Synergistic Testicular Toxicity Induced by Arsenic and Microplastics and Its Attenuation by Imperatorin in Wistar Rats

Environmental exposure to xenobiotics is being increasingly implicated in the global decline in male reproductive health. Arsenic is a well-known environmental toxicant associated with impaired spermatogenesis and endocrine disruption. Microplastics have recently emerged as pervasive pollutants capable of interacting with co-existing contaminants and modifying their effects. However, the reproductive effect of combined arsenic and microplastic exposure remains unclear. This study investigated the effects of co-exposure to arsenic and microplastics on male reproductive parameters and evaluated the potential protective role of imperatorin.

Adult male Wistar rats were divided into five experimental groups (n = 6 per group): G1—control; G2—arsenic; G3—microplastics; G4—arsenic + microplastics; and G5—arsenic + microplastics + imperatorin. Epididymal sperm samples were analysed for sperm concentration, motility, and morphological abnormalities. Testicular tissues were examined using haematoxylin and eosin staining, Perl’s Prussian blue staining to evaluate iron deposition, and caspase-3 immunohistochemistry to assess apoptotic activity.

Individual exposure to arsenic or microplastics produced moderate alterations in sperm parameters and testicular histology compared with controls. Combined exposure resulted in the most pronounced reproductive toxicity. Sperm analysis showed reductions in sperm concentration and motility with increased morphological abnormalities such as coiled or fractured tails and head–tail separation. Histopathological examination revealed severe disruption of seminiferous tubule architecture, degeneration of the germinal epithelium, and reduced spermatogenic cell layers. Perl’s Prussian blue staining demonstrated increased iron deposition within testicular tissue, indicating altered iron homeostasis and oxidative imbalance. Caspase-3 immunohistochemistry showed strong apoptotic signalling in the seminiferous epithelium of the co-exposed group. Treatment with imperatorin improved sperm parameters, preserved seminiferous tubule structure, reduced iron accumulation, and decreased caspase-3 immunoreactivity.

Microplastics intensify arsenic-induced reproductive toxicity, highlighting their role in mixture effects of environmental xenobiotics. Imperatorin mitigates these changes, indicating its potential as a protective agent against environmentally induced reproductive toxicity.