Therapeutic Effect Of Vascular Endothelial Growth Factor Combined With Hypertonic Saline On Traumatic Brain Injury In Rats

Objective:In this experiment,we used vascular endothelial growth factor and hypertonic saline for 3 days in the subacute stage after craniocerebral injury(5 days later)to verify whether it can reduce brain edema while retaining the neuroprotective effect of VEGF.Methods:In this study,8-week-old SPF male Wistar rats were randomly divided into sham operation group(Sham),craniocerebral injury group(TBI),craniocerebral injury +hypertonic saline group(TBI+HS),craniocerebral injury + VEGF group(TBI+VEGF)and craniocerebral injury + VEGF+ hypertonic saline group(TBI+VEGF+HS).The animal model of craniocerebral injury was made by the method of free fall.On the fifth day after craniocerebral injury,TBI+VEGF and TBI+VEGF+HS groups pumped VEGF(10 μ g / ml)into the ventricle from the sustained-release pump,and the other three groups received the same amount of artificial cerebrospinal fluid,and the sustained-release pump was administered at the rate of 0.5 μ l / h for 3 days.Within 3days after implantation of the sustained-release pump,the TBI+HS and TBI+VEGF+HS groups were injected with 7.5% hypertonic saline through the caudal vein(2ml scarp kg Q12),and the other three groups were injected with normal saline(2ml hand kg Q12).The modified neurological deficit score(m NSS)was used to evaluate the neurological function of the animals on the 1st,5th and 3rd day after craniocerebral injury operation,respectively.The sustained release pump was removed 3 days after treatment,and the degree of brain edema was detected by MRI.Then the brain tissue was taken out,and the brain water content was measured by dry-wet weight method.Evans blue leakage method was used to reflect the blood-brain barrier permeability,and TUNEL method was used to show apoptotic cells.The protein expression levels of ERG,ZO-1 and MMP9 were detected by immunohistochemistry.Results:(1)m NSS score: the score of sham operation group was 0 at any time point,and there was no significant difference among the experimental groups on the 1st and 5th day after craniocerebral injury,indicating that the injury caused by modeling was homogeneous and the baseline was balanced before drug intervention.After continuous administration for 3 days from the 5th day after operation,the neurological function of the rats in the VEGF intervention group was better than that in the non-administration group,and the difference was statistically significant.(2)MRI examination: there was no obvious edema in normal rats and sham operation group,but there was high signal on the injured side in TBI group,which showed obvious edema;the degree of edema in TBI+HS group was more relieved than that in TBI group;the degree of edema in TBI+VEGF group was more serious than that in TBI group;and the degree of edema in TBI+VEGF+HS group was more relieved than that in VEGF group.(3)Dry and wet weight method: the brain water content in TBI group was significantly higher than that in sham operation group,and that in TBI+HS group was lower than that in TBI group,and that in TBI+VEGF group was significantly higher than that in TBI group and higher than that in TBI+VEGF+HS group,and there was no significant difference in brain water content between TBI+VEGF+HS group and TBI group.(4)Evans blue leakage method: the content of Evans blue in TBI group was significantly higher than that in sham operation group,and that in TBI+HS group was lower than that in TBI group,and that in TBI+VEGF group was significantly higher than that in TBI group and higher than that in TBI+VEGF+HS group.(5)TUNEL method: apoptosis was rarely seen in the sham operation group,but significantly increased in the TBI group and TBI+HS group,and the number of apoptotic cells in the VEGF group was significantly less than that in the above two groups.(6)Immunohistochemistry: the expression of ERG protein in TBI group and TBI+HS group was higher than that in sham operation group,and the expression of ERG protein in TBI+VEGF group and TBI+VEGF+HS group was significantly higher than that in TBI group.The expression of ZO-1 protein in sham operation group was abundant and orderly,and the expression of ZO-1 protein in TBI group and TBI+HS group was lower than that in sham operation group,and the expression of ZO-1 protein in TBI+VEGF group and TBI+VEGF+HS group was significantly lower than that in TBI group.The expression of MMP9 protein in sham operation group was sparse,and that in TBI group was higher than that in sham operation group,and that in TBI+HS group was higher than that in sham operation group,but lower than that in TBI group.Compared with TBI group,the expression of MMP9 protein in TBI+VEGF group and TBI+VEGF+HS group was significantly increased.Conclusion:(1)Dehydration with hypertonic saline after craniocerebral injury can effectively reduce brain edema.(2)VEGF can improve neurological function in subacute stage after craniocerebral injury,which may be related to its promotion of angiogenesis and reduction of neuronal apoptosis,while VEGF can still aggravate brain edema,and its mechanism may include degradation of blood-brain barrier connectin,destruction of normal structure of blood-brain barrier,increased leakage and vasogenic brain edema.(3)VEGF combined with hypertonic saline dehydration in the subacute stage after craniocerebral injury can reduce the extra brain edema caused by VEGF while retaining the neuroprotective effect of VEGF.The combination of VEGF and hypertonic saline is a promising treatment to alleviate the brain injury after traumatic brain injury.