Effects of cadmium exposure on testis apoptosis in the marine teleost Gobius niger

Abstract

It is known that heavy metals can accumulate in tissues during aquatic organism growth (bioaccumulation) and often biomagnify up the food chain interfering with the health and reproduction of both wildlife and humans. Recently, cadmium (Cd) was included in the endocrine disruptors list, exerting its effect on gametes quality and reproductive functions; in addition, its role as apoptotic factor was evidenced in different cell types and tissues. In the present study, the effects of two different Cd doses on testis and liver of the black goby Gobius niger were analyzed. Cd concentration in the water and its uptake by the gills were measured by differential pulse anodic stripping voltammetry. Toxic, apoptotic, and stressor Cd effects were analyzed using metallothionein (MTT), caspase 3 and heath shock protein 70 (HSP70), respectively, as bioindicators. The results of the present study suggested that, in the gills, the saturation of all specific metal sites was reached only with the highest Cd dose exposure. Either testis and liver showed an increase of MTT gene expression and protein synthesis in addition to HSP70 gene expression, related with Cd concentration in the water indicating that both tissues were affected by Cd exposure. In conclusion, the present study, not only shows the toxic effect of Cd on hepatic tissue, but also indicates its potency as apoptotic factor in the testis. This is supported by the increase of caspase 3 gene expression and the presence of its active form in testis of exposed fish.