| OBJECTIVE: By establishing the model of traumatic brain injury in rats,to observe the changes of interleukin(interleukin IL-6),tumor necrosis factor(tumor necrosis factor TNF-a)and S100 B protion in serum and the expression of nerve growth factor(NGF),BCL-2 and BAX proteins,to investigate the nerve protective effect of liquorice and glycyrrhizic acid on traumatic brain injury in rats.METHODS: All of 90 male SD rats were randomly divided into 5groups(18/ each group): normal control group,sham operation group,mo del group,liquorice water decoction group,glycyrrhizic acid group.The rat model of traumatic brain injury was established.After the success of the model,brain injury were scored neurological deficit in 6h,and the group of liquorice water decoction and glycyrrhizic acid were treated with 2ml drugs by gavage and the normal control group,sham operation group and model group were treated with equal amount of saline,once a day.Each group was selected from three periods of 24 h,72h and 168 h after gavag-e,and 6 rats in each group were taken.When drawing materials,draw bl-ood 4mL in the heart first,the IL-6,TNF-?,S100 B protein were detected by ELISA,and then,the brain was removed and made into slices after t he internal fixation,observation of pathological changes of brain tissue in rats,At the same time,the expression of NGF,BCL-2 and BAX protein s in the brain tissue of rats was measured by immunohistochemistry.RESULTS:(1)Compared with the normal group,the score of neural function defect in model group was significantly higher than that of the normal group in the three time period(P < 0.05).The score of nerve function defect in three time periods of liquorice water decoction group and glycyrrhizic acid group was significantly lower than that of the model group(P<0.05),however,there was no significant difference in the score of nerve function defect between liquorice water decoction group and glycyrrhizic acid group in three time periods.(2)The pathological sections showed that the cortex cells of rats were evenly arranged.The nuclei were stained blue and oval.The nucleolus and contour were clear.No degeneration and necrosis of nerve cells and infiltration of inflammatory cells were observed in normal control group and sham operation group.In the model group,the cells were arranged in disorder,the nucleus retraction and fragmentation were obvious,and the obvious tissue cell edema and a large number of nerve cell necrosis were visible.In the liquorice water decoction group and glycyrrhizic acid group,there were loose tissue in the cerebral cortex,disordered cells,rare neurons,a small amount of nuclear condensation,inflammatory cell infiltration,partial cell edema and glial proliferation.(3)In addition to sham operation group,serum of IL-6,TNF-and S100 B protein levels in model group,liquorice water decoction group and glycyrrhizicacid group were significantly higher than those in normal group at three time periods(P<0.05).Successful model building,compared with the normal control group,the serum IL-6,TNF-,S100 B protein levels in the model group increased immediately in 24h(P<0.05),72 h reached its peak and 168 h declined,but it was still higher than that in the normal control group.The content of IL-6,TNF-?and S100 B protein in the serum of three time rats were lower than that in the model group,and the difference was significant(P<0.05).However,there was no significant difference in the difference between liquorice water decoction group and glycyrrhizic acid group in the same time period(P>0.05).(4)There was a small amount of NGF expression in the brain tissue of the normal group and the sham operation group,and there was no difference between the two groups(P>0.05).After the success of the model,the expression of NGF in the brain tissue of the model group increased and continued to 168 h,but there was no significant difference between the three time periods(P>0.05).Comparison with model group,there was no difference in NGF expression between liquorice water decoction group and glycyrrhizic acid group in 24 h.The expression level increased significantly in two groups in 72h(P<0.05),and reached a peak at 168 h,but there was no significant difference between the two groups.(5)Except for the sham operation group,the expression of BCL-2 protein in the model group,liquorice water decoction group and glycyrrhizic acid group increased in all time periods,and the difference was significant(P<0.05).In the model group,the expression in 72 h was slightly reduced,but the difference between the three time periods was not obvious(P>0.05).Comparison with model group,liquorice water decoction group increased at 24 h and reached thepeak in 168h(P<0.05).There was no difference between glycyrrhizic acid group and the model group in 24 h but the expression of BCL-2 protein in glycyrrhizic acid group was increased at the beginning of 72 h and continued to 168h(P<0.05).There was no difference in the expression of BCL-2 protein positive cells in the brain tissue of liquorice water decoction group and glycyrrhizic acid group in 24h(P>0.05),but in 72 h and 168 h the BCL-2 protein positive cells increased significantly in liquorice water decoction group(P<0.05).(6)The expression of BAX protein in the model group,liquorice water decoction group and the glycyrrhizic acid group increased significantly in the three time segments(P<0.05).After the success of the model,the rats in the 24 h model group appeared BAX protein expression,reached the peak in 72 h and dropped slightly in 168 h.Liquorice water decoction group and glycyrrhizic acid group also had high values in 72 h,but they were significantly lower than those in the model group(P<0.05),and decreased significantly in the 168 h at the time of drug use(P<0.05).There was no difference between the liquorice water decoction group and glycyrrhizic acid group(P>0.05).CONCLUSION: Liquorice and glycyrrhizic acid play a neuroprotective ro-le in severe traumatic brain injury rats,and its mechanism is related to reducing secondary inflammatory reaction and inhibiting cell apotosis.Compared with glycyrrhizic acid,the protective effect of liquorice is more obvious.Besides,other active components of liquorice could participate in the protection of damaged nerve cells. |
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