Effects of post-propofol anesthesia on cognitive function and hippocampus proteome expressions in aged rats

Objective To investigate the effects of post-propofol anesthesia on cognitive function and hippocampus proteome expressions in aged rats. Methods Thirty healthy male Wistar rats aged 20 months were randomly divided into control group(n=15)and propofol group(n=15). The control group was injected with normal saline of 6 ml/kg intraperitoneally and propofol was injected intraperitoneally with propofol 60 mg/kg.The rats in both groups underwent Step-down Test to assess cognitive function at the first day and at the seventh day after the termination of drug administration.Five rats were decapitated randomly each time after the two step-down tests and their hippocampi were removed for two-dimensional gel electrophoresis and mass spectrometric analysis. Results In the step-down test, aged rats in the propofol group showed significantly learning impairment and decreased memory abilities at the 1st day after propofol anesthesia as compared with those in the control group.In learning phase of the 1st day, the latency of the propofol group is(29.5±7.6)s as compared with(19.7±7.0)s of the control group, while the error time is 3.6±1.2 vs.1.6±0.8 in the propofol group vs the control group, and the total time of electric shock is(65.2±10.6)s vs.(42.7±10.3)s in the propofol group vs the control group(all P<0.01). The latency of the memory phase in the propofol group is also decreased as compared with that in the control group(31.4±14.3)s vs.(111.2±23.7)s, (P<0.01). On the 7th day after anesthesia, there was no significant difference between the two groups.There were 17 differentially expressed proteins on the 1st day after propofol anesthesia, 6 of them were up-regulated and 11 proteins were down-regulated(P<0.05). On the 7th day, there were 10 differentially expressed proteins, and the expression of 5 proteins was down-regulated(P<0.01). Conclusions Aging rats receiving propofol anesthesia show cognitive function decline, but do not show a long-term decline.The mechanism may be related to the different expressions of hippocampal proteins. Key words: Propofol; Hippocampus; Cognition disorders; Proteomics