Objective: To investigate the changes in transcription and expression of inducible nitric oxide synthase (NOS2) in the liver ischemic preconditioning (IP), and to determine the role of nitric oxide (NO) synthetic pathway in the liver IP in rats.
Methods: We randomly divided 131 Sprague Dawley rats into 3 groups: ischemia/reperfusion (I/R) group (n=52), IP group (n=41), and sham operation (S) group (n=38). Plasm NO concentration and the transcription and expression of NOS2 were detected 2 hours, 24 hours, and 1 week after the operation.
Results: (1) In the IP group, the NO concentrations at the 2nd hour, the 24th hour, and 1 week were significantly higher than those in the S group (P < 0.05, P < 0.01, P < 0.01, respectively) and the NO concentrations at the 2nd hour and the 24th hour were obviously higher than those in I/R group (all P < 0.01). In the I/R group, the NO concentration at the 2nd hour was significantly lower than that in the S group (P < 0.05); there was no significant difference between the I/R group and the S group 24 hours after the operation (P > 0.05), and the NO concentration 1 week after the operation was obviously higher than that in the S group (P < 0.05). (2) In the IP group, the transcription of NOS2 2 and 24 hours after the operation were significantly increased compared with that in the I/R group (all P < 0.05) , but after 1 week, the transcription was not statistically different between the IP group and the I/R group (P > 0.05). (3) In the IP group, the expressions of NOS2 after 2 and 24 hours were obviously higher than those in the I/R group (P < 0.05) and the S group (P < 0.05), but the expression between the IR group and the S group was not significantly different (P > 0.05); after 1 week, the expressions of NOS2 in IP group and I/R group were weakly positive (P > 0.05) , and those in S group were negative (P > 0.05). Conclusion The transcription and the expression of liver NOS2 increase after the liver received ischemic preconditioning in rats. That the peak phases of transcription and expression of NOS2 are ahead of time may be related to the early protective effect of the liver IP.