The Effect And Mechanisms Of Propofol On Learning And Memory Function Of Space In Hyperlipidemia Rats

Objective:1)To research subanesthesia, sedation and anesthesia threedifferent doses of propofol on learning and memory function in rats withhyperlipidemia;2) To study the3doses of propofol in hyperlipidemic ratsneurons in the phosphorylation of Tau protein expression levels;3) To study theeffects of3doses of propofol on hippocampal neurons β-amyloid aggregatesformed in hyperlipidemic rats senile plaques.Method:1) Fourty-five adult maleSD rats, weighing200±20g,were randomly divided into basic diet group (10rats) and the high fat diet group (35rats). After6weeks,7rats were randomlyselected.Then take the tail vein blood to determin the lipids;2) According torandom number table, the successful model of28hyperlipidemic rats wererandomly mean divided into4groups. P10group, P30group, P75group weregiven intraperitoneal injection of1%propofol (10,30,75mg/kg d), the controlgroup(G group) received intraperitoneal injection of normal saline (75mg/kg d).The four groups were injected five days in a row;3) Using the Morris watermaze to detect of spatial learning function.The first1-6days, after administrationof propofol,finding the experimental rats’ incubation period by positioningnavigation and additional experiments;The7th day, using spatial search experiment to test times of acrossing platform and detect rat spatial memoryfunction;4)After eight days propofol administered,given heart perfusion,removed brains,isolated hippocampus.After sliced, made Congo red stainingfinding the situation about senile plaques deposition in rat hippocampalneurons;made immunohistochemistry staining detecting the expression aboutphosphorylation of Tau protein in hippocampal neurons. Software ipwin32analysis Tau protein phosphorylation positive cells mean optical density value.Results:1) Place navigation test: the escaped latency of P30group,P75group isobviously longer than group P10and group G(P<0.05),and the difference ofescape latency between group10and group G has no statistically significance(P>0.05);2) Navigation test’s additional experiments: the escaped latency ofgroup P30,group P75is obviously longer than group P10and group G(P<0.05),and the difference of escape latency between group10and group Ghave no statistically significance (P>0.05);3) Spatial probe experiments: groupP30, group P75representing the number of times acrossing platform obviouslyfewer than group P10and group G (P<0.05),the difference about crossingplatform between group P10with group G has no statistically significance(P>0.05);4)Immunohistochemical staining: the difference of the average opticaldensity between P30group,P75group with P10group,G group has statisticallysignificance (P<0.05), and the difference between group P10with group G hasno statistically significance(P>0.05);5) Congo red staining: group P30,groupP75can see the senile plaques, and group P10, group G showed no senile plaquedeposits.Conclusions:1) single or multiple given subanesthetic doses propofolwere not found to affect learning memory function in hyperlipidemia rats;2)single or multiple given sedative or anesthetic doses propofol can damagespatial learning and memory in rats with hyperlipidemia ability, and afterdiscontinuation of propofol still has a long way damage on learning and memory in hyperlipidemia rats, which may be concerned with β-amyloid aggregationincreased and then senile plaques formed and phosphorylated Tau protein levelswere significantly increased. As for sedation or anesthetic dose propofol, afterstopping administered spatial learning and memory when will be able to resumenormal or whether it can return to normal, and whether phosphorylated Tauprotein with senile plaques formed by β-amyloid aggregates cooperative orindividual work leads to learning and memory impairment in rats remains to befurther studied.