Modulatory effects of concomitant quercetin/sitagliptin administration on the ovarian histological and biochemical alterations provoked by doxorubicin in a streptozotocin-induced diabetic rat model.

Limited literature was available on the effects of sitagliptin or quercetin treatments on doxorubicin induced ovarian dysfunction in diabetic animals. The study aim was test the efficacy and suggested mechanisms of quercetin/sitagliptin combined treatment on the doxorubicin-induced ovarian toxicity in rat model with streptozotocin-induced diabetes. Forty eight female Wistar rats were divided into six groups: 1) Control; 2) Streptozotocin induced diabetes; 3) Streptozotocin-induced diabetes + doxorubicin ovarian damage; 4) Streptozotocin-induced diabetes + doxorubicin ovarian damage with; 5) Streptozotocin-induced diabetes + doxorubicin ovarian damage with sitagliptin treatment and 6) Streptozotocin-induced diabetes + doxorubicin ovarian damage with concomitant quercetin/sitagliptin treatment. Biochemical tests for serum estrogen, progesterone, insulin, blood glucose, and ovarian levels of malondialdehyde, nitric oxide, and superoxide dismutase and qRT-PCR for NOBOX, FSHr, and iNOS genes were performed. Histological evaluation was done on ovary sections with hematoxylin and eosin and immunohistochemistry for 8-OHdG and iNOS followed by morphometric analysis. The streptozotocin-induced diabetic group showed varying degrees of follicle atresia and altered biochemical parameters, both were marked in the streptozotocin-induced diabetic + doxorubicin group. The mRNA of NOBOX, FSHr, and iNOS genes were disturbed with increased immunoexpression of iNOS and 8-OHdG. Quercetin and/or sitagliptin administration improved all altered histological and biochemical parameters and was more effective as a combined treatment. The study suggested equal efficacy of both quercetin and sitagliptin in mitigating the doxorubicin-induced ovarian toxicity in the streptozotocin diabetic rat model, and the combined therapy showed anti-inflammatory, anti-antioxidant, and anti-DNA damage mechanisms.