Effects of propfol total intravenous anesthesia on water-maze performances in aged rats

Objective To investigate the effect of propofol on spatial cognitive dysfunction in aged rats.Methods Fifty-six 18 months old male SD rats weighing (549.2±16.4) g were randomly equally divided into 7 groups according to propofol infusion dose [small dose group (S) 30 mg·kg~(-1) ·h~(-1),large dose group (L) 50 mg·kg~(-1)·h~(-1)),infusion time and raised date after propofol infusion [small dose propofol 2 h/d-1d group (S12 group),small dose propofol 4 h/d-1d group (S14 group), large close propofol 2 h/d-1d group (L12 group),small dose propofol 2 h/d-7d group (S72 group), small dose propofol 4 h/d-7d group (S74 group),large close propofol 2 h/d-7d group (L72 group) and control group (C group).Excluded control group,rats in the other six groups were anesthetized with propofol intravenously through the tail vein.The induction dose of propofol for six groups was 10 mg/kg and anesthesia maintenance dose was 30 mg·kg~(-1)·h~(-1) for small dose group and 50 mg· kg~(-1)·h~(-1) for large close group.The infusion time of propofol was 2 h or 4 h according to group division.The rats were kept sleeping during propofol infusion.When the propofol infusion was stopped and rats were expected to wake and keep alive for 1 d or 7 d.All of the rats underwent Morris water-maze (MWM) test four times a day for 5 consecutive days from the 1~(st) or 7~(th) day after propofol intravenous anesthesia.The latency period,swimming speed and normal strategy of MWM test were recorded.Results In 1 d groups,on the 3~(rd) and 5~(th) day of MWM test,the latency period of S12 group and L12 group was significantly longer than that of the control group (P0.05),and the normal strategy of S12 group and L12 group was significantly lower than that of the control group (P 0.05).Conclusion Propofol continuous intravenous infusion may cause transient spatial cognitive dysfunction in aged rats,but does not have long term effect.