ABSTRACT
<p><b>OBJECTIVE</b>To explore the partial action mechanism and the myocardial protective effect differences between electroacupuncture (EA) preconditioning at "Neiguan"(PC 6) and "Taiyuan"(LU 9) in rats with acute myocardial ischemia-reperfusion injury.</p><p><b>METHODS</b>Ninety-six Wistar rats were randomly assigned into a sham-operation group, a model group, a Neiguan group and a Taiyuan group, 24 rats in each one. The rats in the Neiguan group and Taiyuan group were treated with EA (2 Hz in frequency, 1 mA in intensity) at "Neiguan" (PC 6) and "Taiyuan" (LU 9) respectively, 20 min per treatment, once a day for consecutive 7 days. The rats in the sham-operation group and model group were treated with immobilization for the same time, and no EA was given. The model of myocardial ischemia-reperfusion injury was established in the model group, Neiguan group and Taiyuan group 24 h after the end of EA, while the rats in the sham-operation group were treated with sham operation (no ligation was made during surgery). The myocardial ischemic size, infarction size, activity of protein kinase C (PKC) and expression of aquaporin1 (AQP1) in each group were detected.</p><p><b>RESULTS</b>Compared with sham-operation group, the myocardial ischemic size, infarction size, AQP1 expression and PKC activity in the model group were significantly increased (all<0.01); compared with the model group and Taiyuan group, the myocardial ischemic size, infarction size, PKC activity and AQP1 expression were significantly decreased in the Neiguan group (<0.01,<0.05). By Pearson correlation analysis, the changes of AQP1 expression were positively correlated with those of PKC activity after EA preconditioning.</p><p><b>CONCLUSIONS</b>EA preconditioning at "Neiguan" (PC 6) could significantly decrease myocardial AQP1 expression and PKC activity in rats with acute myocardial ischemia-reperfusion injuing, but the effect of EA preconditioning at "Taiyuan"(LU 9) is not obvious; its protective effect is likely to be achieved by inhibiting PKC activity and AQP1 expression.</p>
ABSTRACT
Objective To determine if aquaporin1 ( AQP1) and aquaporin5 ( AQP5) are expressed in the alveolar-capillary membrane in rats, and to investigate the changes of AQP1 and AQP5 expression in the rat with acute lung injury.Methods The distribution of AQP1 and AQP5 in alveolar capillary membrane was investigated by immunohistochemistry and immunoelectron microscopy with affinity-purified antibodies to human AQP1 and AQP5.The possibility that alveolar capillary membrane AQP1 and AQP5 undergo altered regulation was studied by a rat model established using intra-tracheal instillation of lipopolysaccharide (LPS).Results Immunolabelling showed that AQP1 was stained primarily in the microvascular endothelium of normal lungs, while AQP5 was expressed in type I pneumocytes. Immunohistochemical analysis showed a significant decrease in the expression of AQP1 and AQP5 in injured lungs at 4 -48 h after LPS instillation.AQP1 protein was resumed partly at 24 h after LPS instillation and steroid administration, whereas AQP5 was unchanged.Conclusions The decreased expressions of AQP1 and AQP5 in injured lungs suggest that both of them may play a role in abnormal fluid transportation.