Protective effects of oxytocin on maternal aggression in stress model rats

Abstract

Objective To explore the effect of the different doses of oxytocin(OXT) on stress model aggressive behaviour in Wistar rats. Methods According to random number table, 40 pregnant rats were divided into experimental stress groups (A, B, C) and control group(D) with 10 samples in each group.Before forced swimming test, rats in experimental groups(A, B, C)were given OXT via intraperitoneal injection with 0.3 mg/kg, 1.0 mg/kg, 2.0 mg/kg; rats in group D were given equal volume of normal saline in the same way. At the 3rd day all rats were tested with maternal aggression, including mothers' following indices as total aggression times, biting times, pinning times, attack latency and duration of attack.Elevated plus maze(EPM) test was applied to analyze the behavioral changes. Results In terms of the duration of attack and attack latency, the indexes of group A and group D were significantly different from relevant data ((147.60±23.92 )s and(79.70±9.88)s, P 0.05). The duration of attack and attack latency had a significant difference ((3.10±0.87)times, (13.60±5.14)times, (91.30±9.74)s and(167.20±30.02)s, P 0.05). Group C and group D in given indexes had significant differences showing (6.40±1.34)times, (15.10±4.35)times, (23.70±3.46)times, (49.80±5.53)s and(215.60±39.55)s(P 0.05). In EPM, the open arm entry ratio and the open arm time ratio of both group A and group D were significantly different from respective percentage (0.47±0.13) and (0.13±0.05)(P 0.05). Conclusion Oxytocin potentially mediates maternal aggression by attenuating stress, and improves the intimate bonding between mother and pups, which means dose dependency of OXT in this process. Key words: Stress model; Anxiety; Oxytocin; Maternal aggression; Elevated plus maze(EPM)