The Role And Mechanism Of Resveratrol To Protect The Spinal Cord And The Distant Organs After Spinal Cord Injury In Rats

Objective : To explore the protective effect and mechanism of resveratrol for the spinal cord and distant organs(including the lungs, kidneys, liver) after spinal cord injury in rats. And provide experimental evidence for spinal cord injury clinical drug treatment and control of complications.Methods:We established the rat spinal cord contusion model using modified Allen’ s method at T10.In the first part of the experiment,We conducted a 3-month observational study focusing on protective mechanism of resveratrol for the spinal cord after SCI. All the S-D rats were randomly divided into 4 groups:uninjured group(n=24);sham group(n=24),SCI group(n=24),SCI+ RES group(n=24)。The rats in SCI+resveratrol treated group were given resveratrol(50mg/kg) via intraperitoneal injection immediately after SCI,then they were administered RES every 24 hours, for 3 consecutive times. We conducted BBB functional evaluation, thermal contraction test of lower extremity, electrophysiological examination and MRI at 0d,3d,1W,2W and 1month. Long-term functional evaluation including BBB score, reaction time of heat pain, electrophysiological examination and MRI has obviously improved after RES treating in rats with SCI. Then we determined the expression of SIRT1, inflammatory factors, autophagy and apoptosis indicators by methods of western blot and ElISA.In the second part of our study, 64 aged rats S-D rats were randomly divided into 4groups for the investigation of the remote argans,function after SCI. The four groups werr uninjured group(n=16),SCI+VEH group(n=16),SCI group(n=16)and SCI+ RES group( n=16),respectively.The rats in SCI+resveratrol treated group were given resveratrol(50mg/kg) via intraperitoneal injection immediately after SCI. Pathological Detection, determination of inflammatory cytokines in bronchoalveolar lavage fluid, renal and liver function test, the expression of SIRT1 in lung, kidneys and liver tissue, changes ofinflammatory factors and the state of cell autophagy and apoptosis were conducted by specific methods at 12 h,24h,72 h and 7d after SCI.Results:BBB score in SCI+Res group were significantly higher than SCI group at time of 7d,2W,1month and 3month after SCI(p<0.05). Compared with SCI group, thermal contraction time of lower extremity in SCI+Res group were less than SCI group(p<0.05).Judging from the axial and sagittal plane of MRI,Res+SCI group showed a greatly improved in comparison with SCI group. SCI+Res group had a higher amplitude of evoked potentials than SCI group in electrophysiological examination at 7D,2W,1M and3M(p<0.05). TTC staining showed resveratrol can effectively improve the microcirculation and increase the oxygen in spinal cord after SCI. TNF-α, IL-6 and IL-10 increased significantlyin spinal cord tissue after SCI showed by ELISA(P<0.05).However,pro-inflammatory factors such as TNF-α and IL-6 were significantly decreased after resveratrol treatment(P<0.05). Additionally,resveratrol can suppress inflammation by reducing the expression level of neural cell adhesion molecule(NCAM)(P<0.05).Resveratrol can effectively protect and promote functional recovery through increasing the autophagy and inhibit the occurrence of apoptosis.In the second part of this study, RES+SCI group have a lower pathology score of lung,renal and liver compared with SCI group(P<0.05).SCI rats treated with resveratrol can significantly decrease the value of W/D and PPI,reduce the expression of APQ-1(P<0.05).Resveratrol also decrease the MPO activity in lung, liver and renal tissue(P<0.05).After resveratrol treating, the level of TNF-α and IL-6 in lung, liver and renal in were significantly decreased(P<0.05);the level of IL-10,an anti-inflammatory factor,was significantly increased(P<0.05). Indicated by Western Blot data,the expression of SIRT1 in lung, liver and renal tissue was significantly up-regulated in RES+SCI group(P<0.05);however,the activity of NF-κB was significantly decreased(P<0.05). In addition,resveratrol can effectively promote the occurrence of autophagy by increasing the level of AMPK and LC3-II( p <0.05) and reduce the activation level of caspase-3.Conclusions : Resveratrol can upregulate the expression of SIRT1, reduce inflammation in the injured spinal cord, neural cell adhesion molecule expression suppressed, but can also regulate autophagy and apoptosis control to protect the spinal cord,thus promoting the recovery of spinal cord injury in rats with spinal cord injury, due to thesystemic inflammatory response, have distant organs(lung, kidney, liver) caused varying degrees of damage, causing organ dysfunction. Resveratrol can increase SIRT1, reduce inflammation and promote cell autophagy inhibition of apoptosis, for lung, kidney and liver function after spinal cord injury play a protective effect, reducing the mortality rate of spinal cord injury.