Protective effect of quercetin on alteration of antioxidant genes expression and histological changes in the dental pulp of the streptozotocin-diabetic rats

•mRNAs levels of SOD1, (CAT), and GPX1 are up-regulated in the dental pulp tissue of diabetic rats.•QC is able to normalize the expression levels of SOD1, CAT, and GPX1 to near-normal status.•Pulp tissue destruction and TAC level alteration in diabetic rats are a consequence of hyperglycemia.•QC can normalize TAC levels in the diabetic group. We aimed to assess the effect of quercetin as one of the most common polyphenols with anti-inflammatory and antioxidant properties on expression levels of catalase (CAT), superoxide dismutase 1 (SOD1), and glutathione peroxidase 1 (GPX1), involved in the detoxification of reactive oxygen species (ROS), and histology of dental pulp in streptozotocin-diabetic rats. Type 1 diabetes mellitus (T1DM) was induced by intraperitoneal injection of streptozotocin in adult male Wistar rats. Animals (n = 24) were equally distributed into control, diabetes, and diabetes treated with quercetin groups. Rats were gavaged daily with quercetin (25 mg/kg) for forty days. To measure the mRNA levels of antioxidant genes, quantitate real-time PCR was applied. The oxidative stress parameters such as total antioxidant capacity (TAC) and histopathological assessments were performed. A significant increase in the relative quantification mRNA levels of SOD1, CAT, GPX1 was detected in diabetic rat dental pulp. Besides, persistent hyperglycemia led to the enhancement of TAC level and degeneration of connective tissue of the dental pulp. Interestingly, quercetin normalized the expression mRNA levels of CAT, SOD1, GPX1 to near the normal level. Moreover, quercetin treatment normalized TAC levels. Because of the crucial role of antioxidants in diabetic complications, the findings of the current study presented a molecular basis for the protective effect of quercetin on dental pulp in diabetic conditions.