The renal histology and ultrastructure in rats given methylmercury and ethanol in combination

The effects of combined administration of methylmercury (MeHg) and ethanol (EtOH) on renal morphology were examined in the rat. Forty-eight male Wistar rats were divided into 6 groups of 8 rats each as follows: group 1 was given feed ad libitum with no treatment; group 2 was restricted to 70 mL of feed daily with no treatment; groups 3-6 were restricted to 70 mL of feed daily and gavaged with distilled water, MeHg alone, EtOH alone, or MeHg in combination with EtOH, respectively, daily for 45 days. The ingestion of MeHg and EtOH in combination caused severe structural renal lesions which involved the glomerulus and all segments of the uriniferous tubule. Only with this combination treatment (group 6) was glomerular pathology observed; accumulations of platelets and inflammatory cells, fibrosis and thickening of the mesangium were observed in the glomerulus. There was also severe tubulointerstitial nephritis characterized by tubular atrophy, accumulation of inflammatory cells especially neutrophils, and increased collagen deposition in the same group. In contrast, the ingestion of either MeHg or EtOH produced less severe lesions mainly in the proximal tubular epithelium. This study suggests that EtOH enhanced the nephrotoxicity of MeHg.