Abstract: Abstract: Objective: To study the role of peroxisome proliferator-activated receptor-α (PPAR-α) signal transduction pathway in cardiomyocyte hypertrophy induced by angiotensin Ⅳ (Ang Ⅳ). Methods: The cardiomyocyte hypertrophic responses were assayed by measuring the cell surface area, protein content, and atrial natriuretic factor (ANF) mRNA expression. In cultured cardiomyocytes, fenofibrate (FF), a selective PPAR-α agonist, and MK886, a selective PPAR-α antagonist, were used to investigate the mechanisms of Ang Ⅳ. The expressions of mRNA and protein were assayed by Real-time PCR and Western blot, respectively. Results: In cultured cardiomyocytes, Ang Ⅳ (0.01, 0.1, 1 nmol/L) can induce cardiomyocyte hypertrophy in a concentration-dependent manner. Meanwhile, the expressions of PPAR-α mRNA and protein decreased significantly. FF at 0.3 μmol/L increased the expressions of PPAR-α both mRNA and protein (P <0.01). All of these effects of FF could be abolished by MK886 at 0.3 μmol/L (P<0.05). Conclusion: PPAR-α signal transduction pathway involves in cardiomyocyte hypertrophy induced by Ang Ⅳ.

Key words: Key words: Angiotensin Ⅳ, Peroxisome proliferator-activated receptor-α, Cardiomyoeyte hypertrophy