Expression of adrenomedullin and its significance in acute spinal cord injury tissue of rats

[Objective] To observe the expression of adrenomedullin(AM) in the acute injured spinal cord tissues of rats and the influences on AM expression by interference of methylprednisolone(MP) and to explore the protective mechanism in acute spinal cord injury.[Methods] Acute spinal cord injury models were established by way of Allen's WD method.The expressions of AM were observed by immunohistochemical staining and the histological changes of injured spinal cord were observed by H.E staining.MP's effects on AM's expression,neurological function and histology of injured spinal cord were also observed.The sham operation models and the injured spinal cord models without interference of MP were established as control groups.[Results] AM expressed at different levels in the spinal cord tissues of the three groups.In sham groups AM consistently expressed low.In non-interference group and MP group,the expression of AM was increased after injury.It reached peak at about 8 h,and decreased gradually later,but was significantly higher than that of sham operation group at 3 d(P 0.05).At 8 h,1 d,2 d and 3 d,the expression of AM in the MP group was higher than that of non-interference group(P 0.05).It has no significant difference at 2 h,6 d among groups.The morphologies of spinal cord tissues of the sham operation group were normal.The pathological changes in MP group were mitigated than that in non-interference group.The score of nervous condition in the sham operation group was higher than those of non-interference and MP groups(P 0.01).MP group's score was higher than no interference group's at 3,6 days(P 0.05).[Conclusion] Maybe it was one of the self-protective mechanisms in spinal cord injury that concerned with AM's increasing.To modulate the expression of AM by drug can protect spinal cord injury.It offers the evidence to use AM in clinic for SCI.