| Backgrounds and Objectives:Spinal cord injury is still a severe disease in the world that has received a lot of attention.And it has not been overcome yet.The physical disability and sensory disturbance which caused by spinal cord injury often trouble patients,so the treatment of spinal cord injury still needs our attention.After spinal cord injury,the blood-brain barrier is open,and at the same time the astrocytes are activated.At first the proliferation of astrocyte can prevent further spread of inflammation.However,with the excessive proliferation of astrocytes,glial scars are formed at the wound,which hinders nerve conduction.Therefore,inhibiting the proliferation of astrocytes is an idea for treating spinal cord injury.Hippo-YAP signaling pathway is an important pathway regulating cell growth during mammalian development and plays an important role in maintaining the structure and function of the nervous system.YAP is the only proliferative-related factor in the Hippo signaling pathway.Exploring the expression of YAP in the spinal cord may bring new ideas and therapeutic targets for the treatment of spinal cord injury.Resveratrol is a polyphenolic compound with effects of anti-inflammatory and anti-oxidant.In recent years,The resveratrol play an important role in protecting nerve from being damaged,which has received increasing attention.However there are few reports on the effects of resveratrol on activated astrocytes.In this study,we investigated the expression of YAP molecules in various cells of the spinal cord,determined the relationship between the formation of glial scar and the Hippo-YAP signaling pathway.Then,through the drug treatment of spinal cord injury by resveratrol,the effect of resveratrol on Hippo-YAP signaling pathway in the treatment of spinal cord injury was studied,which provided experimental basis and theoretical support for the treatment of spinal cord injury.It has extremely important clinical significance.Methods:1.In vivo experiments: 1)We used Sprague Dawley rats to establish T9 spinal cord injury model,and divided them into sham group,RES group,DMSO group and Naive group.BBB score was used to evaluate the recovery of motor function at each time point;2)We use immunofluorescence to explore the expression of YAP and GFAP of rat tissue sections on different time-point after spinal cord injury.RNA and protein was extracted from the tissue of the fresh damaged spinal cord at each time point,and use qRT-PCR and westernblot to evaluated the expression of YAP and GFAP on the transcription level and translation level.2.In vitro experiments: We use neonatal rats to primary culture astrocytes,and then divided into two groups(control group and administration group).The control group was cultured normally,and the administration group was treated with resveratrol for 48hours;RNA and protein were extracted from the collected cells of two groups,and the expression of YAP and GFAP were measured in vitro.Results:1.YAP co-express with ?-tubulin III-positive cells in uninjured spinal cord sections,and indicate YAP is mainly expressed in neurons in normal spinal cord.2.YAP co-express with GFAP-positive cells in spinal cord sections which is injured for7 days,indicating that YAP is expressed in astrocytes after spinal cord injury.3.YAP co-express with Ki67 in the spinal cord section which is injured for 7 days,so the activation of YAP is associated with cell proliferation.4.We primary cultured astrocytes of rat in vitro,the expression of YAP and GFAP on protein and mRNA levels were significantly lower than the control group after the treatment with resveratrol for 48 h.5.In the rat spinal cord injury model,we choose three time spot(3 days,7 days and 28days)to explore the expression of YAP and GFAP.We found that YAP and GFAP ofspinal cord injury group which is treated resveratrol by intraperitoneal injection were significantly lower than the control group on protein and RNA levels.6.The results of rat motor function evaluation showed that the scores of the resveratrol treatment group were much higher than the control group and the naive group at each time point.Conclusions:1.In spinal cord which is not damaged,YAP is mainly expressed in neurons.After spinal cord injury,we observed that YAP is mainly expressed in activated astrocytes.2.We explored that resveratrol can inhibit the activation and proliferation of astrocytes.It is demonstrated both in vitro and in vivo experiments.Further more resveratrol also prevent the formation of glial scars on spinal cord,and promote the motor function in spinal-cord-injury rats.3.Resveratrol has a therapeutic effect on spinal cord injury by inhibiting the expression of YAP. |
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