Insight into nano chitosan effects on MC3T3-E1 cell growth / 中国组织工程研究

ABSTRACT

BACKGROUND:Acute toxicity in vivo experiments in previous studies has been confirmed that the median lethal dose of chitosan microcapsules is higher than 2 000 mg/kg, but the specific pathogenic mechanism is unclear. OBJECTIVE:To explore the influence of nano chitosan on MC3T3-E1 cellgrowth as a bone substitute material, as wel as the physiological function of rats. METHODS:MC3T3-E1 cells were respectively cultured in Dulbecco’s modified Eagle’s medium with different concentrations of chitosan nanoparticles (0, 10 mg/L, 100 mg/L, 1 g/L, 10 g/L). The absorbance values were determined. Changes in MC3T3-E1 cellmorphology were observed by scanning electron microscope after 24 hours culture. 10 g/L nano chitosan suspension was prepared using PBS. Two different doses of nano chitosan suspension (166.67 and 16.67 mg/kg body weight) with PBS were injected intraperitoneal y into Sprague-Dawley rats, three times a week, for 4 weeks. The control group was injected with equal volume of physiologic saline. Serum biochemical markers were detected to analyze the functions of liver and kidney of rats. Moreover, histopathology slices were observed to evaluate the morphological changes of tissue and inflammatory infiltration. RESULTS AND CONCLUSION:10 mg/L, 100 mg/L, 1 g/L, 10 g/L nano chitosan suspensions were found growth inhibition in MC3T3-E1 cells as compared with the control group (P<0.05). The reunion of chitosan was observed in the cytoplasm of MC3T3-E1 cells by transmission electron microscopy. On the cellsurface, pseudopodia formed, wavy undulating membrane, nucleus degeneration, fragmentation and condensation were found. Compared with the control group, blood urea nitrogen, Na+levels were significantly increased in rats injected with nano chitosan suspension at two dosages, but the K+level in the high concentration group was decreased significantly (P<0.05). cellapoptosis was found in the liver and renal tissue in a dose-dependent manner. It suggests that apoptosis may be the possible mechanism of nano chitosan toxicity, and normal physiological function may be impacted over a certain dose.