The expression of bradykinin and its receptors in spinal cord ischemia-reperfusion injury rat model

Objective: To investigate the expression and time-dependent manner of bradykinin (BK) as well as its receptors (Bradykinin receptors 1 and 2, B1R and B2R) in spinal cord ischemia-reperfusion injury (SCII) in rat model. Methods: Sprague-Dawley (SD) rats were subjected to 1 h of infra-renal abdominal aorta occlusion and reperfused for 3 h to 5 d to induce SCII. The concentration of BK in serum was detected by enzyme linked immunosorbent assay (ELISA). In situ expression of BK receptors was evaluated by immunochemistry and their mRNA level was evaluated by Real time quantitative-PCR (RTq-PCR). Results: The concentration of BK in serum was increased right after following SCII. Both of the BK receptors were detected and up-regulated in 24 h and 48 h after injury. The levels of B1R and B2R mRNA were up-regulated after SCII, and the B1R mRNA dropped to basal level after 6 h, but B2R mRNA dropped to lower level right after injury, peaked at 3 h, then remained a lower level from 6 h till 5 day. Conclusion: This study provides the evidence of the expression of BK and its receptors in SCII in rat model, and suggests that BK and its receptors may have some physiological or pathological significance in SCII.