Effects of 7.5% hypertonic saline pre-injection on postoperative cognitive dysfunction in senile rats
Yuan, T.; He, J.; Xie, M.; Huo, S.; Wang, Q.
Zhonghua Yi Xue Za Zhi 95(3): 217-220
2015
ISSN/ISBN: 0376-2491 PMID: 25877035 Document Number: 683441
To explore the effects of hypertonic saline (7.5% NaCl) pre-injection on postoperative cognitive function in senile rats. A total of 60 healthy male Sprague-Dawley rats, aged 18 months, weighting 450-500 g, were randomly divided into 3 groups of control (C); model (M) and hypertonic saline (HS) (n = 20 each). At 30 min pre-operation, the rats of groups C and HS received an injection of 7.5% hypertonic sodium 4 ml/kg via tail vein. And the same volume of saline was injected in group M. Rats of groups M and HS were anesthetized by inhaling 3% sevoflourane and underwent splenectomy while group C inhaled merely pure oxygen. Escape latency and frequency of crossing original platform were assessed by Morris water maze on 1 day pre-operation and 1, 3, 7 days post-operation. The rats were randomly taken for detecting the intracellular [Ca²⁺]i and apoptotic rate of hippocampal neuron with flow cytometry. And ultrastructures of hippocampal neurons were observed with transmission electron microscope at 1 day pre-operation and 1, 7 days post-operation. Compared with pre-dosing value, escape latency was significantly prolonged, the frequency of crossing original platform decreased and apoptotic rate and [Ca²⁺]i increased at each time point post-operation in groups M and HS. And no significant changes were found in the above-mentioned parameters in group C. Compared with group M, escape latency was significantly shortened, the frequency of crossing original platform increased and apoptotic rate and [Ca²⁺]i decreased at each time point post-operation in group HS. Pathological changes were found in groups M and HS and the damage was more severe in group M than that in group HS. And no significant pathological change was found in group C. Infusing 7.5% hypertonic saline can improve postoperative cognitive function of senile rats. And it may be due to a decreased apoptotic rate of hippocampal neurons.