The changes in reproductive system of female rats with experimentally induced diabetes and the effects of lycopene on these changes

In this study, I have attempted to identify the changes that occurred in the genital system organs of female rats with experimental diabetes and the effects of orally administered lycopene upon these changes. In the study, 30 adult female Wistar Albino rats (average body weight 160 g / 4 months old) were used. The experimental diabetes was induced using a single dose of 50 mg/kg streptozotocin (STZ) within 0.01 M citrate buffer administered intraperitoneally. Rats with a blood glucose level on an empty stomach of 250 mg/dl or more after 3 days were included in the study. 3 weeks after diabetes was induced using streptozotocin, the control and diabetic rats were randomly seperated into 4 groups as follows; control + corn oil (n=6), control + lycopene (n=6), diabetes + corn oil (n=8) and diabetes + lycopene (n=10). The control+lycopene and diabete+lycopene groups of rats were fed with 4 mg/kg lycopene dissolved in 4 ml/kg corn oil using a gavage for 4 weeks. The control+corn oil and diabetes+corn oil rats were fed with 4 ml/kg corn oil every day. During the last week of the lycopene application, all animals in all groups were tested to see whether they displayed regular oestrus cycles using the vaginal smear method. At the beginning and end of the study (week 8) the body weights of all the subjects were measured. The blood glucose levels were measured at the beginning of the study, at the beginning of the lycopene application (week 4) and at the end of the study (week 8). At the end of the study, the animals in the dioestrus period were sacrificed by cervical dislocation under light anaesthetics. Samples were taken from the right ovary, uterus and vagina and fixed in 4% paraformaldehyde. After routine histological monitoring series, the tissues were embedded in paraplast and cross sections 5 μm thick were taken. The left ovary was frozen in liquid nitrogen at -80 °C. All histological and histometric evaluations of tissue cross sections taken were performed using Crossman's triple staining method. Furthermore, the immunochemical connexin-43 expression was identified and the apoptotic cell density was measured using the TUNEL (Terminal Deoxynucleotidyl Transferase dUTP Nick End Labeling) method, while the malondialdehyde (MDA) levels were measured using the ELISA technique in ovary. Also, the Periodic Acid Schiff (PAS) method was used in the histochemical examination of the ovary, uterus and vagina and the Alcian Blue (AB) pH: 2.5 method was used to examine the uterus. In the study, we observed that lycopene had no effect on blood glucose levels in diabetic rats on an empty stomach. However, we identified that diabetic rats had an uneven oestrus cycle. With the effect of the diabetes in the ovary the vacuolisation of the corpus luteum, hyrdopic degeneration in the in interstitial regions and the numbers of corpus luteum increased, while the diameters of the corpus luteum decreased. Furthermore, for the diabetes+corn oil group, a decrease in the connexin-43 expression was observed in the ovary primordial and atretic follicles, interstitial cells and luteal cells of the corpus luteum. On the other hand, with the effect of diabetes an increase was observed in the ovary MDA level and the number of apoptotic cells in the granulose layers of the large antral follicles. With the effect of diabetes in the uterus, it was observed that the number of glands, endometrium thickness and PAS positive activity in the gland epithelia decreased, while the AB positive activity in the gland epithelia increased. In the vagina, we observed that diabetes leads to a decrease in the height of the lamina epithelialis and tunica mucularis thicknesses. It has been identified that lycopene administration in diabetic animals increases the expression of connexin-43 in the primordial, secondary and large antral follicles of the ovary. Furthermore, the MDA level and number of apoptotic cells in the ovary were lower, but found to be not statistically significant. The administration of lycopene in diabetic animals did not lead to any histometric or histochemical changes in the uterus, while the thickness of the tunica muscularis in the vagina increased in the diabetes+lycopene group. In conclusion, the changes caused by diabetes in the organs of the female genital system and the existence of protective qualities of lycopene in the some parameters was revealed for the first time. We believe that further studies increasing the lycopene dosage and implementation duration for diabetic animals will show that lycopene has a pronounced antioxidant effect on the female genital system.