Neuroprotective Effect And Therapeutic Time Window Of Safflower Injection In Rabbit Spinal Cord Ischemia-reperfusion Injury

Objective: On the basis of early experiment that safflower injection can reduce the rabbit spinal cord ischemia-reperfusion injury,this study was designed to establish animal model of the spinal cord ischemia-reperfusion injury by occlusion of the rabbit abdominal aorta ,to study neuroprotective effect of Safflower injection in rabbit spinal cord ischemia-reperfusion injury, and to find the therapuetic time window in accordance with neuroprotective efficacy at different administration time.Methods: 48 New Zealand white rabbits, either male or female, 1.5-2.5 Kg of body weight,Were randomly divided into 8 groups(n=6):sham-operatedgroup(GroupA);saline group(GroupB,administration at 0 hour after reperfusion,2ml/kg iv);methylprednisolone group (GroupC ,administration at 0 hour after reperfusion, 60mg/kg iv); safflower injection groups(GroupD0h,D1h,D2h,D3h and D6h,administration at 0,1,2,3 and 6 hours after reperfusion,2ml/kg iv, Rabbits of safflower injection groups were administrated the same dose of safflower injection at 24 hours and 48 hours after reperfusion by intravenous injection respectively). Somatosensory Evoked Potential was detected before operation. Well-standardized rabbit models of spinal cord ischemia-reperfusion injury(the ischemic time 40 minutes) were made in B,C, D0h, D1h, D2h, D3h, and D6h group with Vascular folders. After reperfusing 24 hours and 72 hours, Tarlov,s motor scales and Somatosensory Evoked Potential were detected. After reperfusing 72 hours, pathological change of spinal cord,the activity of SOD in spinal cord, the content of MDA in spinal cord, Bcl-2/ Bax Immunohistochemical staining of spinal cord were evaluated.Results: (1)Compared with these of B group (saline group), the ratio of Tarlov,s motor scales (Except that of 24 hours time point), the ratio of SEP amplitude, the ratio of normal motor neuron in spinal cord,the activity of SOD in spinal cord, the content of MDA in spinal cord, the ratio of Bcl-2 Protein positive, the ratio of Bax Protein positive in D0h group show significant difference respectively; (2)Multiple Comparison in safflower injection groups:â‘ Compared with these of D3h,D6h group, Indicators of detection above in D0h,D1h,D2h group show significant difference respectively ; â‘¡Indicators of detection above in D0h,D1h,D2h group show no significant difference respectively ;â‘¢Indicators of detection above between D3h group and D6h group show no significant difference.Conclusion: (1) there is a neuroprotective effect of Safflower injection in rabbit spinal cord ischemia-reperfusion injury; Mechanism of neuroprotective effect: Safflower injection enhances antioxidant property of spinal cord tissue, inhibites lipid peroxidation of spinal cord tissue,reduces neural cell apoptosis by regulating expression of apoptosis-related gene Bcl-2/Bax. (2) Neuroprotective effect of Safflower injection in rabbit spinal cord ischemia-reperfusion injury is concernd with the administration time. There is an improvement of neuroprotective effect if Safflower injection is administrated in 2 hours after reperfusion. there exists a time window: in 2 hours after reperfusion.