Pharmacological Attenuation of Endoplasmic Reticulum Stress Restores Sexual Behavior and Spermatogenesis in...

Di-(2-ethylhexyl)phthalate (DEHP) is a plasticizer commonly used in the manufacture of polyvinyl chloride (PVC) products in household items and medical devices. Recent evidence demonstrated the detrimental effects of DEHP on reproductive function. Endoplasmic reticulum (ER) stress and its associated cell death in testes play a critical role in the pathophysiology of DEHP-mediated reproductive toxicity. Considering this, the present study aimed to explore and validate the role of ER stress using 4-phenylbutyric acid (4-PBA), an ER stress inhibitor, in DEHP-mediated reproductive toxicity in male Wistar rats. Rats were divided into different experimental groups (n = 8) and treated with vehicle (corn oil, p.o.), DEHP (500 mg/kg; p.o.), DEHP + 4-PBA (500 mg/kg; p.o.), and DEHP + 4-PBA (1000 mg/kg; p.o.). DEHP and 4-PBA were administered in different experimental groups for 28 and 14 days, respectively. Results showed that DEHP exposure impaired the sexual and copulatory behavior of male rats. Biochemical analysis revealed that DEHP raised the oxidative-nitrosative stress markers along with depletion of GSH in testes. Scanning electron microscopy (SEM) analysis revealed sperm abnormalities and cellular anomalies in testicular ultrastructure in the DEHP-exposed group. In addition, histopathological examination found spermatogenesis anomalies and loss of germ cells in the DEHP-exposed group. At the molecular level, the expression of ER stress-associated proteins, such as GRP78, CHOP, and caspase-12, in DEHP-exposed testes highlights the role of ER stress. Furthermore, the impact of ER stress on DEHP-mediated reproductive deficits was further validated by the administration of 4-PBA. Results found that 4-PBA restored the sexual behavior, testicular anomalies, and testosterone level in DEHP-treated rats. In addition, 4-PBA suppressed DEHP-induced ER stress and associated cellular atrophy in the spermatogenesis process in testicular tissue. These findings concluded that ER stress plays an important role in DEHP-mediated reproductive toxicity, and 4-PBA shows the reproprotective effects via inhibiting the ER stress signaling pathway.