In Vitro Cytotoxicity Of Polyaniline Nanomaterial To Macrophage And Related Mechanisms

Since21st century, with the increasingly use of nanomaterial, its security has also drawn people’s attention. This thesis aims at exploring the toxic effect of nano-structured polyaniline (PANI) to rat original generation abdominal macrophage and the related mechanism.Polyaniline nanomaterial was prepared by the rapid surface polymerization process. The rat original generation abdominal macrophage was used to investigate the toxicity of nano-PANI. We would observe cytotoxicity by MTT assay in24-72h after administration of PANI. Moreover, the damage effect to cells was analyzed according to the exposure of cellular reactive oxygen species level (ROS) and the change of mitochondrial membrane potential, and Hoechst staining was observed in macrophages apoptosis. We used Western Blot for detection of apoptosis related protein caspase-8, caspase-9, caspase-3and their activation. RT-PCR was also executed to detect the mRNA expression level of caspase-3, Bcl-2and Bax.The experimental results showed that, after stimulation of24-72h, nano-PANI at the levels of0.1μg/ml and1μg/ml had no significant effect on macrophage survival rate, while apoptosis was induced by the10and100μg/ml of PANI. An elevated ROS level and mitochondrial membrane potential loss was also observed. In Western Blot detection, caspase-9and caspase-8protein expression level had no significant difference compared to the control, and neither of their activated patterns were detected, but caspase-3protein expressed slightly more than the control group, its activated form appeared this trend, too.Based on all the experiment, we speculated that the uptake of nao-PANI might lead to a less level of Bcl-2and a higher level of Bax, then a lower Bcl-2/Bax ratio would increase mitochondrial membrane permeability, which results in a detection of mitochondrial membrane potential. Higher ROS level would be the following one. Inducers released from mitochondrial peroxide product would activate caspase-3, the activated caspase-3could shear DNA with a result of nucleic acid fracture fragments, ultimately leading to cell death.