Investigating the protective effects of phloretin against the polycycstic ovarian syndrome induced by bisphenol A in rats

Endocrine disruptors are exogen substance or mixtures that cause an adverse effect in organism or organism's generation by impacting the function of endocrine system. In this study, it was examined whether phloretin, which is a phytoestrogen, has a protective effect against the polycystic over syndrome (PCOS) caused by the Bisphenol A (BPA) which is an industrial compound disrupting endocrine system. Phytoestrogens, however, are the naturally occurring plant compounds which have the similar structures to those of oestrogen. In our study, the thirty-six Wistar albino female rats were utilised. The rats were divided into six groups and each group consisted of six rats. The daily doses of ingredients given to each group are as follows. 1. group: Maize oil; 2. group: 50 mg/kg BPA; 3. group: 50 mg/kg testosterone propionate; 4. group: 50 mg/kg BPA+0.5 mg/kg phloretin; 5. group: 50 mg/kg BPA+5 mg/kg phloretin; 6. group: 50 mg/kg BPA+50 mg/kg phloretin. These six groups have been given the subcutenous injection of phloretin first, thereafter BPA for fifteen days. Also, the estrous cycles have been monitored by taking the smear samples. Twenty-four hour after the last dose given, the tissue samples were taken from the ovary, uterus, liver and kidney. The thin sections, which were taken after the tissue follow-up, were analysed under the light microscope. Apart from that, CYP17A1 and CYP11A1 expressions were investigated by performing an immunohistochemical staining on the ovarian tissue. The biochemical analyses of ALT, AST, triglyceride, albumin, creatinine, ure and glucose were made on the serum samples acquired from the blood drawn from the rats' hearts. On the other hand, the levels of FSH, LH, DHT, ERRα and cortisol hormones were checked. The histopathological evaluation indicated that the intense cystic appearences have been observed on the ovarian tissues in the BPA group. Similarly, prolonged diestrus phases have been detected in the smear cycle. It has been reported that the cystic appearences of ovaries in the fifth and sixth phloretin groups have diminished, as it was expected. The CYP11A1 and CYP17A enzymes have been stained intensively on the BPA positive control group tissues depending on the increase in testosterone whereas they were stained weakly in the fifth and sixth groups. Degeneration, congestion and mononuclear cell infiltration have been identified on the kidney and liver tissues. While the serum ure levels showed an increase in the second, third, fourth and fifth groups comparing to the control group, the serum albumin levels increased in the fifth group in contrast to the control group. The serum ALT and AST levels, however, were statistically significant in all groups in comparison with the control group. The serum FSH levels have decreased in all groups comparing to the control group. There was a rise in the serum oestrogen levels of the fifth and sixth groups. The serum DHT levels, on the other hand, showed an increase in all groups as opposed to the control group. Lastly, the serum cortisol level has differentiated only between the second and control groups. As a conclusion, in this PCOS model induced by BPA, it has been recorded that the cystic follicles which were abundantly found on the ovaries have decreased in the fifth and sixth groups. This decrease has been confirmed with the serum samples obtained by the immunohistochemistry staining. KEYWORDS: Bisfenol A, phytoestrogen, polycystic ovarian syndrome, phloretin, rat, endocrine disruptors