Evaluation of the effects of curcumin and vitamin D on the apelinergic system

Apelin receptor (APJ), apelin (AP) and elabela (apela, toddler, ELA) constitutes apelinergic system. The known effects of the apelinergic system so far are cardiac inotropic signaling, vasodilation, body fluid homeostasis, metabolism and insulin response, alleviation of oxidative stress and modulation of immune response. Curcumin, a polyphenol derived from Curcuma longa L. (Zingiberaceae), is a potent exogenous nonenzymatic antioxidant with various properties such as scavenging free radicals, reducing reactive oxygen species (ROS) production. Vitamin D is a fat-soluble vitamin that reduces oxidative stress and chronic inflammation and protects mitochondrial respiratory functions. In our study, it was aimed to evaluate the effects of vitamin D and curcumin on apelinergic system and oxidant-antioxidant status. Forty-two Wistar rats divided into six groups were included in the study: first group (control) received distilled water, second group received 200 mg/kg/day curcumin, third group received 0.4 µg/kg/day (16 IU/kg) vitamin D3, fourth group received 200 mg/kg/day curcumin and 0.4 µg/kg (16 IU/kg) vitamin D3, the fifth group received 400 mg/kg/day curcumin, the sixth group received 400 mg/kg/day curcumin and 0.4 µg/kg (16 IU/kg) vitamin D3. Serum apelin, elabela, nitric oxide (NO), asymmetric dimethyl arginine (ADMA), total oxidant status (TOS) and total antioxidant capacity (T-AOC) levels were measured by ELISA method. Statistically significant difference was found in terms of groups in T-AOC parameter. When the control group and other groups were compared, total antioxidant capacity and ADMA levels were significantly higher in the curcumin-treated groups. (p<0,001; p<0,05). No statistically significant difference was found between the groups in other parameters. According to the findings, the correlations between NO-TOS in Group I, AP-ELA in Group III, NO-TOS in Group IV, and AP- T-AOC parameters in Group VI were found to be statistically significant (p<0.05), no significance was found in other correlation analyses. Our results suggest that curcumin and vitamin D may cause a tendency to decrease in total oxidant capacity and increase in total antioxidant capacity due to their antioxidant properties, and that curcumin, alone or in combination with vitamin D, has an important prophylactic role by reducing the risk of oxidative damage.