Effect of nimodipine combined with 7.5% hypertonic saline on postoperative cognitive function in aged rats

Abstract

Objective To evaluate the effect of nimodipine combined with 7.5% hypertonic saline(HS)on postoperative cognitive function in aged rats. Methods Ninety-six healthy male Wistar rats, aged 18 months, weighing 450-500 g, were assigned into 4 groups(n=24 each)using a random number table: splenectomy group(group S), nimodipine group(group N), group HS and nimodipine plus HS group(group N+ HS). Nimodipine 1 mg/kg was intraperitoneally injected in group N. In group HS, 7.5% HS 4 ml/kg was injected via the caudal vein.The equal volume of normal saline was injected intraperitoneally or via the caudal vein in group S. Splenectomy was performed under sevoflurane anesthesia at 30 min after the end of administration.On 1 day before operation and 3 and 7 days after operation, Morris water maze test was performed, and blood samples from the caudal vein were simultaneously collected for determination of the concentrations of serum S100β protein and neuron-specific enolase(NSE)by enzyme-linked immunosorbent assay. Results Compared with group S, the frequency of crossing the original platform was significantly increased, the escape latency was shortened, and the concentrations of serum S100β protein and NSE were decreased at each time point after operation in N, HS and N+ HS groups(P<0.05). Compared with group N or group HS, the frequency of crossing the original platform was significantly increased, the escape latency was shortened, and the concentrations of serum S100β protein and NSE were decreased at each time point after operation in group N+ HS(P<0.05). Conclusion Nimodipine combined with 7.5% HS exerts better efficacy than either alone in improving postoperative cognitive function in aged rats. Key words: Nimodipine; Hypertonic saline; Aged; Cognition disorders