| Immunohistochemical method was used to detect the expression of Growth associated protein-43(GAP-43) and Heat shock protein27(HSP27) in the different periods after spinal cord injury(SCI); the rats were tested hind limbs motion function by Basso Beattie Bresnahan(BBB) scores evaluation during survival time; with hematoxylin-eosin(HE) staining to observe the pathological changes of injury spinal cord tissue b etween groups at different time, in order to determine whether the intrathecal injection of methylprednisolone sodium succinate(MPss) is involved in regulating the expression of GAP-43 and HSP27 in spinal cord neurons, to further clarify the possible mechanism of acute SCI repair after intrathecal injection of MPss.Ninety female rats weighing(210±10)g healthy adult rats were randomly divided into the treatment group, the observation group and the control group, thirty rats in each group. The treatment group were undergone SCI before intrathecal injection of 3 mg/kg MPss was dissolved in 0.5ml sodium chloride. The observation group received simple operation to expose the spinal cord, without spinal cord damaged. The control group were undergone SCI before intrathecal injection of 0.9% sodium chloride. Histological analys is and behavioral observation were carried through at time 1, 3, 7, 14 and 28 th day after surgury.Histology Results: the expression of GAP-43 in rat’ spinal cord injury were enhanced, but the observation group had little expression of GAP-43. GAP-43 in spinal cord treatment group and control group of intrathecal injection of MPss was highly expressed. The expression of GAP-43 was gradually increased in the 1st, 3rd, 7th days after spinal cord injured, and to the highest level in the 7th day, the expression gradually decreased. The control group was close to the observation group in the 14 th day, and they were reduced to the same level of expression of the two groups in the 28 th day, but they were still higher than the observation group. Intrathecal injection of treatment group at an early expression of the number and strength were higher than the control group, with time, down to the same level with the observation group. Image analys is showed anterior horn positive reaction after treatment group was higher than observation group in the 1st,3rd,7th,14 th days, in the 3rd day was most obvious, and the difference was significant(P <0.05). HSP27 in the observation group showed a low level of expression, but treatment group and control group were peaked at 1st day. In treatment group the number of positive cells and positive staining intensity were stronger than the control group at 1st and 3rd days, the expression was gradually declined. Treatment group and control group were close to the control group in the 7th day. Anterior horn positive reaction of treatment group was higher than control group, and in the 1st day was most obvious. The difference was statistically s ig nificant(P<0.01). HE staining results: treatment group and control group were seen tissue edema, structural disorder, lymphocyte infiltration, Nissl bodies melting and other pathological changes in the spinal cord, and the pathological changes of intrathecal injection of MPss were light to the control group. Spinal cord structure of observation group was clear and no pathological changes in cell edema. HE staining results showed that intrathecal injection of MPss reduced the pathological changes after spinal cord injury resulting behavior observation: BBB scores proved that the function of SCI rat hind limbs movements after intrathecal injection of MPss was better. The difference of treatment group and control group after surgery in the 7th, 14 th, 28 th days, were statistically significant(P<0.05). Treatment group was significantly higher than the control group in recovery of spinal cord injury.Intrathecal injection of MPSS promoted the repairing of the spinal cord injury nerve cells, and its mechanism may be associated with intrathecal injection of MPss enhanced the expression of GAP-43 and HSP27 of the injured spinal cord nerve cells. Key words:Methylprednisolone sodium succinate; Intrathecal injection;... |
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