Effects of social isolation on the cognition and expression of 5-HT2C receptor and ADAR1 in BALB/c mice

Objective To explore the effects of social isolation on the cognition and expression of 5-HT2C receptor(5-HT2CR) and adenosine deaminase that act on RNA 1(ADAR1) in BALB/c mice. Methods The healthy BALB/c mice were isolated for 2, 4, and 8 weeks individually since postnatal 21 days respectively to set up isolation mice model, the same age mice without isolation were regarded as control group. The new object location and the new object recognition tests were used to measure the spatial and non-spatial cognitive function, and western blot was used to measure the protein expression of 5-HT2CR and ADAR1. Results The new object location test showed that the spatial discrimination index (DI) of BALB/c mice isolated for 2 weeks was decreased significantly compared with the control group(control group was (0.075±0.340), isolation group was (-0.653±0.308), P<0.05), and no obvious difference was found for the group isolated for 4 and 8 weeks. The new object recognition test showed that the non-spatial DI of BALB/c mice isolated for 2 and 4 weeks were decreased significantly compared with the control group(control 2 weeks group was (0.088±0.210), isolation 2 weeks group was (-0.945±0.194), P<0.05; control 4 weeks group was (0.105±0.267), isolation 4 weeks group was (-0.506±0.215), P<0.05), and no obvious difference was found for the group isolated for 8 weeks.Compared with the control group the expression of 5-HT2CR and ADAR1 in the hippocampus were decreased significantly for the group isolated for 2 weeks. (5-HT2CR: control group was (1.025±0.144), isolation group was (0.891±0.026), P<0.05.ADAR1: control group was (0.839±0.120), isolation group was (0.629±0.094), P<0.05). Conclusions Two week social isolation results in the decrease of spatial and non-spatial cognitive function in BALB/c mice, in the meanwhile, social isolation stress results in the obvious decrease of 5-HT2C receptor and ADAR1 protein expression in the hippocampus of BALB/c mice. Key words: Social isolation; Cognitive function; 5-HT2C receptor; Adenosine deaminase that act on RNA 1