibacterial agents against various fungi, bacteria, and viruses (24, 25). They have also been used as materials for wound dressings (26). We assumed that this result reflected the low retention of GGsTop® solution in the ulcer site, the protective effect of the CS-HPMC gel on the ulcer site, and the antibacterial activity derived from CS. Therefore, to improve the effect of GGsTop® gel, it was suggested that it is important to study the gel as base material, and CS is one of the promising materials.

Conclusion

In this study, we produced a novel 5-FU-induced oral mucositis model mouse. Compared to the conventional model, this model has the advantage of reproducing the immunosuppressive state caused by anticancer drugs. Hence, it is useful as a model of oral mucositis that occurs in cancer chemotherapy and is expected to contribute to the development of therapeutic agents. In addition, in the therapeutic study using the mouse model, it was shown that the therapeutic effect is improved by using GGsTop® as a gel preparation. Further research is required for the practical application of GGsTop® preparation, such as examination of the optimum gel composition, comparison with other dosage forms, and establishment of an appropriate administration method.

Acknowledgements

The Authors are grateful to NAHLS. Co., Ltd (Kyoto, Japan) for providing GGsTop®. The Authors are grateful for the suggestions given by Dr. Y. Shimamura from Tokyo University of Science.

Footnotes

  • Authors’ Contributions

    Takeuchi and K. Tanaka designed the study and wrote the initial draft of the manuscript. K. Makino contributed to the analysis and interpretation of data and assisted in the preparation of the manuscript. All Authors approved the final version of the manuscript and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Conflicts of Interest

    The Authors declare that they have no potential conflicts of interest regarding this study.

  • Received June 9, 2021.
  • Revision received July 20, 2021.
  • Accepted July 21, 2021.

References

  1. ↵
    1. Watanabe B,
    2. Morikita T,
    3. Tabuchi Y,
    4. Kobayashi R,
    5. Li C,
    6. Yamamoto M,
    7. Koeduka T and
    8. Hiratake J
    : An improved synthesis of the potent and selective γ-glutamyl transpeptidase inhibitor GGsTop together with an inhibitory activity evaluation of its potential hydrolysis products. Tetrahedron Letters 58(38): 3700-3703, 2021. DOI: 10.1016/j.tetlet.2017.08.019
    OpenUrlCrossRef
  2. ↵
    1. Shimamura Y,
    2. Takeuchi I,
    3. Terada H and
    4. Makino K
    : Therapeutic effect of GGsTop, selective Gamma-glutamyl transpeptidase inhibitor, on a mouse model of 5-Fluorouracil-induced oral mucositis. Anticancer Res 39(1): 201-206, 2019. PMID: 30591459. DOI: 10.21873/anticanres.13098
    OpenUrlAbstract/FREE Full Text
  3. ↵
    1. Takeuchi I,
    2. Kawamata R and
    3. Makino K
    : Effects of GGsTop® on collagen and glutathione in the oral mucosa using a rat model of 5-fluorouracil-induced oral mucositis. In Vivo 35(1): 175-180, 2021. PMID: 33402464. DOI: 10.21873/invivo.12246
    OpenUrlAbstract/FREE Full Text
  4. ↵
    1. Al-Ansari S,
    2. Zecha JA,
    3. Barasch A,
    4. de Lange J,
    5. Rozema FR and
    6. Raber-Durlacher JE
    : Oral mucositis induced by anticancer therapies. Curr Oral Health Rep 2(4): 202-211, 2015. PMID: 26523246. DOI: 10.1007/s40496-015-0069-4
    OpenUrlCrossRefPubMed
  5. ↵
    1. Cinausero M,
    2. Aprile G,
    3. Ermacora P,
    4. Basile D,
    5. Vitale MG,
    6. Fanotto V,
    7. Parisi G,
    8. Calvetti L and
    9. Sonis ST
    : New frontiers in the pathobiology and treatment of cancer regimen-related mucosal injury. Front Pharmacol 8: 354, 2017. PMID: 28642709. DOI: 10.3389/fphar.2017.00354
    OpenUrlCrossRefPubMed
  6. ↵
    1. Koyama T,
    2. Tsubota A,
    3. Sawano T,
    4. Tawa M,
    5. Watanabe B,
    6. Hiratake J,
    7. Nakagawa K,
    8. Matsumura Y and
    9. Ohkita M
    : Involvement of γ-Glutamyl transpeptidase in ischemia/reperfusion-induced cardiac dysfunction in isolated rat hearts. Biol Pharm Bull 42(11): 1947-1952, 2019. PMID: 31685777. DOI: 10.1248/bpb.b19-00434
    OpenUrlCrossRefPubMed
  7. ↵
    1. Kubota R,
    2. Hayashi N,
    3. Kinoshita K,
    4. Saito T,
    5. Ozaki K,
    6. Ueda Y,
    7. Tsuchishima M,
    8. Tsutsumi M and
    9. George J
    : Inhibition of γ-glutamyltransferase ameliorates ischaemia-reoxygenation tissue damage in rats with hepatic steatosis. Br J Pharmacol 177(22): 5195-5207, 2020. PMID: 32910829. DOI: 10.1111/bph.15258
    OpenUrlCrossRefPubMed
  8. ↵
    1. Wróblewska M,
    2. Szymańska E,
    3. Szekalska M and
    4. Winnicka K
    : Different types of gel carriers as metronidazole delivery systems to the oral mucosa. Polymers (Basel) 12(3): 680, 2020. PMID: 32204334. DOI: 10.3390/polym12030680
    OpenUrlCrossRefPubMed
  9. ↵
    1. Di Prima G,
    2. Conigliaro A and
    3. De Caro V
    : Mucoadhesive polymeric films to enhance barbaloin penetration into buccal mucosa: a novel approach to chemoprevention. AAPS PharmSciTech 20(1): 18, 2019. PMID: 30603884. DOI: 10.1208/s12249-018-1202-1
    OpenUrlCrossRefPubMed
  10. ↵
    1. Takeuchi I,
    2. Togo C and
    3. Makino K
    : Rebamipide-containing film using chitosan and HPMC for oral mucositis induced by cancer chemotherapy. Anticancer Res 39(12): 6531-6536, 2019. PMID: 31810918. DOI: 10.21873/anticanres.13868
    OpenUrlAbstract/FREE Full Text
  11. ↵
    1. Takeuchi I,
    2. Kamiki Y and
    3. Makino K
    : Therapeutic efficacy of rebamipide-loaded PLGA nanoparticles coated with chitosan in a mouse model for oral mucositis induced by cancer chemotherapy. Colloids Surf B Biointerfaces 167: 468-473, 2018. PMID: 29723818. DOI: 10.1016/j.colsurfb.2018.04.047
    OpenUrlCrossRefPubMed
  12. ↵
    1. Miyazaki S,
    2. Ishii K and
    3. Nadai T
    : The use of chitin and chitosan as drug carriers. Chem Pharm Bull (Tokyo) 29(10): 3067-3069, 1981. PMID: 7318032. DOI: 10.1248/cpb.29.3067
    OpenUrlCrossRefPubMed
  13. ↵
    1. Cafaggi S,
    2. Leardi R,
    3. Parodi B,
    4. Caviglioli G,
    5. Russo E and
    6. Bignardi G
    : Preparation and evaluation of a chitosan salt-poloxamer 407 based matrix for buccal drug delivery. J Control Release 102(1): 159-169, 2005. PMID: 15653142. DOI: 10.1016/j.jconrel.2004.09.019
    OpenUrlCrossRefPubMed
  14. ↵
    1. Shimamura Y,
    2. Takeuchi I,
    3. Terada H and
    4. Makino K
    : A mouse model for oral mucositis induced by cancer chemotherapy. Anticancer Res 38(1): 307-312, 2018. PMID: 29277788. DOI: 10.21873/anticanres.12223
    OpenUrlAbstract/FREE Full Text
  15. ↵
    1. Takeuchi I,
    2. Kawamata R and
    3. Makino K
    : A rat model of oral mucositis induced by cancer chemotherapy for quantitative experiments. Anticancer Res 40(5): 2701-2706, 2020. PMID: 32366415. DOI: 10.21873/anticanres.14241
    OpenUrlAbstract/FREE Full Text
  16. ↵
    1. Kawai S,
    2. Takagi Y,
    3. Kaneko S and
    4. Kurosawa T
    : Effect of three types of mixed anesthetic agents alternate to ketamine in mice. Exp Anim 60(5): 481-487, 2011. PMID: 22041285. DOI: 10.1538/expanim.60.481
    OpenUrlCrossRefPubMed
  17. ↵
    1. Mittal G,
    2. Sahana DK,
    3. Bhardwaj V and
    4. Ravi Kumar MN
    : Estradiol loaded PLGA nanoparticles for oral administration: effect of polymer molecular weight and copolymer composition on release behavior in vitro and in vivo. J Control Release 119(1): 77-85, 2007. PMID: 17349712. DOI: 10.1016/j.jconrel.2007.01.016
    OpenUrlCrossRefPubMed
  18. ↵
    1. Takeuchi I,
    2. Suzuki T and
    3. Makino K
    : Skin permeability and transdermal delivery route of 50-nm indomethacin-loaded PLGA nanoparticles. Colloids Surf B Biointerfaces 159: 312-317, 2017. PMID: 28858661. DOI: 10.1016/j.colsurfb.2017.08.003
    OpenUrlCrossRefPubMed
  19. ↵
    1. Shimamura Y,
    2. Takeuchi I,
    3. Terada H and
    4. Makino K
    : A mouse model for oral mucositis induced by cancer chemotherapy. Anticancer Res 38(1): 307-312, 2018. PMID: 29277788. DOI: 10.21873/anticanres.12223
    OpenUrlAbstract/FREE Full Text
  20. ↵
    1. Kawamoto T
    : Use of a new adhesive film for the preparation of multi-purpose fresh-frozen sections from hard tissues, whole-animals, insects and plants. Arch Histol Cytol 66(2): 123-143, 2003. PMID: 12846553. DOI: 10.1679/aohc.66.123
    OpenUrlCrossRefPubMed
  21. ↵
    1. Wadler S,
    2. Benson AB 3rd.,
    3. Engelking C,
    4. Catalano R,
    5. Field M,
    6. Kornblau SM,
    7. Mitchell E,
    8. Rubin J,
    9. Trotta P and
    10. Vokes E
    : Recommended guidelines for the treatment of chemotherapy-induced diarrhea. J Clin Oncol 16(9): 3169-3178, 1998. PMID: 9738589. DOI: 10.1200/JCO.1998.16.9.3169
    OpenUrlAbstract/FREE Full Text
  22. ↵
    1. Benson AB 3rd.,
    2. Ajani JA,
    3. Catalano RB,
    4. Engelking C,
    5. Kornblau SM,
    6. Martenson JA Jr.,
    7. McCallum R,
    8. Mitchell EP,
    9. O’Dorisio TM,
    10. Vokes EE and
    11. Wadler S
    : Recommended guidelines for the treatment of cancer treatment-induced diarrhea. J Clin Oncol 22(14): 2918-2926, 2004. PMID: 15254061. DOI: 10.1200/JCO.2004.04.132
    OpenUrlAbstract/FREE Full Text
  23. ↵
    1. Sano T,
    2. Utsumi D,
    3. Amagase K,
    4. Matsumoto K,
    5. Tominaga M,
    6. Higuchi K,
    7. Takeuchi T and
    8. Kato S
    : Lafutidine, a histamine H2 receptor antagonist with mucosal protective properties, attenuates 5-fluorouracil-induced intestinal mucositis in mice through activation of extrinsic primary afferent neurons. J Physiol Pharmacol 68(1): 79-90, 2017. PMID: 28456772.
    OpenUrlPubMed
  24. ↵
    1. Chirkov SN
    : [The antiviral activity of chitosan (review)]. Prikl Biokhim Mikrobiol 38(1): 5-13, 2002. PMID: 11852567.
    OpenUrlPubMed
  25. ↵
    1. Raafat D,
    2. von Bargen K,
    3. Haas A and
    4. Sahl HG
    : Insights into the mode of action of chitosan as an antibacterial compound. Appl Environ Microbiol 74(12): 3764-3773, 2008. PMID: 18456858. DOI: 10.1128/AEM.00453-08
    OpenUrlAbstract/FREE Full Text
  26. ↵
    1. Rossi S,
    2. Marciello M,
    3. Sandri G,
    4. Ferrari F,
    5. Bonferoni MC,
    6. Papetti A,
    7. Caramella C,
    8. Dacarro C and
    9. Grisoli P
    : Wound dressings based on chitosans and hyaluronic acid for the release of chlorhexidine diacetate in skin ulcer therapy. Pharm Dev Technol 12(4): 415-422, 2007. PMID: 17763146. DOI: 10.1080/10837450701366903
    OpenUrlCrossRefPubMed
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Therapeutic Effects of GGsTop® Gel in a Mouse Model of 5-Fluorouracil-induced Oral Mucositis With Reduced White Blood Cells
ISSEI TAKEUCHI, KATSUYA TANAKA, KIMIKO MAKINO
Anticancer Research Sep 2021, 41 (9) 4313-4319; DOI: 10.21873/anticanres.15236
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