Food emulsifier glycerin monostearate aggravates phthalates’ testicular toxicity by disrupting tight junctions’ barrier function in rats

Objectives This study was aimed to investigate the effect of widely used food emulsifier glycerin monostearate (GM) on testicular toxicity caused by the mixture of three commonly used PEs (MPEs) in rats, and further to explore the underlying mechanism. Materials and Methods Thirty male Sprague-Dawley rats were divided into three groups randomly. Rats were orally treated with 160 mg/kg/d MPEs in MPEs group; Rats were coinstantaneously treated with 160 mg/kg/d MPEs and 200 mg/kg/d GM in MPEs+GM group; Rats were treated with the excipient in control group. The intervention last for 5 weeks. Testis weight, epididymis weight, testicular histopathology and serum testosterone were detected for testicular toxicity evaluation. The testicular ultrastructure, the tight junction proteins zonula occluden (ZO)-1 and claudin were measured for the mechanism exploration. Results The body weight, epididymis, serum testosterone level, and anogenital distance in MPEs+GM group were significantly decreased comparing with control group (P<0.05); Testicular histopathological observation showed that shed spermatids were observed in MPEs+GM group. Ultrastructural observation of testicular cells showed that the cristae number was decreased in some mitochondrion in MPEs group, whereas the cristae was fused and disappeared in most mitochondrion in MPEs+GM group. The tight junctions were broken in MPEs+GM group, meanwhile, the expression of ZO-1 and claudin were altered in MPEs+GM group (P<0.01). Conclusions The results from this study indicated that GM aggravated MPEs’ testicular toxicity, which might relate to the injured mitochondrion and damaged tight junctions in testicular tissue.