Effects Of Propofol On The Expression Of Neuronal Nitric Oxide Synthase (nNOS) In Corresponding Spinal Cord Segments After Sciatic Nerve Injury In Mice

Objective In this study,propofol was applied to mice with sciatic nerve injury to observe the expression of neuronal nitric oxide synthase?nNOS?in the corresponding spinal cord segments,and to explore the possible mechanism of propofol nerve repair.Methods Ninety-six healthy male BALB/c mice aged 8 weeks,weighing 18²2g,were randomly divided into 3 groups?n=32 each?including Sham operation group?group S?,model group?group M?and propofol group?group P?.In group S,the sciatic nerve was released from the right hip,and the nerve was not cut off,and then the incision was closed without any other treatment.Group M and group P were prepared by right sciatic nerve disconnection model.Group P was injected intraperitoneally with propofol 50mg/kg for 7 days,once a day.Group M was injected with saline of equal volume at the same time.Observe and record postoperative gait,toe syntheses and the occurrence and recovery of heel ulcer in mice.At 2W,4W and 8W after modeling,the footprint experiment was conducted to collect the footprints of mice in each group.The sciatic nerve function index?SFI?was calculated according to the formula.Eight mice were sacrificed at 1W,2W,4W and 8W at each time point.The corresponding spinal cord segments(L_4-6-6 segments)of sciatic nerve were taken from the mice.The expression of nNOS in spinal cord was detected by Western Blot method,and the expression of nNOS in spinal cord was detected by Real-time PCR.Results 1.General situation:The gait of mice in group S was about the same as that before operation,and the function of lower limbs in group S was almost normal,and there was no ulcer at heel.Mice in group M and group P were paralyzed in the right lower extremity at 1W,with unstable gait,closed toes and ulcers at the heel.At 2W³W,the mice in group P gradually recovered their paws,and the ulcer began to heal.At 7W⁸W,the toes were slightly closed,and the joint flexion disorder was improved obviously,and the ulcer healed completely.In group M,the condition of the injured lower limbs in mice did not improve at2W,and the claws were gradually restored at 4W,and the toes were together and improved,and the ulcer began to heal.At 8W,part of the ulcer was still not fully healed.2.SFI:At 2W,4W,and 8W,the SFI of group M and group P was significantly lower than that of group S?P<0.05?.At 4W and 8W,compared with group M,the SFI was significantly increased in group P?P<0.05?.3.Western Blot:Compared with group S,the expression of nNOS increased in group M and group P?P<0.05?,and decreased in group P compared with group M?P<0.05?.4.Real-time PCR:Compared with group S,the expression of mRNA increased at 1W,2W,4W and 8W after nerve injury in group M and group P?P<0.05?,and decreased significantly at four time points in group P compared with group M?P<0.05?.Conclusion The mechanism of propofol promoting the repair of peripheral nerve injury may be related to its down-regulation of nNOS expression in the corresponding spinal cord segments.