Early exposure to deltamethrin deteriorates testicular and post-testicular sperm maturation events in rats

Objective: To explore the effects of deltamethrin exposure during prepubertal stage on male reproductive parameters in rats. Methods: Forty male Wistar rats, aged 23 postnatal days, were randomly divided into four groups of ten rats each. The control group received tap water, while the vehicle control group was administered with 1 mL of peanut oil. Experimental groups received deltamethrin 3 mg/kg and 6 mg/kg, respectively. All treatments were administered orally. At postnatal day 91, all the rats were sacrificed to assess the histology of testes and serum testosterone levels. We also evaluated the binding of deltamethrin to 3β-hydroxysteroid dehydrogenase (HSD), a key enzyme involved in steroidogenesis, using in silico docking and molecular dynamics simulations to assess the stability and binding energy of the 3β-HSD and deltamethrin complex over 100 ns time frame. Results: Deltamethrin-exposed rats showed significant weight loss, followed by a marked reduction in serum testosterone levels. They also demonstrated the suppression of testicular steroidogenic enzymes like 3β-HSD and 17β-HSD levels, which were accompanied by sperm morphological abnormalities when compared with the control group rats. Moreover, molecular docking studies indicated that deltamethrin interacts with 3β-HSD competitively with pregnenolone which may be the reason for impaired steroidogenesis. Conclusions: Early life exposure to deltamethrin may induce reproductive toxicity at adult stage. Further exploration studies are warranted to record conclusive evidence for the effects of deltamethrin early exposure.