Intermittent Exercise Improves Myocardial Interstitial Fibrosis in Spontaneously Hypertensive Rats Through TGF- Beta 1Smad3 Pathway

  • Maomao Zhang
Keywords: Intermittent Exercise, Spontaneous Hypertensive Rats, Myocardial Interstitial Fibrosis, TGF- Beta 1Smad3


Myocardial fibrosis is a myocardial remodeling characterized by excessive proliferation of cardiac
myofibroblasts, massive deposition of collagen fibers and abnormal distribution. It is closely related to
hypertension, chronic heart failure, dilated cardiomyopathy, viral myocarditis and other cardiovascular diseases,
and is a potential risk factor for sudden cardiac death. At present, the pathogenesis of myocardial fibrosis is not
very clear. Intermittent exercise can effectively reduce the risk factors of cardiovascular disease, reduce the
incidence and mortality of cardiovascular disease. The purpose of this study was to observe the effects of
intermittent exercise on myocardial stromal morphology and TGF- beta-1smad3 signaling pathway in
spontaneously hypertensive rats. In this paper, 8 SPF grade male WKY rats were selected as the normal control
group (group C). Twenty SPF grade spontaneous hypertension rats were randomly divided into model group
(group H) and SHR+ exercise group (group EH), with 10 rats in each group. The rats in the exercise group
received 12 weeks of swimming training without weight, 6 days a week and 1 day of rest. The first week was
adaptive training, and the exercise time of 60min/d was maintained from the second week to the end of the 12th
week. CVF%, colI and colIII were detected after the intervention period. Cardiac Smad3 was detected by qrt-pcr,
AngII by radio immunoassay, and NOX2, TGF- beta 1 and HSP90 protein expressions were detected by
western-blot. The results showed that CVF%, colI, colIII, plasma AngII, myocardial AngII, myocardial NOX2,
TGF- beta 1, Smad3mRNA and HSP90 were significantly increased in group H compared with group C (P<0.05
or P<0.01). Compared with group H, the expression of HSP90 protein in myocardium in EH group was
significantly increased (P<0.05), and all other indexes were significantly decreased (P<0.05 or P<0.01).
Conclusion: swimming exercise can significantly reduce the expression levels of colI and colIII proteins and
improve myocardial interstimal fibrosis in SHR rats, mainly by reducing angii-mediated NOX2 expression and
inhibiting the activation of the downstream TGF- beta 1/Smad3 pathway, in which HSP90, as its upstream
factor, may play an important regulatory role.