Neuroprotective effects of carboxymethylated chitosan on hydrogen peroxide induced apoptosis in Schwann cells

The protective and promotion effects of Carboxymethylated chitosan (CMCS) on peripheral nerve and cultured Schwann cells (SCs) have been demonstrated, but few studies discussed the protective roles of CMCS on SCs apoptosis. We explored the anti-apoptotic activities of CMCS in SCs to enhance cells survival in this present study. Rat SCs were isolated and cultured in vitro, hydrogen peroxide (H2O2) was used to establish the apoptosis models of SCs. Cells proliferative activity was assessed by CCK-8 assay. The apoptosis of SCs was detected by flow cytometry (FCM) analysis. Superoxide dismutase (SOD) and malondialdehyde (MDA) activities were detected by the corresponding assay kit. The nuclear appearance of apoptotic SCs was observed by nuclear staining with Hoechst 33342. The real-time PCR was performed to detect the levels of Bcl-2, Bax, Caspase-3 and -9 mRNA. Detection of caspase-3 and -9 was fulfilled by using Western blot analysis. FCM assay and Hoechst33342 staining results indicated that CMCS could protect SCs from apoptosis with dose and time-dependent manner. SOD and MDA analysis results indicated that CMCS could promote SOD activity and reduce the MDA levels in H2O2 induced SCs. The decreased caspase-3, -9 and Bax activities and increased Bcl-2 activity were observed in CMCS treated SCs. The present study indicates CMCS has the neuroprotective effect on peripheral nerves and inhibit SCs apoptosis.