Protective effect of Lycium barbarum polysaccharide on reproductive system injury of female rats induced by 2,4-dichlorophenoxyacetic acid

[Background] 2,4-Dichlorophenoxyacetic acid (2,4-D) is widely used as a broad-leaved herbicide and plant growth regulator. Related studies have shown that 2,4-D has neurotoxicity, ability to disrupt endocrine function, genotoxicity, carcinogenicity, and reproductive toxicity. [Objective] This experiment is conducted to investigate the effect of 2,4-D exposure on reproductive system of female rats, and to preliminarily explore the potential ameliorative effect of Lycium barbarum polysaccharide (LBP) and its possible mechanism. [Methods] Twenty-four SPF female SD rats with six rats in each group were randomly divided into a blank control group (deionized water 1 mL·d−1), an exposure group (75 mg·kg−1 2,4-D), an LBP control group (50 mg·kg−1 LBP), and an LBP intervention group (75 mg·kg−1 2,4-D + 50 mg·kg−1 LBP). The rats were given intragastric administration once a day for 28 consecutive days. Body weight was measured every two days. After exposure, ovary and uterus were weighed and organ coefficients were calculated; the pathological changes of ovary and uterus were detected by hematoxylin-eosin staining (HE); the level of estradiol (E2) in serum was detected by ELISA; the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) in serum were measured by corresponding kits; the apoptosis of ovarian and uterine cells was detected by TUNEL fluorescence staining; and the protein expression levels of Fas, FasL, FADD, Pro-Caspase-8, Cleaved-Caspase-8, Pro-Caspase-3, and Cleaved-Caspase-3 in ovarian tissues were detected by Western blotting. [Results] Compared with the blank control group, the ovarian structure of the exposure group was abnormal, the number of follicles at different developmental stages decreased, morphological changes were observed, and the number of atretic follicles increased; the endometrium was incomplete, with different degrees of nuclear pseudostratification and decreased number of glands in lamina propria. Compared with the exposure group, the ovarian structure of the LBP intervention group was complete, and the follicles at different developmental stages increased in amount, remained intact, and were arranged closely; the uterine structure was relatively intact, showing decreased endometrial loss and nuclear pseudostratification. There were significant differences in the levels of SOD, GSH-Px, E2, and MDA among the four groups (F=86.1, 26.2, 43.3, and 22.3, all P