BTEX induces histopathological alterations, oxidative stress response and DNA damage in the testis of the freshwater leech Erpobdella johanssoni (Johansson, 1927)

Abstract

The widespread application of the hydrocarbons benzene, toluene, ethylbenzene and xylene (BTEX) has led to their consideration as major aquatic environmental pollutants, and exposure to these hydrocarbons has become a serious concern given their detrimental health effects on aquatic species. We investigated in the present study the impact of chronic exposure to BTEX on the testis of the freshwater leech Erpobdella johanssoni. The results revealed that BTEX induced severe histological alterations revealed by vacuolar degeneration in the spermatogenic cysts, and a complete loss of normal cysts was observed. The cytophore was grossly destroyed, and extensive necrosis and detached germ cells from cytophore were observed. Interestingly, BTEX exposure induced a significant increase in malondialdehyde (MDA) levels by 85.71% in the testicular tissue of treated leeches compared to the control (P < 0.00005), whereas the activity levels of SOD, GPx and CAT antioxidant biomarkers were significantly decreased by 60%, 81.81% and 47.5%, respectively. Additionally, using the alkaline comet assay, we observed that BTEX exposure induced significant DNA fragmentation in the testis cells of treated leeches compared to controls (P < 0.00005). Overall, this study unravels the histopathologic, oxidative stress and DNA damage induced by BTEX on the testis of the freshwater leech E. johanssoni.

Keywords

• BTEX
• Aquatic toxicity
• Testis
• Oxidative stress
• DNA damage
• Leech