Effect of hindlimb ischemic preconditioning on expression of heat shock protein 70 in rats spinal cords following spinal cord injury / 中华急诊医学杂志

ABSTRACT

Objective To observe the effects of ischemic preconditioning of hindlimb (HIP) on the expressions of heat shock protein70 (HSP70) in spinal cord of rats after spinal cord injury (SCI). MethodSprague Dawleys rats were randomly( random number) divided into three groups (20 rats in each group).In sham injury group, rats received laminectomy without SCI; while in the SCI group, rats received traumatic SCI. In HIP group, rats received HIP 8 h before SCI. The SCI animal models were made by using modified Allen's weight-drop device (50 g·cm) on L3-L4 vertebrae. HIP was induced by compressing the two lower limbs of rats alternately with a tourniquet for three cycles of ten-minute ischaemia followed by ten-minute reperfusion. Rats were sacrificed 24 h and 48 h after injury separately. The protein and mRNA of HSP70 of involved spinal cord segments were determined by using RT-PCR, hybridization in situ and immunohistochemistry. Results There was weak expression of HSP70 mRNA in rats of sham injury group, and sporadic positive cells in spinal tissue were found by using immunohistochemistry. The expressions of HSP70 mRNA 24 h and48 hours after SCI in HIP group[(22.18±3.69) and (14.15 ±4.18)] were higher than those in SCI group[(13.97±4.46) and ( 8.73 ± 3.55 )], and the differences were statistically significant (F=16.06, P = 0.005 and F = 7.43, P = 0. 028). The protein levels of HSP70 24 h and 48 hours after SCI in HIP group [(16.71±4.02) and (9.85±2.20)] were higher than those in SCI group [( 14.85 ± 3.73)and (8.78 ±2.05)], and the differences were statistically significant (F =90. 13, P =0.032 and F=34.70, P = 0. 036). Conclusions HIP can increase the transcription and expression of HSP70 in spinal cord of rats following SCI and may have the protective effects on neural tissue.