Presence of nano-sized chitosan-layered silicate composites protects against toxicity induced by lead ions

Protecting cells from toxicosis even apoptosis induced by a variety of toxic heavy metals stimulus has drawn more and more attentions. This study was designed to elucidate whether chitosan-organic rectorite (CS-OREC) composites exhibited any protective effects on altered oxidative stress parameter in PC12 cells exposed to lead ions (Pb²⁺). The cells were exposed to Pb²⁺ either alone or in combination with CS-OREC composites for designated time to evaluate the efficacy of the composites on Pb²⁺-induced toxicity. The MTT assay results showed that the cell viability of PC12 was remarkably decreased when exposed to Pb²⁺, but significantly retained after adding CS-OREC composites compared to that of the control. The beneficial effect of CS-OREC composites on cytotoxicity was related, at least in part, to its ability to protect against apoptosis in PC12 cells exposed to 50μM Pb²⁺. Their protective effect was also associated with the inhibitory effect on Pb²⁺-induced activation of Bax/Bcl-2, P-38, and caspase-3 pathways, while was independent on JNK pathway.