Abstract:

Objective: To investigate the effects of low molecular weight chitosan (LMCTS) on the expression of chcoride channel 3(CIC-3) in cardiomyocytes of the rats with hypoxia-reoxygenation(H/R)injury,and to probe the protective effect of LMCTS on the myocardial H/R injury and its correlation with the expression of ClC-3. Methods: The cardiomyocytes of rats were cultured and divided into blank control group,model group,and 200,400 and 600 mg·L^-1 LMCTS groups.The cells in blank control group were cultured regularly without any treatment;and the cells in other groups were treated under hypobaric and hypoxic condition for 1 h,then they got reoxygenation at 37℃ for 24 h to establish the cardiomyocyte H/R injury models.The cells in model group were cultured regularly without drugs and the cells in three different concentrations of LMCTS groups were given 200,400 and 600 mg·L^-1 LMCTS before establishing the H/R injury models.The ClC-3 mRNA expression level in cardiomyocytes of the rats was detected by RT-PCR method;the relative expression level ClC-3 protein in cardiomyocytes of the rats was detected by Western blotting method and immunofluorescence method. Results: The Western blotting and RT-PCR results indicated that the expression levels of ClC-3 mRNA and protein in cardiomyocytes of the rats in model group were higher than those in blank control group (P<0.01);but the expression levels in different concentrations of LMCTS groups were lower than those in model group(P<0.05),especially in 600 mg·L^-1 LMCTS group.The immunofluorescence experiment results showed that compared with blank control group,the fluorescence intensities in cardiomyocytes of the rats in model group were increased,but the fluorescence intensities in different concentrations of LMCTS groups were lower than that in model group. Conclusion: The ClC-3 expression in cardiomyocytes of the rats associates with the cardiomyocyte H/R injuriy.LMCTS could decrease the ClC-3 expression level and protect the cardiomyocytes away from H/R injury by the down-regulation of ClC-3 expression level.

Key words: chitosan, cardiomyocytes, hypoxia, reoxygenation, chloride channel 3