| PURPOSE:The purpose of this investigation was to study the biological safety of carboxymethyl chitosan zinc and peptide,in order to provide a reference for the materials' security.METHODS:1.The cytotoxicity: The primary cells were obtained from human periodontal tissues and cultured.The cultured cells were identified by observing the shape under microscope and by immunocytochemical method.HPDLCs were cultured in different concentrations of the tested materials extract and the activity of cells was evaluated using CCK-8 assay.The cytotoxicity grade was determined in term of the cell relative growth rates.The concentration of the tested materials extract was 100%,75%,50%,25% in group 1~4.The fifth group had no materials.2.The acute toxicity: 20 wistar-rats were divided into experimental group and control group randomly.The rats in experimental group were given 5 g/kg tested materials with intragastric administration once,while control group's were given equal normal saline.Observing the rats' activity for one week before they were collected blood and death.Hematology,blood biochemistry,body weight,organ index and pathologic biopsy were checked.3.Oral mucosa irritation: 10 wistar-rats were smeared tested materials on the left oral mucosa and normal saline on the other said for 5 min after they were anesthetized.The oral mucosa where was in the tested part were cutted after 24 h for pathologic biopsy.4.The acute skin irritation: 10 wistar-rats were get rid of back hair about 3 cm multiply by 5 cm before the test began.The tested materials were smeared on the skin and were fixed by hypo-allergenic adhesive for 24 h.The rats and their skin were observed for one week.5.The chronic toxicity: 40 wistar-rats were divided into high-dose group(5g/kg,n=10),middle-dose group(2g/kg,n=10),low-dose group(0.5g/kg,n=10)and control group(nomal saline,n=10)randomly.Each rat was received tested materials by intragastric sdministration(qd)for continuous three months.Hematology,blood biochemistry,body weight,organ index and pathologic biopsy were checked.6.All statistical analysis was performed using SPSS 17.0 software package.RESULTS:1.The cytotoxicity: The primary cells owned fibroblasts' shape.Immunocytochemical analysis showed the cells were stained positively to antibodies against vimentin,and negatively to antibodies against cytokeratin,which indicated that they were external embryo mesenchymal cell.The cell relative growth rates were more than 100%,no matter the concentrations of materials extract were.The cytotoxicity grade of CMC-Zn+-P was 0.2.The acute toxicity: After a single gavage,all rats in two groups were in good condition.There were no death of rats and no significant differences between the two groups in hematology,blood biochemistry,body weight and organ index.The results of pathology biopsy had no obvious abnormalities.3.Oral mucosa irritation: The results did not appear death of rats or congestion,edema,erosion in oral mucosa.4.The acute skin irritation: There was no congestion,edema or erosion in rats' skin.No rat died in the test.5.The chronic toxicity: There was no significant difference among groups in body weight,organ index,hematology or obvious abnormalities in pathology biopsy.During the serum biochemical tests,there was no abnormalities in AST?ALT?BUN?GLU and CREA.Among groups,only the total cholesterol was different.The content of the high-dose group was higher than the control group(P<0.001),the middle-dose group and the low-dose group(P=0.015,0.001).The content of the middle-dose group was higher than the control group(P=0.003).CONCLUSIONS:CMC-Zn+-P showed no cytotoxicity to HPDLCs in vitro and it could promote the cells' proliferation.There was no acute toxicity,no oral mucosa irritation,no acute skin irritation or chronic toxicity to wistar-rats. |
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