One-time And Triple Concussion Rat Startle Reflex Weak To Stimulate Suppression And Changes In Glutamic Acid Decarboxylase

Part 1:A study on prepulse inhibition of the startle reflex (PPI) compared PCC with MCC in ratsObjective:To observe the change of prepulse inhibition of the startle reflex in different_injury times of cerebral concussion in rats and to explore if multiple cerebral concussion(MCC) can result in increasing injury compared with pure cerebral concussion(PCC).Methods:A metallic pendulum striker device of closed brain injury was deployed to duplicate PCC and MCC.in Stragu-Dawley(S-D) rats. The animals were divided into PCC and MCC groups(n=10).One control group was used(n=10).Each group was assessed by basal startle amplitude,startle amplitudes on prepulse trials on three levels of stand stimulating,PPI.Test was from 3 days pre-injury to 27 days post-concussion.Result:Startle amplitude and startle amplitude on prepulse trials are declined after CC,there are significance statistics(P＜0.05) compared with control.PPI of MCC have not significance statistics(P＞0.05).Startle reflex amplitude of PCC reduced in 24 h(P＜0.05),and recovered in 16days.Startle reflex amplitude of MCC reduced in 24 h(P＜0.05),lasted until 28 days.Conclusion:1.The multiple cerebral concussion(MCC) model in rats was established successfully using a metallic pendulum-striker concussive device.2.The damage of sensory gating was worse in MCC rats compared with PCC.Startle reflex amplitude was reduced followed by the injury times of cerebral concussion..Part 2:A study on the changes of glutamic acid decarboxylase 67(GAD67) after PCC and MCC in ratsObjective:To establish the model of pure cerebral concussion(PCC) and multiple cerebral concussion(MCC) in rats,observe the changes of GABA neurons and its nerve fiber post-PCC and post-MCC by studing the expressing of glutamic acid decarboxylase67,so as to understand the neurobiologic mechanisms of cognitive behavioral dysfunction after PCC and MCC in rats.To explore if MCC can increase the injury compared with PCC.Method:The PCC or MCC model was duplicated by using a metallic pendulum-striker concussive devicye.96 female and male Sprague—Dawley rats were randomly divided into tweleve groups: PCC1d,2d,4d,8d,16d,24d group and MCC1d,2d,4d,8d,16d,24d group(n=6,in each group).One control was used(n=6).Using the immunostaining of streptavidin-peroxidase(S-P) method and image analysis system to detect optical density value of GAD67 in the following areas,that is cg11,cg13,S1ULp1,S1ULp3, S1ULp5,Pir,MS,CPU1,CPU2,Acb,RSGb1,RSGb3, S1BF1,S1BF3,S1BF5,Aco,CA1-3,DG1,DG2,Rt and VMH.And the masculine cell in PFC were analysised.Result:(1)The GAD67 positive were located in most brain area.Most of GAD67 positive cell are aligned in PFC and thalamus reticulate structure.GAD67 never fiber are wide distribution in brain.(2)The VOD of GAD67 at median septum level in PCC:Loss of GAD67 was significantly differently in first day in the nucleus of cg11,cg13,S1ULp1,S1ULp3,CPU2,Acb and the trough in 8th day in the area of S1ULp5,Pir,MS,CPU1.(3)The VOD of GAD67 at median septum level in MCC:Loss of GAD67 was significantly differently in second day in the area of CPU1,CPU2,Acb.And the area of cg11,cg13,S1ULp1,S1ULp3,S1ULp5,Pir,MS was significantly differently in 4th day.(4)The VOD of GAD67 at hippocampus level in PCC:The trough of GAD67 in thearea of CA2,CA3,DG1,DG2 was in first day.cg11,cg13,S1ULp1,S1ULp3,S1ULp5,Aco,CA1,Rt was significantly differently in 8th day.(5)The VOD of GAD67 at hippocampus level in MCC:Loss of GAD67 was significantly differently in 4th day in the area of Aco,CA1-3,DG1,DG2,Rt,VMH.The area of cg11,cg13,S1ULp1,S1ULp3,S1ULp5 was significantly differently in 24th day.(6) The positive cell in cerebral cortex was declined post-injury and increased then.By the day of 24th,the positive cell was normal basically.Compared with PCC,the GAD67 positive cell of MCC was declined more.At median septum level:Loss of GAD67 was significantly differently in 16th day in PCC and in 8th day in MCC.At hippocampus level:Loss of GAD67 was significantly differently in 8th day in PCC and in 4th day in MCC.Conclusion:(1)The GAD67 positive were located in most brain area.Most of GAD67 masculine cell are aligned in PFC and thalamus reticulate structure.GAD67 never fiber are wide distribution in brain.(2)The GAD67 masculine cell are declined post-injury and the PCC injury degree was lighter than MCC.Loss of GAD67 was significantly differently in first day,8^th day in PCC and 4^th,24^th day in MCC.It is cue that GAD67 participate the change of cognitive dysfuncion post-injury,and this result was according with the PPI.