Resveratrol ameliorates bisphenol A-induced testicular toxicity in adult male rats: a stereological and functional study

Abstract

Background: Bisphenol A (BPA) is one of the most widely used synthetic chemicals worldwide. BPA as an endocrine disruptor affects the reproductive systems through estrogenic and antiandrogenic proprieties. Resveratrol (RES) as a natural polyphenol and potent antioxidant exhibits protective effects against reproductive toxicity by inhibiting of oxidative stress. 48 male rats were divided into eight groups (n=6), including CONTROL, OLIVE OIL (0.5 ml/ day), Carboxy methylcellulose (CMC) (1 ml of 10 g/l), RES (100mg/kg/day), low dose of BPA (25 mg/kg/day), high dose of BPA (50 mg/kg/day), low dose of BPA + RES, and high dose of BPA + RES. All treatments were done orally per day for 56 days. At the end of the 8th week, blood samples were collected for hormone assays. Then, the sperm parameters were analyzed, and the left testis was removed for stereological study.

Results: We showed a significant decrease in sperm parameters in the low and high doses of BPA groups compared to control groups (P<0.05). The volume of testicular components as well as the diameter and length of seminiferous tubules significantly reduced (11-64 %), and the total number of the testicular cell types decreased (34-67 %) on average in the low and high doses of BPA groups. Moreover, serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone hormones concentration showed a significant reduction in both doses of BPA groups (P<0.01). Nonetheless, treatment with RES could ameliorate all the above-mentioned changes in the low and high doses of BPA groups (P<0.05).

Conclusions: RES could prevent BPA-induced testicular structural changes and sperm quality via improving gonadotropin hormones and testosterone levels.

Keywords: Bisphenol A; Resveratrol; Sperm parameters; Stereology; Testicular toxicity.

Fig. 1

Flow chart of the experimental design

Fig. 2

Testicular histological evaluation. Representative photomicrographs of testis sections stained with hematoxylin & eosin (H&E) in the CONTROL (A), low dose of Bisphenol A (BPA-LOW) (B), high dose of BPA (BPA-HIGH) (C), BPA-LOW + resveratrol (RES) (D), and BPA-HIGH + RES (E) groups. All plates are to the same scale (Scale bar = 200 μm). The images indicate the normal seminiferous tubules (asterisk), and atrophied seminiferous tubules (arrow)

Fig. 3

The evaluation of volume. The box plots represents the volume of the testis (A), germinal epithelium (B), interstitial tissue (C), and seminiferous tubules (D) in the CONTROL, OLIVE OIL, carboxy methylcellulose (CMC), resveratrol (RES), low dose of Bisphenol A (BPA-LOW), high dose of BPA (BPA-HIGH), BPA-LOW + RES, and BPA-HIGH + RES groups. n = 6 in each group. The results were analyzed by one-way analysis of variance (ANOVA) and Tukey’s post hoc test. Data are presented as mean ± SEM. *p < 0.05, **p < 0.01, and ***p < 0.001 vs. CONTROL; #p < 0.05, ##p < 0.01, and ###p < 0.001 vs. BPA-LOW; $p < 0.05 and $$$p < 0.001 vs. BPA-HIGH

Fig. 4

The evaluation of diameter and length of seminiferous tubules. The box plots shows the diameter (A), and the length (B) of seminiferous tubules in the CONTROL, OLIVE OIL, carboxy methylcellulose (CMC), resveratrol (RES), low dose of Bisphenol A (BPA-LOW), high dose of BPA (BPA-HIGH), BPA-LOW + RES, and BPA-HIGH + RES groups. n = 6 in each group. The results were analyzed by one-way analysis of variance (ANOVA) and Tukey’s post hoc test. Data are presented as mean ± SEM. **p < 0.01, and ***p < 0.001 vs. CONTROL; #p < 0.05, ##p < 0.01vs. BPA-LOW; $$p < 0.01 vs. BPA-HIGH

Fig. 5

Evaluation of the germinal cells number. The box plots represents the number of spermatogonia A (A), spermatogonia B (B), spermatocytes (C), and round spermatids (D) in the CONTROL, OLIVE OIL, carboxy methylcellulose (CMC), resveratrol (RES), low dose of Bisphenol A (BPA-LOW), high dose of BPA (BPA-HIGH), BPA-LOW + RES, and BPA-HIGH + RES groups. The results were analyzed by one-way analysis of variance (ANOVA) and Tukey’s post hoc test. Data are presented as mean ± SEM. ***p < 0.001 vs. CONTROL; #p < 0.05, ##p < 0.01, and ###p < 0.001 vs. BPA-LOW; $$p < 0.01 and $$$p < 0.001 vs. BPA-HIGH

Fig. 6

Evaluation of long spermatids, Leydig and Sertoli cells number. The box plots represents the number of long spermatids (A), Leydig (B), and Sertoli (C) in the CONTROL, OLIVE OIL, carboxy methylcellulose (CMC), resveratrol (RES), low dose of Bisphenol A (BPA-LOW), high dose of BPA (BPA-HIGH), BPA-LOW + RES, and BPA-HIGH + RES groups. The results were analyzed by one-way analysis of variance (ANOVA) and Tukey’s post hoc test. Data are presented as mean ± SEM. ***p < 0.001 vs. CONTROL; #p < 0.05, ##p < 0.01, and ###p < 0.001 vs. BPA-LOW; $$p < 0.01 and $$$p < 0.001 vs. BPA-HIGH

Fig. 7

Serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone hormones. The column graphs represent the concentrations of LH (A), FSH (B), and testosterone (C) in the CONTROL, OLIVE OIL, carboxy methylcellulose (CMC), resveratrol (RES), low dose of Bisphenol A (BPA-LOW), high dose of BPA (BPA-HIGH), BPA-LOW + RES, and BPA-HIGH + RES groups. n = 6 in each group. The results were analyzed by one-way analysis of variance (ANOVA) and Tukey’s post hoc test. Data are presented as mean ± SEM. **p < 0.01, and ***p < 0.001 vs. CONTROL; #p < 0.05, ##p < 0.01vs. BPA-LOW; $$p < 0.01 vs. BPA-HIGH