Basic Exploratory Study of Bisphenol A (BPA) Dietary Administration to Istrian Pramenka Rams and Male Toxicity Investigation

Abstract

Bisphenol A (BPA), an endocrine-disrupting chemical and environmental pollutant, has been reported by many researchers to induce male reproductive toxicity in different experimental models. In this study, we investigated whether long-term exposure for two months to 25 µg/kg body weight (low dose) of BPA affects spermatogenesis or sperm quality in young Istrian Pramenka rams exposed via diet. We evaluated body and testicular weights, histopathology of testes and epididymides, and sperm analyses, and compared these parameters between the group of treated rams and the control group of rams. Although there were some differences between the two groups, these differences were not large or statistically significant. The only statistically significant difference was the lower epithelial height of seminiferous tubules in treated rams, compared to control rams. In addition to assessing toxicity, BPA concentrations in the blood plasma of treated rams were determined after the first administration, and the toxicokinetic parameters of total BPA were calculated. In this study, no major signs of altered reproduction in rams were detected.

Experimental Exposure to Bisphenol A Has Minimal Effects on Bone Tissue in Growing Rams—A Preliminary Study

“…Serum and bone parameters of bone metabolism, mass, geometry (length, width, cross-sectional architecture), mineral content, and biomechanics seemed to be only slightly affected in the BPA group, suggesting no major biological effects in long bone tissues. Similar results were previously observed for ram body mass and reproductive parameters [ 51 ]. Rams’ internal exposure to BPA was detected in the BPA-exposed group, as previously reported in the Materials and Methods [ 48 , 51 ].…”

“…The rams were premedicated with xylazine i/v (2 mL Xylased 5%, Chanelle Pharmaceuticals Ltd., Loughrea, Ireland) and euthanized after 7–10 min with pentobarbital (Exagon, Richter Pharma, Wels, Austria; 2 mL/10 kg bw). After euthanasia, we dissected the left and right femur bones for further analysis and collected the liver and kidneys for the study of edible tissues [ 48 , 51 ]. The same veterinarian checked the health status of the animals throughout the procedure, weighed the animals weekly, obtained blood samples, and performed anesthesia and euthanasia at the end of the procedure.…”

“…Throughout the procedure, extreme care was taken to ensure that the animals were not exposed to uncontrolled BPA exposure from products, i.e., glass or BPA-free materials were used [ 52 ]. The absence of BPA contamination in water, pellets, and hay was verified [ 51 ].…”

“…Previously published studies on these rams demonstrated the average maximum plasma concentration of total BPA in the blood plasma of rams from the BPA group was 10.93 µg/L, measured after the first administration [ 51 ]. In the same group, significant BPA concentrations were found in the liver and kidney, where BPA was metabolized and eliminated, with mean ± SD concentrations of the aglycone form of 1.01 ± 0.71 µg/kg and 0.59 ± 0.45 µg/kg, respectively, and of total BPA of 4.70 ± 1.34 µg/kg and 16.62 ± 4.78 µg/kg, respectively [ 50 ].…”

“…Blood was collected from the jugular vein in the morning (9–10 AM), before pellet feeding [ 46 ], and three times during the procedure (a day before the first BPA exposure, on Day 31, and at the end of the procedure on Day 64 of BPA exposure). It was collected in glass heparinized vacuum tubes [ 51 ] containing no anticoagulant, centrifuged within 30 min of collection (3000× g for 10 min), and stored at −20 °C during transport and at −80 °C until analysis. Serum biochemistry to assess renal and hepatic function, i.e., levels of urea, creatinine, cholesterol, triglycerides, aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT) activity, as well as levels of calcium (Ca) and inorganic phosphate (PO 4 ), were analyzed in addition to bone turnover markers, including C-terminal telopeptide of type I collagen (CTX-I) and P1NP.…”