Abstract: Objective To investigate the relationship between neurogenic bowel dysfunction (NBD) and substance P in rats suffering from spinal cord injury (SCI). Methods 60 male Sprague-Dawley rats, weighted (220±40) g, were randomly divided into three groups: sham group (n=20), normal group (n=20) and model group (n=20) and then were subdivided into subgroups of 24 h, 1 week, 3 weeks, and 5 weeks respectively after SCI. SCI model was established at thoracic 10 segment of rat with NYU impactor device. The colon tissue of the rats was resected and stored. Substance P in serum and tissue was measured by ELISA. The tissue was examined by real-time RT-PCR and Western blotting to analyze the expression of substance P. Results The colon intestinal transmission function decreased and delineated at minimum value at 3 weeks in the model group. There was statistical significance with respect to the content of substance P in serum and tissue between the sham group and model group at 3 weeks. The expression of substance P in the sham group was (3.12±0.51) times of the model group (P<0.05). Conclusion Substance P may take part in NBD after SCI in rats.

Key words: spinal cord injury, substance P, neurogenic bowel dysfunction, rats