Expression characters of substance P in rats with lumbar spinal stenosis cansed by cauda equina compressions model / 中国组织工程研究

ABSTRACT

BACKGROUND: As a pain-related peptide, substance P is closely related with sustained pain in low back and lower extremities caused by lumbar spinal stenosis. However, the expression of substance P in the rat with cauda equina compression rat is not reported.OBJECTIVE: To investigate the content of substance P in spinal cord of rat with lumbar spinal stenosis at different stages.DESIGN: A randomized and controlled experimental study.SETTING: The Orthopedic Department of the First Affiliated Hospital of China Medical University.MATERIALS The trial was conducted in the Experimental Animal Center of China Medical University within the period from February 2003 to December 2004. Thirty mature male SD rats were randomly and averagely assigned into five groups. One group served as control and in the other four experimental groups the content of substance P of the rats were examined in the 2nd, 4th, 8th and 12th respect week respectively.METHODS: The model of lumbar spinal stenosis was established by compressing cauda equina in rats. The spinal cords were harvested in the 2nd,4th, 8th and 12th respect week respectively for immunohistochemical determination of the expression of substance P (SP) in the posterior horn.MAIN OUTCOME MEASURES: The expression of substance P in the posterior horn at different times. Deeply-stained neurons in the 2nd week group. The mean positive neuron group varied within a certain range and were less than that of the 2nd week group. But they were all more than that of the controls[(5.08 ±0.41),(4.02±0.35), (2.58±0.33), (3.45±0.22) vs(0.85±0.23), t=6.85,5.90,3.49,6.85,P ＜0.05 or P ＜0.01].CONCLUSION: The expression of substance P increases when the cauda equina is compressed. Whether this is because the harmful stimuli increases SP expression and the latter in turn protects spinal cord by reducing the edema of spinal cord warrants more studies.