Effect Of Stellate Ganglion Block On Postoperative Cognitive Dysfunction In Aged Rats

Objective:To investigate the effect of stellate ganglion block on postoperative cognitivedysfunction in aged rats and assess the possible mechanism, providing an effectiveclinical and theoretical basis for the prevention of postoperative cognitive dysfunctionMethods:Sixty-four male Sprague-Dawley rats, aged18-20months, weighing500-700g,were randomly divided into4groups （n=16each）: control group （group C）, operationgroup （group O）, normal saline+operation group （group NS） and SGB+operationgroup （group SGB）.Ggroup O cervical ganglion were exposed and splited but notblockï¼›group SGB cervical ganglion were exposed and splited，then blocked with0.25%bupivacaine0.15mlï¼›group N cervical ganglion were exposed and splited，theninject the equal volume of normal saline，Ggroup O,NS and SGB were underwentexploratory laparotomy starting from15min after the end of administration. Bloodcollection to test serum S100βand NSE at the time before induction of general（T₁,baseline），at the end of operation，and at12,24and48h after operation (T_2-5)ï¼›Tworats were chosen from each group at T₃, T₄and72h after operation （T6） andsacrificed and the hippocampi were removed for microscopic examination.ï¼›Cognitivefunction were assessed by Morris water maze test on others rats.Result:（1） Compared with group C, the escape latency wag significantly prolonged on1-5days after operation in groups O and NS, the escape latency wag significantlyprolonged on1and2days after operation in group SGB, and the frequency ofcrossing the original platform was decreased（P<0.05）. Compared with group O, Theescape latency was significantly shorted on2-4days after operation in group NS（P<0.05），and there was no significant difference in frequency of crossing the originalplatform in group NS（P>0.05）. Compared with group NS, The escape latency wassignificantly shorted on1-5days after operation, and the frequency of crossing theoriginal platform was increased in group SGB（P<0.05）. （2） Compared with group C, the serum S100β and NSE concentrations weresignificantly increased at T_2-5in groups O, NS and SGB （P<0.05）. Compared withgroup O, the serum S100βand NSE concentration significantly decreased at T_3-5ingroup NS （P<0.05）, Compared with group NS, the serum S100βand NSEconcentration significantly decreased at T_2-5in group SGB （P<0.05）.（3） The hippocampal neurons morphology was not seen abnormal at each time ingroup C. There are few hippocampal neurons appear cell degeneration at T₃,T6ingroup O,NS and SGB. The number of hippocampal neurons was significantly largerat T4,6in group SGB than in group NS.Conclusion:Surgical operation can cause cognitive dysfunction in aged rats, Stellate ganglionblock can decrease serum S100β protein and NSE concentration, improve brain tissuepostoperative pathological changes, which may be of some protection for cognitivefunction.