Peroxisome proliferator-activated receptor-gamma in the regulation of inflammatory reaction in rats with myocardial hypertrophy

Yong WANG; Yingbin XIAO

ABSTRACT

BACKGROUND:

Peroxisome proliferator-activated receptor-gamma(PPAR-γ) can restrain the inflammatory reaction of hypertrophic myocardium through restraining the expression of interleukin-6, cyclooxygenase, endothelin-1, nitricoxide synthase, matrix metalIoproteinase-9, gelatinase and adhesion molecule, etc.

OBJECTIVE:

To observe the influence of rosiglitazone sodium(the ligand for PPAR-γ) on inflammatory factors in rats with myocardial hypertrophy in the course of myocardial hypertrophy resulting from pressure load.

DESIGN:

Randomized controlled trial based on animals.

SETTING:

Department of Cardiovascular Surgery, Xinqiao Affiliated Hospital, the Third Military Medical University of Chinese PLA.MATERIALS Fifty purebred male SD rats of S.P.F. Grade, whose body mass was (220±22) g.

METHODS:

The experiment was completed in the Institute of Battle Surgical Research, the Third Military Medical University of Chinese PLA from August 2004 to October 2005. Fifty rats were randomly divided into 5groups control group, sham operation-normal saline group, sham operationrosiglitazone group, myocardial hypertrophy-normal saline group and myocardial hypertrophy-rosiglitazone group, 10 rats per group. The rat model of myocardial hypertrophy induced by pressure overload was established with the method of coarctation of abdominal aorta. Rosiglitazone group At the postoperative 4th week, the rats were injected intraperitoneally with the Normal saline group At the postoperative 4th week, the rats were injected intraperitoneally with normal saline[1 mL/(kg.d)] for 1 week. At the postoperative 5th week, the indexes of myocardial hypertrophy and hemodynamics were determined. The contents of tumor necrosis factor-α, platelet activating factor and myeloperoxidase in the left ventricle muscle were determined with radioimmunosorbent technique. The expression of PPAR-γ mRNA was detected with RT-polymerase chain reaction. The activity of nuclear factor-κB was detected with EMSA.MAIN OUTCOME

MEASURES:

The indexes of hemodynamics, cardiac ventricle reconstitution and cardiac muscle in the rat models.

RESULTS:

Except 1 rat in the control group died of the external injury induced by biting after 3 weeks, 49 of 50 rats entered the result analysis.①After the coarctation of aorta, the contents of tumor necrosis factor-α, platelet activating factor and myeloperoxidase of hypertrophic myocardium in the myocardial hypertrophy-rosiglitazone group were lower significantly than those in the myocardial hypertrophy-normal saline group(P ＜ 0.01-0.05), but they were still higher than those in the control group(P＜0.01).②The expressions of PPAR-γ mRNA of myocardial tissue in both the myocardial hypertrophy-rosiglitazone and myocardial hypertrophy-normal saline groups were higher obviously than those in the control group(P＜0.01), and those in the myocardial hypertrophy-rosiglitazone group were higher than those in the myocardial hypertrophy-normal saline group(P＜0.01).③The activity of nuclear factor-κB combined with DNA in cardiac muscle cell in both the myocardial hypertrophy-normal saline and myocardial hypertrophy-rosiglitazone groups were higher obviously than those in the control group (P＜0.01), and those in the myocardial hypertrophy-rosiglitazone group were lower obviously than those in the myocardial hypertrophy-normal saline group(P＜0.01).

CONCLUSION:

The increasing of pressure load induces myocardial hy pertrophy. The activation of nuclear factor-κB in the tissue of hypertrophic myocardium is strengthened obviously. The expressions of tumor necrosis factor-α, platelet activating factor and myeloperoxidase in hypertrophic myocardium increase. This inflammatory reaction, which is strengthened obviously, can be restrained by rosiglitazone sodium that is the synthetical lig and for PPAR-γ.