The protective role of melatonin and agomelatine against oxidative stress following laparoscopic ovariectomy in dogs

Abstract Background The present study was carried out to compare biomarkers of oxidative stress and antioxidant activity of agomelatine and melatonin in bitches undergoing laparoscopic ovariectomy. Twenty-four healthy female dogs were randomly divided into four groups: Control (C), laparoscopic ovariectomy (LO), agomelatine + laparoscopic ovariectomy (ALO), and melatonin + laparoscopic ovariectomy (MLO) consisting of 6 animals each. Melatonin and agomelatine were administered to the MLO group (0.3 mg/kg/day, p.o) and the ALO group (0.3 mg/kg/day, p.o) consequently one day before LO to 7 days post-intervention. Blood sampling was performed on days − 1, 0 (immediately after surgery), 3, and 8 of the study. Total oxidant status (TOS), total antioxidant capacity (TAC), and malondialdehyde (MDA) in sera and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in hemolyzed red blood cells (RBCs) were measured. Results Among all indices analyzed over time, only the MDA index in the ALO group showed a significant difference, being significantly lower on day 3 post-surgery compared to days − 1 and 0 (p = 0.023). Significant differences were observed between groups in terms of TOS, TAC, GPx, and SOD levels. The LO group exhibited a significant increase in the TOS index on day 3 compared to all other groups (p = 0.008). The TAC index experienced the most significant increase in the MLO group on day 0 compared to other groups (p = 0.005), and this trend continued significantly until day 3, only in comparison to the LO and C groups (p = 0.024). Agomelatine significantly increased SOD levels in the ALO group on postoperative day 3 compared to groups C and LO (p = 0.009). GPx levels were significantly elevated in ALO and MLO groups on day 8 compared to groups C and LO (p = 0.003). Conclusion The results of this study demonstrate that melatonin, by increasing total antioxidant capacity, and agomelatine, through enzymatic antioxidant pathways, contributed to the reduction of free radical levels in dogs. The present study revealed that administering agomelatine (0.3 mg/kg/day, p.o) could decrease MDA levels significantly after laparoscopic ovariectomy up to day 3.