The Expression Change Of CaSR After Spinal Cordischemia-reperfusion Injury In Rats And The Role Of CaSR Inhibitor

Objective:To establish an animal model to investigate the expression of Calcium-sensing receptor(CaSR)after spinal cord ischemia-reperfusion injury in rats and the effect of CaSR inhibitors on spinal cord injury.Methods:A rat model of spinal cord ischemia-reperfusion injury was established using modified zivin method.A total of 72 SD rats,male or female,were randomly assigned to the sham operation group(n=24),spinal cord ischemia-reperfusion model group(n=24)and calcium-sensing receptor inhibitor-pretreated ischemia-reperfusion group(n=24).The sham operation group underwent laparotomy after anesthesia,but did not block the blood vessels;the model group underwent anesthesia and laparotomy,and blocked the abdominal aorta for 30 min;the inhibitor group was pre-injected with CaSR inhibitor 2 days before surgery.Each group(n=24)was subdivided into 4 subgroups(n=6)according to the gradients of 6 h,12 h,24 h and 48 h after operation,and the hindlimb function score(BBB score)was performed at the corresponding time points.Then,the expression of CaSR in spinal cord tissue was detected by immunoblotting and immunohistochemistry,and apoptosis was detected by TUNEL method.Results:1.The BBB score of the rats showed that the motor function of the hind limbs of the model group and the inhibitor group were damaged to varying degrees,and the BBB score was significantly lower than that of the sham group(P < 0.05).The scores of the sham operation group were all stable at 20 points or above,with no significant difference(P > 0.05).With the passage of time,the scores of the model group and the inhibitor group were gradually increased,but at the same time point,the scores of the model group were always higher than those of the inhibitor group(P < 0.05).2.Western blot and immunohistochemical results showed that CaSR expressionwas low in the sham group,and no difference was observed at each time point(P >0.05).Compared with the control group,both the model group and the inhibitor group had increased expression,which showed an upward trend 24 hours before and a downward trend after 24 hours(P < 0.05).CaSR expression in the model group was higher than that in the inhibitor group at the same time point(P < 0.05).3.TUNEL detection results showed that no significant positive cells were detected at 4 time points in the sham operation group;The number of positive cells in the model group and inhibitor group increased,and the number of positive cells in the two groups at 24 h and 48 h was more than 6 h and 12 h(P < 0.05).At the same time point,the number of positive cells in the model group was more than that in the inhibitor group(P < 0.05).Conclusions:1.CaSR is involved in the process of spinal cord ischemia reperfusion injury in rats,and the expression of CaSR gradually increases and reaches a peak at 24 h.2.Calcium-sensitive receptor inhibitors play a protective role in spinal cord injury by reducing the expression of CaSR,blocking the calcium overload pathway,and reducing the apoptosis of spinal cord tissue cells.