Microplastic Exposure Impairs Weight Gain, Reproduction, Blood Glucose Levels, and Organ Health in Rats (Rattus norvegicus)

Background: Emerging studies highlight growing concerns about the effects of microplastics on mammals, however further studies are needed to fully understand their health impacts. This study investigated the effects of microplastics on rats (Rattus norvegicus). Methods: Thirty rats were divided randomly into five groups, each consisting of six animals. Group 1 served as the negative control, while Group 2 (positive control) was administered 10% lead acetate. Test rats in Groups 3, 4, and 5 were orally exposed to 1%, 5%, and 10% microplastic solutions, respectively. Over a 28-day period, the rats' body weights, blood glucose levels, reproductive performance, offspring survival rates, and mortality rates were monitored. Thereafter, the livers and kidneys of the rats were harvested for histopathological analysis. Results: Rats dosed with 5% and 10% microplastics experienced weight increases of 4.73% and 4.06%, respectively, which were significantly lower (p < 0.05) than the 8.29% increase in the negative control group. Moreover, the 1%, 5%, and 10% groups had glucose increases of 30.17%, 38.09%, and 40.00%, respectively, which were significantly higher than the 16.00% increase observed in the negative control group. The negative control group had 15 offspring per birth, of which 12 survived; the 1% group had 13 offspring, of which 10 survived; the 5% group recorded 11 offspring and 6 survivors; and the 10% group recorded 9 offspring and 4 survivors. Histopathological examination revealed dose-dependent inflammation and necrosis in the kidneys and livers of exposed rats. Conclusion: These findings indicate that microplastics exhibit toxic effects, emphasizing the need for strategies to reduce human exposure to these particles.