Cadmium exposure induces testicular oxidative damage and histopathological changes in the freshwater leech Limnatis nilotica (Savigny, 1822): the protective role of salicylic acid

Abstract

The present study examined the histopathological changes and some parameters of oxidative stress in the testes of the freshwater leech Limnatis nilotica, following their exposure to 50 µg l⁻¹ of cadmium (Cd). The protective effects of salicylic acid (SA) in mitigating Cd-induced oxidative and histopathological injury were also investigated. We found that Cd exposure caused several histopathological changes in leech testes, such as vacuolisation of spermatogenic cysts which were strongly destroyed and disorganised. Biochemical study showed oxidative stress damage marked by a substantial increase in malondialdehyde and hydrogen peroxidase levels as well as disturbance in the activity of the leech antioxidant system. Interestingly, the testes from the Cd and SA leech-exposed group exhibited increased enzymatic and nonenzymatic antioxidant mechanism defenses, including superoxide dismutase, catalase, glutathione peroxidase, glutathione, oxidized glutathione, thiols, and ascorbic acid, in comparison with the testes of leeches exposed to Cd alone. Thus, SA supplementation considerably attenuated the histopathological lesions induced by Cd exposure, thereby restoring the normal appearance of the testes. In summary, the findings of this study indicate that SA treatment ameliorated the testicular histopathological and oxidative stress-induced damages caused by exposure to Cd through enhancing the antioxidant defense system.

Keywords:

• aquatic toxicity
• cadmium
• leech
• oxidative stress
• testis