# Pathophysiology and histological anomalies in testicular tissues of Calosoma olivieri exposed to heavy metals generated by pesticide industries

## TL;DR

This study shows how heavy metals from pesticide industries harm the testicular tissues of beetles, indicating environmental pollution.

## Contribution

The study introduces C. olivieri as a bioindicator for heavy metal pollution through detailed testicular tissue analysis.

## Key findings

- Heavy metal accumulation in testicular tissues caused significant enzyme inhibition and oxidative stress.
- Severe structural damage, including mitochondrial and nuclear destruction, was observed in polluted beetles.
- The findings suggest C. olivieri testicular anomalies can reliably indicate industrial heavy metal pollution.

## Abstract

Recently, there has been a critical demand for continuous investigations into environmental contamination with heavy metals to evaluate their detrimental impacts on different species inhabiting these contaminated areas. Therefore, we used Calosoma olivieri (Coleoptera, Carabidae) in the present study as a bioindicator for investigating pollution with heavy metals generated by pesticide industries in Kafr El-Zayat, Egypt. Toward this end, we probed the pathophysiological, histopathological, and ultrastructure anomalies of C. olivieri testicular tissues from the contaminated area in comparison to the clean site. Evaluation of heavy metal accumulation within testicular tissues was conducted employing energy-dispersive X-ray spectroscopy analysis. Furthermore, various biochemical parameters were measured to evaluate oxidative stress and the detoxification state of C. olivieri. Notably, significant inhibitions in antioxidant and detoxifying enzymes, including superoxide dismutase, catalase, glutathione S-transferase, glutathione peroxidase, reduced glutathione, and glutathione reductase, combined with elevated lipid peroxidation and protein carbonyl content were detected in testicular tissue of C. olivieri obtained from a polluted area due to the accumulation of multiple heavy metals. Additionally, severe structural aberrations were observed in the testicular tissues of C. olivieri obtained from the contaminated site compared to the control, including mitochondrial and nuclear destruction and deformed spermatogenic elements, along with obvious signs of tissue necrosis. Collectively, these results evinced impairment of male testicular tissues in beetles from the polluted location, which could serve as a reliable indicator of heavy-metal pollution in industrial areas.