Global effects of subchronic treatment of microcystin-LR on rat splenetic protein levels

Microcystin-LR (MCLR), released by toxic cyanobacterial blooms, has received worldwide concerns in the past decades for its hepatotoxicity. Recent studies show that microcystins (MCs) can be accumulated in immune organs and exert notable immunotoxicity. In order to better understand cellular responses in immune tissues disrupted by MCLR treatment, this work mainly focuses on the spleen impairments of rats. After a subchronic 50 d exposure (1 or 10 mu g/kg body weight per day), spleen index, MCLR accumulation, histological change and plasma lysozyme activity were detected in MCLR-treated rat. Results indicated that prolonged exposure of MCLR led to toxin accumulation and caused severe damage in spleen of rats, and eventually impaired the immune functions. To further our understanding of the toxic effects of MCLR on the spleen and the mechanisms behind it, a proteomic analysis was performed to determine the global effects of MCLR on splenetic protein levels. In total, 48 proteins were identified and showed a significant increase or decrease in abundance compared to the control after MCLR exposure. These proteins are mainly involved in immune response, oxidative stress, energetic metabolism and the cytoskeleton assembly, indicating that MCLR exerts complex toxic effects in rat spleen and jointly results in immunotoxicity. (C) 2012 Elsevier B.V. All rights reserved.