Oxidative stress in relation to serotonin under general anaesthesia in dogs undergoing ovariectomy.

Abdominal surgery such as ovariectomy is a traumatic event that can cause oxidative stress. The aim of the present study was to evaluate the concentration of serotonin in relation to ovariectomy-induced oxidative stress in dogs undergoing general anesthesia. Thirty-two female dogs, under general anesthesia, received meloxicam before surgery (0.2 mgkg^-1 SC) and after surgery (0.1 mgkg^-1 OS every 24 h). The physiological, hematological, and biochemical parameters: glycemia, aspartate transaminase (AST), alanine aminotransferase (ALT), total protein, albumin and BUN were evaluated. Oxidative stress was determined by malondialdehyde (MDA) assay, catalase (CAT), superoxide dismutase (SOD), myeloperoxidase (MPO) and butyrylcholinesterase (BuChe) at baseline, 36 and 48 h after the last administration of meloxicam. Serotonin (5-HT) concentration was also evaluated at baseline, 36 and 48 h after the last administration of meloxicam. Responses to surgical stimulus were evaluated. Physiological and hematological parameters they fell within the normal ranges for anesthetized dogs. Glycemia increased, albumin levels decreased after surgery. No rescue analgesia was required. MDA and 5-HT concentrations significantly increased from the baseline at 36 and 48 h after surgery (p < .001). 5-HT levels could be used as an indicator for oxidative stress induced by surgery and it might be employed for objectively quantifying the well-being of the surgical patient.