Objective: To observe the effect of mesenteric lymph duct ligation on nitric oxide (NO) and its expression in lung in rats with serious hemorrhagic shock at different periods, and explore the role of intestinal lymphatic pathway in acute lung injury (ALI).
Methods: Seventy-eight male Wistar rats were randomly divided into the sham operation group (n=6), shock group (n=42), and ligation group (n=30). The model of serious hemorrhagic shock was reproduced in shock group and ligation group. Mesenteric lymph was diverted by ligating mesenteric lymph duct in ligation group after resuscitation. All rats were executed and their lungs were harvested. NO and nitric oxide synthase (NOS) were determined in lung homogenate 90 minutes after shock, and 0, 1, 3, 6, 12 and 24 hours after resuscitation. The expression of inducible nitric oxide synthase (iNOS) mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR).
Results: The content of NO, activity of NOS and expression of iNOS mRNA in lung tissue in shock group were increased 3 hours after transfusion and resuscitation, and they became higher 6-12 hours after resuscitation. The values were significantly higher than those in sham operation group, 90 minutes after shock and 0 hour after transfusion and resuscitation (P<0.05 or P<0.01). The values were only increased 3 hours and 6 hours after transfusion and resuscitation, and all the values on 6, 12 and 24 hours after resuscitation were significantly lower in the ligation group compared with those in shock group at the same time points (P<0.01 or P<0.05).
Conclusion: The results demonstrate that the ligation of mesenteric lymph duct could reduce the NO and expression of iNOS mRNA in the lung tissue, thus ameliorate ALI in rats with serious hemorrhagic shock. Mesenteric lymph might play an important role in the pathogenesis of ALI.