OBJECTIVETo study the role of cAMP in repair of hemisection of spinal cord in rats models.

METHODSRats models of spinal cord hemisection were made and cAMP were injected once in the motor cortex or continuously input in the lesion area or in the subarachnoid cistern for 3 d. NFs, GFAP, CSTs and spinal axons in the lesion areas were observed by immunohistochemistry and hind limb movements were evaluated in BBB scales.

RESULTSMany regenerated axons were presented in the lesion areas in cAMP groups though no continuous long regenerated axons traversed the lesion area when cAMP was input in the motor cortex or in the local lesion area. In control group, no regenerated axon were presented in the lesion areas. When cAMP was input in the subarachnoid cistern, only few-labelled CST axon survived and presented in the lesion area comparing no labelled CST axon presented in the lesion area. More NFs and less GFAP were distributed and extended in the lesion area in the cAMP groups. All the rats restored to normally walk 4-5 weeks after operations and no significance existed between cAMP groups and control groups comparing the BBB scales of hind limb movements.

CONCLUSIONcAMP injected in the brain cortex or continuously input in the lesion area can induce the axonal regeneration.