Abstract:Objective To observe the effects of Qibai Pingfei Capsule (QPC) on serum calmodulin-2 (CAM-2) and vascular endothelial growth factor (VEGF) in rats with chronic obstructive pulmonary disease (COPD) and syndrome of stagnated phlegm obstructing lung, and to investigate its action mechanism. Methods Two hundred and eighty Sprague-Dawley rats were randomly divided into normal group (n=60), model group (n=60), QPC prevention group (n=40), QPC treatment group (n=40), nicorandil prevention group (n=40), and nicorandil treatment group (n=40). Rats with COPD and syndrome of stagnated phlegm obstructing lung were reproduced by forced swimming, fumigation, and hypoxia for 4 consecutive weeks. In the normal group and the model group, twenty rats were sacrificed at week 4, 8, or 12 of the experiment, and the serum levels of CAM-2 and VEGF were determined. In the QPC and nicorandil prevention groups, rats received prophylactic administration of drugs for 4 weeks during model establishment, and rats were sacrificed at week 4 or 8 of the experiment; the serum levels of CAM-2 and VEGF were determined. In the QPC and nicorandil treatment groups, rats received continuous administration of drugs for 4 weeks after model establishment, and 20 rats were sacrificed at week 8 or 12 of the experiment; the serum levels of CAM-2 and VEGF were determined. Results According to the results of two-way analysis of variance, two factors, model and time, had significant main effects on serum levels of CAM-2 and VEGF in rats and had significant interaction with each other (P<0.05). At weeks 4, 8, and 12 of the experiment, the serum levels of CAM-2 in the model group were significantly lower than those in the normal group (P<0.05), while the serum levels of VEGF in the model group were significantly higher than those in the normal group (P<0.05). Compared with the model group at the same time points, the QPC and nicorandil prevention groups had significantly higher serum levels of CAM-2 (P<0.05) but significantly lower serum levels of VEGF (P<0.05). Compared with the nicorandil prevention group at the same time points, the QPC prevention group had significantly higher serum levels of CAM-2 (P<0.05) but significantly lower serum levels of VEGF (P<0.05). Compared with the model group at the same time points, the QPC and nicorandil treatment groups had significantly higher serum levels of CAM-2 (P<0.05) but significantly lower serum levels of VEGF (P<0.05). At week 12 of the experiment, the QPC treatment group had significantly lower serum levels of VEGF than the nicorandil treatment group (P<0.05). Conclusion The prophylactic or therapeutic administration of QPC or nicorandil can regulate the abnormality of serum CAM-2 and VEGF in rats with COPD and syndrome of stagnated phlegm obstructing lung. QPC achieves better long-term outcomes than nicorandil.