Methamphetamine Causes Photoreceptor Cell Damage Through Promoting Polarization of Macrophages and Inducing Inflammatory Response.

Classically activated macrophages (M1) are proinflammatory effectors and closely related to the progression of neurotoxicity. As a powerful psychostimulant and addictive drug, methamphetamine (Meth) abuse could result in long-lasting abnormalities in retina. This study investigated the effect of Meth at nontoxic concentration on macrophage activation state and its resultant toxicity to photoreceptor cells. Results showed that cytotoxicity was caused by Meth on 661 W cells after coculturing with RAW264.7 macrophage. RAW264.7 cells tended to switch to the M1 phenotype, releasing more proinflammatory cytokines after treatment with Meth. Meth could also upregulate the M1-related gene and protein expression. Our study demonstrated that Meth promoted macrophage polarization from M0 to M1 and induced inflammatory response, providing the scientific rationale for the photoreceptor cell damage caused by the Meth abuse.