[The effect of carboxymethyl chitosan zinc and peptide on IL-1,TNF-α and PGE-2 in gingival crevicular fluid of miniature pigs].

PURPOSE: This experiment was aimed at exploring whether carboxymethyl chitosan zinc and peptide （CMC-Zn(+)-P） can reduce the occurrence and development of periodontal tissue inflammation effectively by observing the change of IL-1,TNF-α and PGE-2 level in gingival crevicular fluid （GCF） before and after brushing, so as to find a new effective material in preventing and treating periodontal diseases. METHODS: Miniature pigs were selected as experimental subjects and divided into 4 groups randomly: the control group; CMC-Zn(+)-P group (material group);brushing group; brushing + CMC-Zn(+)-P group (composite group). Gingival crevicular fluid before and one month after the experiment was collected. The levels of IL-1, TNF-α and PGE-2 were examined by enzyme-linked immune-sorbent assay, while the clinical periodontal index was recorded. SPSS 18.0 software package was used for statistical analysis. RESULTS: There was no significant difference in levels of IL-1, TNF-α and PGE-2 and clinical periodontal index between the 4 groups before experiment. After one month, the levels of IL-1, TNF-α, PGE-2 in GCF had significant difference between 4 groups. The levels of IL-1, TNF-α, PGE-2 in composite group were significant lower than that of the other three groups (P<0.008).The levels of IL-1, TNF-α and PGE-2 in the material group and brushing group were significantly lower than that of the control group (P<0.008). Compared with materials group, the brushing group had significantly lower level of IL-1,significantly higher level of PGE-2 ,but no difference in the level of TNF-α.In addition, the teeth calculus index of composite group was significantly lower than that of other groups (P<0.05). CONCLUSIONS: CMC-Zn(+)-P can effectively reduce periodontal tissue inflammation and cut down the speed of deposition of dental calculus. If used cooperatively with brushing, the effect will be better.

Antidiabetic effects of chitooligosaccharides on pancreatic islet cells in streptozotocin-induced diabetic rats.

AIM: To investigate the effect of chitooligosaccharides on proliferation of pancreatic islet cells, release of insulin and 2 h plasma glucose in streptozotocin-induced diabetic rats. METHODS: In vitro, the effect of chitooligosaccharides on proliferation of pancreatic islet cells and release of insulin was detected with optical microscopy, colorimetric assay, and radioimmunoassay respectively. In vivo, the general clinical symptoms, 2 h plasma glucose, urine glucose, oral glucose tolerance were examined after sixty days of feeding study to determine the effect of chitooligosaccharides in streptozotocin-induced diabetic rats. RESULTS: Chitooligosaccharides could effectively accelerate the proliferation of pancreatic islet cells. Chitooligosaccharides (100 mg/L) had direct and prominent effect on pancreastic beta cells and insulin release from islet cells. All concentrations of chitooligosaccharides could improve the general clinical symptoms of diabetic rats, decrease the 2 h plasma glucose and urine glucose, and normalize the disorders of glucose tolerance. CONCLUSION: Chitooligosaccharides possess various biological activities and can be used in the treatment of diabetes mellitus.

Antitumor activities of D-glucosamine and its derivatives.

The growth inhibitory effects of D-glucosamine hydrochloride (GlcNH(2).HCl), D-glucosamine (GlcNH(2)) and N-acetyl glucosamine (NAG) on human hepatoma SMMC-7721 cells in vitro were investigated. The results showed that GlcNH(2).HCl and GlcNH(2) resulted in a concentration-dependent reduction in hepatoma cell growth as measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. This effect was accompanied by a marked increase in the proportion of S cells as analyzed by flow cytometry. In addition, human hepatoma SMMC-7721 cells treated with GlcNH(2).HCl resulted in the induction of apoptosis as assayed qualitatively by agarose gel electrophoresis. NAG could not inhibit the proliferation of SMMC-7721 cells. GlcNH(2).HCl exhibited antitumor activity against Sarcoma 180 in Kunming mice at dosage of 125-500 mg/kg, dose of 250 mg/kg being the best. GlcNH(2).HCl at dose of 250 mg/kg could enhance significantly the thymus index, and spleen index and could promote T lymphocyte proliferation induced by ConA. The antitumor effect of GlcNH(2).HCl is probably host-mediated and cytocidal.

A polypeptide from Chlamys farreri abolishes UV-induced apoptosis in murine thymocytes in vitro.

Previously we reported that a polypeptide from Chlamys farreri (PCF) was a potent photoprotective agent against ultraviolet (UV) irradiation in vitro. To understand the mechanism by which PCF protects cells from irradiation, we studied anti-apoptotic effects of PCF against UV irradiation on the murine thymocytes in vitro. MTT and flow cytometric analysis assays showed that 2h pretreatment with PCF completely abolished UV induced cell death. TEM examination showed that PCF fully protected the ultrastructure of thymocytes exposed to UV irradiation. Lipid peroxidation and intracellular reactive oxygen species assays indicated that PCF efficiently blocked production of reactive oxygen intermediates induced by UV irradiation. Further, PCF protected UV-irradiated thymocytes from losing mitochondrial transmembrane potential and DNA fragmentation. Based on these observations we propose that PCF is a potent anti-apoptotic factor, which protects cells from irradiation at multiple steps.

[Lead expelling effect of carboxymethyl chitosan calcium in lead poisoned mice].

OBJECTIVE: To observe the effects of carboxymethyl chitosan calcium (CCC) on concentration of lead, calcium and zinc, and the liver antioxidative capacity in lead poisoned mice. METHODS: Mice were randomly divided into 7 groups, including normal group, calcium carbonate group, lead-model group, and three experimental groups treated with CCC in three different doses, and the CaNa2EDTA positive control group. The lead poisoned mice model was established by giving water contained with lead acetate. CCC was administrated to mice i.g. once a day. Thirty days later, mice were killed and the concentrations of lead, calcium and zinc in blood, liver, brain and femur were determined by atomic absorption spectrophotometer. Maleic dialdehyde (MDA), total antioxidative capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities in liver were measured by using assay kit. RESULTS: CCC significantly reduced the concentration of lead in blood, brain, liver and femur from about 1.56 microg/g, 13.38 microg/g, 16.15 microg/g, 1011.62 microg/g to about 0.50 microg/g, 5.57microg/g, 5.64 microg/g, 457.86 microg/g, and markedly increased the concentration of calcium in femur in lead poisoned mice. CCC had no significant side-effects on concentration of zinc in lead poisoned mice. The antioxidative profile was favorably changed as manifested by decreasing the level of MDA, increasing the activities of SOD, GSH-Px and T-AOC in livers of the in lead poisoned mice. CONCLUSION: CCC might significantly advance the excretion of lead, increase the concentration of calcium in femur and the antioxidative capacity in lead-loaded mice.

The effect of carboxymethyl-chitosan on proliferation and collagen secretion of normal and keloid skin fibroblasts.

In this study, different molecular weight CM-chitosans were prepared and the effects on the growth and collagen secretion of normal skin fibroblasts and keloid fibroblasts were investigated in vitro. CM-chitosan promoted the proliferation of the normal skin fibroblast significantly but inhibited the proliferation of keloid fibroblast. The higher CM-chitosan concentration had a higher initial effect and the lower CM-chitosan concentration had a longer affecting time to the normal skin fibroblast. The lower molecular weight CM-chitosan had significant twofold activities. The CM-chitosan could reduce the ratio of type I/III collagen in keloid fibroblast by inhibiting the secretion of collagen type I; and had no effect on the secretion of types I and III collagen in the normal skin fibroblast.