Histopathology of feral fish from a PCB-contaminated freshwater lake

The purpose of this study was to evaluate the potential toxic effects of chronic sublethal polychlorinated biphenyl (PCB) exposure on feral fish, using histopathology as an endpoint. Histopathological study of bream (Abramis brama) and asp (Aspius aspius) living in a PCB-polluted freshwater lake revealed abnormal cellular changes in the renal corpuscle of both species. Dilation of glomerular capillaries (DGC), mesangial edema (ME), an adhesion between visceral and parietal layers of Bowman's capsule (ABC), and filling of Bowman's space (FBS), were highly prevalent features in lake fish. The prevalence of each of these lesions was significantly lower, or totally absent in fish caught from reference locations. Cellular alterations in liver, gill, gonads, spleen, and intestine were all linked to seasonal changes. The results suggest that some of the observed histopathological changes in renal glomeruli, particularly DGC and ME, could possibly indicate a prolonged chemical stress caused by PCBs and related compounds. It is also possible that chronic PCB exposure may have suppressed and weakened the immuno systems of exposed fish making them more vulnerable to secondary parasitic infections.