Antitumour activity and side effects of combined treatment with chitosan and cisplatin in sarcoma 180-bearing mice

Applications of Chitosan and its Derivatives in Skin and Soft Tissue Diseases

Chitosan and its derivatives are bioactive molecules that have recently been used in various fields, especially in the medical field. The antibacterial, antitumor, and immunomodulatory properties of chitosan have been extensively studied. Chitosan can be used as a drug-delivery carrier in the form of hydrogels, sponges, microspheres, nanoparticles, and thin films to treat diseases, especially those of the skin and soft tissue such as injuries and lesions of the skin, muscles, blood vessels, and nerves. Chitosan can prevent and also treat soft tissue diseases by exerting diverse biological effects such as antibacterial, antitumor, antioxidant, and tissue regeneration effects. Owing to its antitumor properties, chitosan can be used as a targeted therapy to treat soft tissue tumors. Moreover, owing to its antibacterial and antioxidant properties, chitosan can be used in the prevention and treatment of soft tissue infections. Chitosan can stop the bleeding of open wounds by promoting platelet agglutination. It can also promote the regeneration of soft tissues such as the skin, muscles, and nerves. Drug-delivery carriers containing chitosan can be used as wound dressings to promote wound healing. This review summarizes the structure and biological characteristics of chitosan and its derivatives. The recent breakthroughs and future trends of chitosan and its derivatives in therapeutic effects and drug delivery functions including anti-infection, promotion of wound healing, tissue regeneration and anticancer on soft tissue diseases are elaborated.

Protective effects of water-soluble low-molecular-weight β-(1,3-1,6)D-glucan purified from Aureobasidium pullulans GM-NH-1A1 against UFT toxicity in mice

Objectives

5-Fluorouracil and its derivatives are widely used in the treatment of a variety of tumours. However, their use is associated with gastrointestinal toxicity, myelotoxicity and immune toxicity. In this study, we examined the protective effects of low-molecular-weight β-glucan isolated from Aureobasidium pullulans GM-NH-1A1 against toxicity of UFT (combination of tegafur (1-(2-tetrahydrofuryl)-5-fluorouracil) and uracil) in mice bearing colon 26 tumours.

Methods

UFT was administered orally at 50 mg/kg once daily for 14 days alone or with orally administered low-molecular-weight β-glucan, 25, 50 and 100 mg/kg twice daily.

Key findings

Tumour growth was inhibited equally in all treatment groups. Onset of diarrhoea, which started on day 9 of UFT administration, was delayed by concomitant administration of the β-glucan (50 and 100 mg/kg twice daily). Histological analysis showed that damage to small-intestine villi by UFT was inhibited by the orally administered β-glucan.

Conclusions

Oral administration of low-molecular-weight β-glucan prevents gastrointestinal mucositis associated with UFT therapy without interfering with its anti-tumour activity.

Effects of Fungal-derived High Molecular Weight Chitosan on 5-Fluorouracil-induced Adverse Reactions

The effects of fungal-derived high molecular weight chitosan (HMWC) on the prevention of 5-fluorouracil (5-FU)-induced side-effects were studied in a sarcoma-bearing mice model. 5-FU (12.5mg/kg) was gargled into the mice with or without HMWC (25, 75, and 150mg/kg) every 12 h for consecutive 8 or 16 days in different experiments. The HMWC (25—150 mg/kg) exerted no toxicity and did not interfere with the anti-tumor activity of 5-FU on sarcoma-bearing mice. HMWC in a higher dose (150 mg/kg) partially protected 5-FU-induced cytotoxicity on peripheral leukocytes, lymphocytes, and bone marrow CD-19 positive cells. HMWC reversed the 5-FU suppression of intestine sucrase activity and attenuated the 5-FU-induced diarrhea. Bone marrow cells micronucleus and DNA comet assays demonstrated that HMWC significantly reversed 5-FU-induced genome toxicity to marrow cells. These results suggested that fungal-derived HMWC attenuated the 5-FU-induced bone marrow and gastrointestinal toxicity, and has the potential for clinical applications in the future.

Low molecular weight chitosan inhibits obesity induced by feeding a high-fat diet long-term in mice

Three low molecular weight chitosans (molecular weight: 21, 46 and 130 kDa) obtained by enzymatic hydrolysis of a high molecular weight chitosan (average molecular weight: 650 kDa) had low viscosity and were water-soluble. The effects of these water-soluble chitosans on pancreatic lipase (in-vitro) and the elevation of plasma triacylglycerol concentration after the oral lipid tolerance test were examined in mice. The water-soluble 46-kDa chitosan was the most effective at inhibiting pancreatic lipase activity (in-vitro) and plasma triacylglycerol elevation after the oral lipid tolerance test. Based on this result, the effects of the 46-kDa chitosan on increases in bodyweight, various white adipose tissue weights, and plasma and liver lipids were examined in mice fed a high-fat diet for 20 weeks. Water-soluble 46-kDa chitosan (300 mg kg(-1), twice daily) prevented increases in bodyweight, various white adipose tissue weights and liver lipids (cholesterol and triacylglycerol) in mice fed a high-fat diet, and further increased the faecal bile acid and fat. The results suggest that the lipid-lowering effects of the 46-kDa chitosan may be mediated by increases in faecal fat and/or bile acid excretion resulting from the binding of bile acids, and by a decrease in the absorption of dietary lipids (triacylglycerol and cholesterol) from the small intestine as a result of the inhibition of pancreatic lipase activity. Water-soluble 46-kDa chitosan (100 and 300 mg kg(-1), twice daily) did not cause liver damage with the elevation of glutamic oxaloacetic transaminase and glutamic pyruvic transaminase, or kidney damage with the elevation of blood nitrogen urea. It was concluded that water-soluble 46-kDa chitosan is a safe functional food.

Antitumor effects of various low-molecular-weight chitosans are due to increased natural killer activity of intestinal intraepithelial lymphocytes in sarcoma 180-bearing mice

Various low-molecular-weight chitosans such as the 21-kDa, 46-kDa, and 120-kDa chitosans obtained by enzymatic hydrolysis of a high-molecular-weight chitosan (average molecular weight, 650 kDa) had low viscosity and were water soluble. We examined the antitumor activity of various water-soluble chitosans with different molecular weights in sarcoma 180-bearing mice. A 21-kDa water-soluble chitosan and oligochitosan (100 and 300 mg/kg body) administered by i.g. intubation reduced the tumor growth and final tumor weight in sarcoma 180-bearing mice. A 46-kDa water-soluble chitosan at a dose of 100 mg/kg body reduced the tumor growth and final tumor weight, but had no effect at 300 mg/kg. On the other hand, a 130-kDa water-soluble chitosan had no effect on tumor growth. The 21- and 46-kDa chitosans (10 mg/L) enhanced the natural killer (NK) activity in intestinal intraepithelial lymphocytes (IELs) or splenic lymphocytes. The NK activity of low-molecular-weight chitosan (21- and 46-kDa chitosans)-treated IELs or splenic lymphocytes was stronger than that of high-molecular-weight chitosan (130- and 650-kDa chitosans)-treated IELs or splenic lymphocytes. In addition, low-molecular-weight chitosan-treated IELs or splenic lymphocytes also enhanced the cytotoxic activity against sarcoma 180 cells. In an in vivo study, although low-molecular-weight chitosan-treated IELs had cytotoxic activity against tumor cells, splenic lymphocytes treated with chitosans had no effect. These findings suggest that the antitumor activity of low-molecular-weight chitosans (12- and 46-kDa chitosans) and oligochitosan might be due in part to the enhancement of NK activity in IELs. Thus, the low-molecular-weight chitosans or oligochitosan might be useful in preventing tumor growth through the activation of intestinal immune functions.

Antitumour activity and adverse reactions of combined treatment with chitosan and doxorubicin in tumour-bearing mice

We examined the antitumour activity and adverse reactions, such as myelotoxicity, gastrointestinal toxicity and body-weight loss,of the cancer chemotherapy drug doxorubicin when given with chitosan in sarcoma 180-bearing mice. Intraperitoneally administered doxorubicin (5 mg kg(-1)) given on days 1 and 8 with or without orally administered chitosan (200, 400 and 800 mg kg(-1) twice daily) inhibited tumour growth. The orally administered chitosan (400 and 800 mg kg(-1) twice daily) prevented doxorubicin-induced body-weight loss and small-intestinal mucosal injury. Similarly, the reduction of leucocyte number induced by the intraperitoneally administered doxorubicin was restored to normal by the oral administration of chitosan (400 and 800 mg kg(-1) twice daily). It seems likely that the mechanisms by which the orally administered chitosan protects against doxorubicin-induced gastrointestinal toxicity may be due to the formation of doxorubicin-chitosan complex in the small-intestinal mucosa through the diffusion of chitosan into the small-intestinal villi. In conclusion, our data suggest that the oral administration of chitosan prevents the gastrointestinal mucositis associated with doxorubicin therapy.