Gastrodin Improves Spatial Learning And Memory Impairments In Rats With Acute Neuroinflammation Induced By Lipopolysaccharide

Objective: A single intraperitoneal injection of lipopolysaccharide was used to establish an adult rat model of acute neuroinflammation-induced spatial learning and memory impairment,observe the improvement of gastrodin treatment on the inflammation in rats with acute neuroinflammation induced by lipopolysaccharide,and explore the effect of gastrodin on spatial learning and memory in rats and the effect of Tau,P-Tau(Ser202)and Aβ protein expression in the hippocampus.Method:Part 1 Establishment of a model of rat spatial learning and memory impairment caused by acute neuroinflammationHealthy adult SD rats,N=30,were divided into two groups according to random number method: blank group(n=6),model group,namely lipopolysaccharide group(L group,n=24).The blank group is not treated;the L group is divided into 4 subgroups according to the time of sampling: L12 h group(n=6),L24 h group(n=6),L3 d group(n=6),L7 d group(n=6),That is,the samples were taken at 12 h,24h,3d and 7d after a single intraperitoneal injection of LPS.(1)Behavioral testing:(1)Before modeling,each group of rats used Morris water maze for 1 day and 5 days of adaptive training and positioning navigation experiments,and recorded the daily escape latency data of the rats to evaluate the rats’ performance The baseline level of spatial learning and memory ability is consistent.(2)After modeling,complete the space exploration experiment to detect the spatial memory ability of rats;(2)Detect inflammatory factors:(1)ELISA method: detect serum inflammatory factors IL-1βand TNF-α;(2)ELISA method: detect hippocampal IL-1β,TNF-α.Part 2 Gastrodin improves spatial learning and memory in rats with acute neuroinflammation(1)Adult SD rats,N=66,were divided into three groups according to the random number method: blank group(n=6),LPS group(L group,n=30),LPS+Gastrodin group(L+G group,n=30).①Blank group: free feeding,no treatment.②L group: According to the 3d,7d and 14 d time points after a single intraperitoneal injection of LPS(5mg/kg),they were divided into 3 subgroups: L3 d group(n=6),L7 d group(n=12),L14 d group(N=12).Among them,the L3 d,L7d and L14 d groups were subjected to ELISA(n=6);the L7 d and L14 d groups were immunohistochemical(n=6).③(L+G)group: After a single intraperitoneal injection of LPS(5mg/kg),according to the continuous gastric gavage time of gastrodin(30mg/kg)divided into 3 subgroups,namely:(L+G)3d group(Gastrodin Gavage for 3 days,n=6),(L+G)7d group(Gastrodin for 7d,n=12),(L+G)14d group(Gastrodin for 14 d,n=12).Among them,(L+G)3d,(L+G)7d and(L+G)14d groups were tested by ELISA,(n=6);(L+G)7d and(L+G)14d groups were tested for immunohistochemistry,(N=6).In the first part of the experiment,the acute neuroinflammation-induced spatial learning and memory impairment model in rats was established.At the behavioral level,no spatial learning and memory impairment in the L3 d group was found,so the second part of the L3 d and(L+G)3d group did not Detection of immunohistochemistry-related memory proteins.(2)Behavioral testing: Same as the first part of the experiment.(3)Detection of inflammatory factors: Same as the first part of the experiment.(4)Immunohistochemistry: Tau,P-Tau(Ser202)and Aβ protein expression in hippocampus.Result:Part 1 Establishment of a model of rat spatial learning and memory impairment caused by acute neuroinflammation1.Behavioral results of water maze(1)Adaptive training: rats in each group have normal swimming ability;(2)Positioning and sailing experiment before modeling: the blank control group and model group of rats positioning and sailing experiment from the first day to the fifth day of escape latency.The increase in training days showed a trend of shortening.Compared with the first day and the second day in each group,the difference in the escape latency after the third day was statistically significant(p<0.05);and in the next three days of testing.There was no significant difference in escape latency within and between groups(p>0.05).It shows that all rats have formed stable memory before modeling,and the baselines of learning and memory ability of rats in each group are consistent;(3)Space exploration experiment after modeling: Compared with the blank control group,the rats in the model group have space exploration indicators The number of crossings in the effective area,the percentage of crossings in the original platform quadrant and the percentage of movement distance of the rats in the L7 d group were significantly reduced(p<0.05).2.ELISA method to detect serum IL-1β and TNF-α(1)Compared with the blank group,the expression of serum inflammatory factor IL-1β in each subgroup of the model group,namely the L12 h group,L24 h group,L3 d group and L7 d group,increased,and IL-1β expression in the L12 h group,L24 h group and L7 d group The expression of 1β increased significantly(p<0.05);(2)Compared with the blank control group,the expression of serum inflammatory factor TNF-α in rats of the model group,namely L12 h group,L24 h group,L3 d group and L7 d group,increased,and L12 h The expression of L24 h group and L24 h group increased significantly(p<0.05).3.ELISA method to detect IL-1β and TNF-α in hippocampus(1)Compared with the blank group,the expressions of hippocampal inflammatory factors TNF-α and IL-1β in the model group increased(p<0.05),and the expressions of TNF-α and IL-1β in the L12 h group reached the peak.Part 2 Gastrodin improves spatial learning and memory in rats with acute neuroinflammation1.The effect of gastrodin on the behavior of rats(1)Adaptive training: rats in each group have normal swimming ability;(2)During the positioning and sailing,the escape latency of each group of rats from the first day to the fifth day of the positioning and sailing experiment decreased as the number of training days increased.In each group,compared with the first day and the second day within each group,the difference in escape latency after the third day was statistically significant(p<0.05);and in the next three days,there was no significant difference in escape latency within and between groups(p>0.05).It shows that all rats have formed stable memory,and the baseline of learning and memory ability of rats in each group is consistent;(3)Space exploration experiment:(1)Compared with the blank group,the number of crossings in the effective area of the rats in the L7 d group,the percentage of crossings in the original platform quadrant and the percentage of the movement distance were significantly reduced(p<0.05);the number of crossings in the effective area of the L14 d group,The percentage of movement distance was significantly reduced(p<0.05);(2)Compared with the L3 d group,the number of platform crossings,the number of effective area crossings,the percentage of the number of crossings of the original platform quadrant,the retention time and the percentage of movement distance in the(L+G)3d group increased,but the difference was not statistically significant(p>0.05);(3)Compared with the L7 d group,the number of effective area crossings,the percentage of crossing times of the original platform quadrant,the retention time and the percentage of movement distance increased in the(L+G)7d group;(4)Compared with the L14 d group,the number of platform crossings and effective area crossings in the(L+G)14d group increased.It is suggested that after a single intraperitoneal injection of LPS,the spatial learning and memory of rats are impaired,and the spatial learning and memory ability of rats is improved after gastrodin is administered.2.The effect of gastrodin on IL-1β and TNF-α in peripheral serum of rats(1)Compared with the blank group,the overall expression of serum inflammatory factors TNF-α and IL-1β in the L3 d,L7d and L14 d groups increased,and the difference in serum IL-1β expression between the L7 d and L14 d groups was statistically significant(p<0.05);(2)Compared with the L7 d group,the serum IL-1β expression in the(L+G)7d group decreased,and the difference was statistically significant(p<0.05);(3)Compared with the L14 d group,the serum TNF-α and IL-1β expressions in the(L+G)14d group decreased,and there was a statistically significant difference in the decrease of TNF-α(p<0.05).3.The effect of gastrodin on IL-1β and TNF-α in the hippocampus of rats(1)Compared with the blank group,the expressions of hippocampal inflammatory factors TNF-α and IL-1β in the L3 d,L7d,and L14 d groups all increased,and the difference was statistically significant(p<0.05);(2)Compared with the L7 d group,the expression of TNF-α in the hippocampus of the(L+G)7d group was reduced,and the difference was not statistically significant(p>0.05);(3)Compared with the L14 d group,the hippocampal TNF-α expression in the(L+G)14d group The expressions of-α and IL-1β were reduced,and the difference was statistically significant(p<0.05).4.The effect of gastrodin on the expression of Tau,P-Tau(Ser202)and Aβ protein in the hippocampus of rats(1)Results of Tau protein expression level in the hippocampus:(1)Compared with the con group,the expression of Tau protein in the hippocampal CA1 and DG areas of the L7 d group decreased slightly,and the difference was not statistically significant(p>0.05);the expression of Tau protein in the hippocampal CA1 area of the L14 d group was slightly decreased,and the difference was not statistically significant Significance(p>0.05);Tau protein expression in CA3 and DG regions increased in L14 d group(p<0.05).(2)Compared with the L7 d group,the expression of Tau protein in the hippocampus CA1,CA3,and DG areas of the(L+G)7d group decreased,and the difference was not statistically significant(p>0.05);the CA1,CA3,and DG areas of the L14 d group The expression of Tau protein increased(p<0.05).(3)Compared with the L14 group,the expression of Tau protein in the hippocampus CA1,CA3,and DG areas of the(L+G)14d group decreased overall,and the difference was not statistically significant(p>0.05).(2)Results of P-Tau protein expression level in the hippocampus:(1)Compared with the L7 d group,the expression of P-Tau protein in the CA1,CA3 and DG areas of the(L+G)7d group increased(p<0.05);the expression of P-Tau protein in the CA1,CA3 and DG areas of the L14 d group increased(p<0.05);(2)Compared with the L14 d group,the expression of P-Tau protein in the hippocampal DG and CA3 areas of the(L+G)14d group increased(p<0.05).(3)Results of Aβ protein expression level in hippocampus:(1)Compared with L7 d group,(L+G)7d group DG area,CA1 area Aβ protein expression increased(p<0.05);L14d group CA1,CA3 area Aβ protein expression increased(p<0.05);(2)Compared with L14 d group,the expression of Aβ protein in hippocampus CA1 and CA3 areas of(L+G)14d group increased(p<0.05).Conclusion: A single intraperitoneal injection of lipopolysaccharide can successfully establish a model of spatial learning and memory impairment in adult rats caused by acute neuroinflammation.Gastrodin can alleviate the acute neuroinflammation induced by lipopolysaccharide in adult rats after continuous intragastric administration,and effectively improve the spatial learning and memory decline of the rats.Its improving effect may be related to the reduction of inflammatory factors in the hippocampus of rats.