International Journal of Scientific and Research Publications, Volume 6, Issue 11, November 2016 459 ISSN 2250-3153 www.ijsrp.org Response to Oxidative Stress during Surgery under Ketamine/Propofol Anaesthesia in Acepromazine- Xylazine Premedicated Horses R. Gnanasekar and R. Vijayalakshmi Division of Animal Husbandry, Faculty of Agriculture, Annamalai University, Annamalai nagar – 608002, Tamilnadu, India Abstract- The study was conducted in twelve clinical cases of horses undergoing diagnostic and surgical procedures warranting general anaesthesia. The cases were randomly divided into two groups: group I and group II, each consisting of six horses. Pre- anaesthetic medication done with Xylazine hydrochloride @ 0.5mg/kg and Acepromazine maleate @0.03 mg/kg body weight in both the groups. Ketamine @ 2.20 mg/ kg body weight and 0.05mg/kg/min was used as induction and maintenance agent in group I and Propofol @ 2.0 mg/kg body weight and 0.15mg/kg/min was used as induction and maintenance agent in group II. The total serum protein showed no significant reduction after sedation, after induction, during maintenance and after recovery in both the groups. There was no significant difference in the neutrophil, lymphocyte, eosinophil, and monocyte counts in both the groups. The magnitude of blood glucose level was lower in group II compared to that of group I. Group I exhibited an increase in plasma cortisol level, when compared to that of group II. Index Terms- Horse, Oxidative stress, Ketamine/Propofol, Acepromazine, Xylazine I. INTRODUCTION orses are the most challenging species to anaesthetize and are more prone for potential complications during induction, maintenance and recovery. During anesthesia and perioperative period of surgery, it is important to prevent undue excitement and anxiety. It is also important to maintain normal cardiac output, blood pressure and acid-base balance by ensuring adequate ventilation and oxygenation. The factors responsible for triggering stress and release of oxygen free radicals have to be minimized (Wagner, 1991).Oxidative stress occurred when the production of oxygen free radicals (RSO = Reactive oxygen species) and nitric oxide radicals (NOR) exceeded the scavenging capacity of systemic endogenic antioxidants through enzymatic and non enzymatic pathways (Basu et al., 2001). The reactive oxygen species were hydrogen peroxide, superoxide anion, peroxide radicals, alkoxy radical, peroxy radical and nitric oxide radicals were nitric oxide and peroxynitrite (Brasil et al., 2006). The production of the free radicals was favoured directly by reduced perfusion and issue anoxia and indirectly by anaesthetic and ancillary drugs (Basu et al., 2001 and Ozer and Kaman, 2007). Free radicals induce stress, inflammation, delay in wound healing, prolonged recovery from anaesthesia and post anaesthetic complication on the functional ability of heart, lung, spleen, liver, kidney, red blood corpuscles and muscles (Brasil et al., 2006). Free radicals also interferes with the regeneration of tissues by inducing single bond breakage of DNA in morphology of cells. Xylazine, an alpha 2 adrenergic agonist and Acepromazine, a phenothiazine derivative are commonly used in horses as sedatives as well as pre-anaesthetic agents. Ketamine and propofol are the common induction agents and also useful for maintenance in the field of ambulatory equine practice. The aim of the study was to assess the magnitude of physiological stress in terms of plasma cortisol and oxidative stress in terms of enzymatic and non enzymatic antioxidants. This assay will reflect on the quantum of oxygen free radical in a directly proportional manner. II. MATERIALS AND METHODS Study Animals Horses admitted for various ailments warranting surgery in Teaching Hospital, Madras Veterinary College, Chennai were utilized for the study. 12 horses were randomly selected and grouped into two (group I and group II) with each group consisting of six animals. Pre-anesthetic medication Xylazine hydrochloride @ 0.5mg/kg and Acepromazine maleate @ 0.03 mg/kg body weight by jugular vein was given to all the horses as premedicants. Anesthesia Ketamine @ 2.20 mg/ kg body weight and 0.05mg/kg/min was used as induction and maintenance agent for group I and Propofol @ 2.0 mg/kg body weight and 0.15mg/kg/min was used as induction and maintenance agent for group II horses. Collection of samples and Analysis of data All the blood samples were collected around 10 am to avoid diurnal variation (Taylor, 1989). Blood samples were collected before sedation, after sedation, after induction, during maintenance and after recovery in both the groups. Heparinized blood samples were centrifuged (1500rpm, 10 min) and supernatants were immediately stored at -80°C until analysis. Plasma cortisol was measured quantitatively using competitive Enzyme Linked Immuno Sorbent Assay-ElAgen Cortisol Kit. The activity of superoxide dismutase (SOD) was determined H