Effects Of Surgery On Cognitive Function And Dendritic Spines Of Neurons In Rats Of Different Age

Object:l.To explore the impact of surgery on cognitive function in adult and aged rats.2. We sought to explore the age and region feature of spine density changes after surgery.Methods:(1) The first part of the experiment:①Sprague Dawley (SD) aged rats(18months) and adult rats(2months) were randomly divided into four groups (half male and half female):control (adult rats,n=11,aged rats,n=14), and surgery (adult rats,n=ll,aged rats,n=14). Rats were exposed to sevoflurane anesthesia (4.5%sevoflurane for induction followed by2-2.5%for maintenance) for2h with endotracheal intubation and underwent hepatectomy in the surgery group,monitoring of vital signs and gas concentration. Rats in the control group did not be deposed as surgery group.②Spatial learning and memory were evaluated in the MWM, rats were trained for6days with three trials per day. After training, the memory of rats was detected on1day before surgery and1、3and7days after surgery. The percents of searching time and distance in the targeted area are recorded by smart junior system.(2) The second part of the experiment:Golgi staining was performed with FD Rapid Golgi-stain TM Kit according to the manufactures instructions,Neurons (5CA1neurons/rat,6neurons of cingulate cortex/rat,8DG neurons/rat) were analyzed for calculating spine density. All statistical data were analyzed using SPSS17.0.Results:The first part of the experiment:surgical trauma resulted in impairments in the percents of searching time and distance in the targeted area on postoperative day1and3in aged rats compared with control group,and it was not significant in control group.The second part of the experiment:①surgery and rat age significantly affected apical spine density(F (1,40)=138.99, p<0.001) and basal dendritic spine density(F (1,40)=138.99, p<0.001, for central) of CA1neurons.②the apical dendritic spine density and basal dendritic spine density of control CA1of aged rats was not significant from that of young adult rats (p>0.05) ゛pical dendritic spine density and basal dendritic spine density significantly decreased1d and3d after hepatectomy, compared with that of control aged rats, respectively (P<0.001).Conclusions:The first part of the experiment:. Hepatectomy damaged the memory of aged rats rather than young adult rats.The second part of the experiment:①Hepatectomy induced spine loss of hippocampal neurons of aged rats rather than young adult rats.②Loss of neuronal dendritic spine density induced by surgery is region-dependent and age-dependent.