Comparison of chronic administration of manganese oxide micro and nanoparticles on liver function parameters in male rats

Increased production and industrial application of manganese oxide (MnO2) nano and microparticles have led to increased human contact with these particles. In this study، the biodistribution of manganese in rat liver was studied after chronic administration of two MnO2 particles. Also، the effect of these particles was studied on body weight gain and liver function tests of rats. Male wistar rats were weighted and subcutaneously treated with 100 (μg/kg) nano- or micro-particles of MnO2 every two weeks for 14 weeks. Blood samples are taken directly from the heart of the rats (n=5) at the same times. The Mn level in samples of rat hepatic tissue was determined by ICP-MS. Serum levels of total protein، albumin، bilirubin، activities of transaminases، lactate dehdrogenase and alkaline phosphatase were measured by autoanalyzer. Rate of body weight gain in rats of nano group was significantly faster and in micro group rats was slower than control (p<0. 05). The hepatic Mn biodistribution، accumulation and bioclearance in nanoparticles group were different from microparticles group. The levels of total protein، albumin، bilirubin and alkaline phosphatase activity increased، while transaminease enzymes and lactate dehyrogenase activities decreased in serum of both groups (p<0. 05). The chronic administration of MnO2 nano- and microparticles casued manganese accumulation in hepatic tissue. The strong oxidizing property of both MnO2 particles and their binding with some hepatic enzymes can be main causes of liver dysfunction.