[Effects of telmisartan on endoplasmic reticulum stress induced cardiomyocyte apoptosis in abdominal aortic banded rats].

OBJECTIVE: To investigate the effects of telmisartan on endoplasm reticulum (ER) stress signal pathways and cardiomyocyte apoptosis in abdominal aortic banded rats.

METHODS: Male SD rats were randomly divided into sham-operated group, abdominal aortic banding group (AAB) and AAB + telmisartan (5 mgxkg(-1)xd(-1) per gavage, beginning at 1 week before AAB for 8 weeks, n = 10 each). Ten weeks post AAB, hemodynamic measurements were performed, whole heart and left ventricular weights were obtained, cardiomyocyte apoptosis was measured by TUNEL method. Myocardial GRP78 and CHOP protein expressions were detected by Western blot and immunohistochemistry.

RESULTS: The ratio of left ventricular weight to body weight, the ratio of heart weight to body weight, left ventricular end diastolic pressure and the apoptosis index were significantly increased while left ventricular end systolic pressure and +/- dp/dt(max) were significantly decreased in AAB group than those in sham-operated group (all P < 0.01), these changes could be significantly attenuated by telmisartan (all P < 0.01). Moreover, myocardial GRP78 and CHOP expressions were significantly upregulated in AAB group than those in sham-operated group and telmisartan could significantly downregulate the increased GRP78, CHOP expressions (all P < 0.01).

CONCLUSIONS: Increased ER stress might be responsible for enhanced cardiomyocyte apoptosis in AAB rats. Telmisartan effectively attenuated the cardiomyocyte apoptosis and cardiac hypertrophy in AAB rats possibly through reducing ER stress.