Early-Life Exposure to DBP and DEHP Induces Ultrastructural Testicular Damage and Semen Quality Deterioration Through Modulation of Inhibin- α , Calretinin, and PPAR- γ

Abstract

Phthalates, including dibutyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP), are plasticizers causing male reproductive toxicity. This study investigated early pubertal exposure in ninety-six immature male Swiss albino mice administered DBP or DEHP (100, 200, and 400 mg/kg) for 15 days, evaluated at 36, 45, 50, and 70 days to assess both exposure effects and recovery. Light microscopy of Hematoxylin and Eosin-stained sperm smears and transmission electron microscopy (TEM), alongside immunohistochemical investigations for inhibin-α, calretinin, and peroxisome proliferator-activated receptor gamma (PPAR-γ), were utilized. Exposure induced severe, dose-dependent toxicity, causing complete sperm absence at 36 days, followed by reduced viability (∼20%) and teratozoospermia (>80%). TEM revealed extensive ultrastructural damage; mitochondrial degeneration reached 37% (DBP-400) and 47.9% (DEHP-400), while Sertoli cell vacuolization averaged ∼8 and ∼5 vacuoles/cell in high-dose groups. Concurrently, disrupted lipid homeostasis was evidenced by peroxisome proliferation and increased Leydig lipid area fraction, exceeding 50% in the DBP-400 group by 50 days. Recovery at 70 days was dose-dependent, occurring primarily in low-dose groups following treatment withdrawal. Immunohistochemical investigations demonstrated decreased inhibin-α and calretinin expression, alongside increased PPAR-γ immunoreactivity. Early-puberty phthalate exposure was associated with mitochondrial injury, altered PPAR-γ expression, disrupted lipid homeostasis, and incomplete recovery of testicular alterations at higher doses.