Effects Of High Dose Methylprednisolone On Guaninenucleotide-binding Protein (G Protein) And γ-Aminobutyric Acid Transaminase (GABAT) MRNA Expression After Spinal Cord Injury

Objective: To investigate the effects of high dose methylprednisolone (MP) on guaninenucleotide-binding protein(G protein) andγ-Aminobutyric acid transaminase (GABAT) mRNA expression after spinal cord injury.Methods: Thirty SD rats were divided equally into sham surgical group, Allen's weight drop injury group and injury with high dose MP group. There is no treatment for the rats in sham surgical group, Mp(30mg/kg) was injected through the caudal vein for the rats in high dose MP group and equal dose of physiological saline for the drop injury group. 24 hours after the operation, the spinal cord injured and 0.5cm neighboring areas were harvested for examination of G protein and GABAT mRNA expression by retrograde polymerase chain reaction technique (RT- PCR) .Results: 24 hours after the operation, The relative abundance of G protein mRNA and GABAT mRNA expression of sham surgical group were respectively 0.9998±0.1763 and 0.8871±0.0162, which decreased significantly after spinal cord injury to 0.5945±0.2976 (P<0.05) and 0.2083±0.1521(P<0.01), but increased significantly after treatment with high dose MP to 1.5329±0.1548 ( P<0.01) and 1.0646±0.3057 ( P<0.01) respectively. However, for the comparison of the outcomes between injury with high dose MP group and sham surgical group, the relative abundance of G protein mRNA expression increased significantly(P<0.01), but that of GABAT mRNA expression just increased to normal level(P>0.05) .Conclusions:MP can greatly upregulate and reverse the expression of G protein and upregulate the expression of GABAT to normal level, thus protect the neighboring injured areas after spinal cord injury.