[Effects of high dose methylprednisolone on cell apoptosis and Bcl-2 expression after acute spinal cord injuries in rats].

OBJECTIVE: To investigate the effect of high dose methylprednisolone (MP) on cell apoptosis and Bcl-2 expression after acute spinal cord injury (ASCI). METHODS: The 48 female rats were randomly divided into two groups:control group and experimental group. The spinal cord of rats were wounded at the level of T9,10 in moderate degree for each group. Thirty minutes after ASCI, the subjects in experimental group received MP injection through intraperitoneal with dosage of 30 mg/kg. Then a dosage of 5.4 mg/kg of MP was given through intraperitoneal injection every hour in 24 hours. The subjects in the control group received Normal Saline instead of MP with the same method. The impaired spinal cords were harvested on 4 h, 8 h, 1 d, 3 d, 7 d and 14 d after injury,and at each time point 4 rats were sacrificed in each group. The terminal deoxynucleotidal transferase-mediated DUTP-biotin nick end labeling (TUNEL) and immunohistochemical measurement were used to observe neural apoptosis and Bcl-2 expression. RESULTS: Apoptosis cells were noted primarily at 4 h after injury, with a maximum presence in lesion center at 8 h. The apoptotic index of MP-treated group had distinctly less than that of control group in 8 h, 1 d and 3 d after trauma. The Bcl-2 increased in the experimental group. CONCLUSION: The administration of the high dose methylprednisolone (MP) can inhibite the apoptosis after acute spinal cord injury in rats and increase the expression of Bcl-2.