Exercise training attenuates cardiac inflammation and fibrosis in hypertensive ovariectomized rats

Abstract

This study investigated the effects of exercise training on cardiac inflammatory and cardiac fibrotic pathways in female spontaneously hypertensive rats (SHR), which were divided into a sham-operated sedentary hypertensive group (SHR-S), a sedentary hypertensive ovariectomized group (SHR-O), or a hypertensive ovariectomized group with treadmill exercise training (SHR-OT; 60 min/day, 5 days/wk) for 8 wk. Normotensive female Wistar-Kyoto rats (WKY) served as controls. SOD and catalase (CAT) activities were significantly increased in the SHR-OT group, when compared with the SHR-S or SHR-O groups. The protein levels of estrogen receptor (ER)-α and ER-β became decreased in the SHR-O group, when compared with the WKY or SHR-S groups, but were not changed in the SHR-OT group. The protein level of the angiotensin II type I receptor (AT₁R) was increased in the SHR-S group but did not further change in the SHR-O group, whereas it was decreased in the SHR-OT group. The inflammatory-related protein levels of TNF-α, p-NF-κB, cyclooxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS), and IL-6, as well as the fibrotic-related protein levels of transforming growth factor-β (TGF-β), p-Smad2/3, connective tissue growth factor (CTGF), tissue-type plasminogen activator (tPA), matrix metalloproteinase (MMP)-9, and collagen I were increased in the SHR-S group and increased further in the SHR-O group, whereas they were decreased in the SHR-OT group. The coexistence of hypertension and ovariectomy additively increased cardiac inflammatory and fibrotic pathways partially through hypertension-enhanced AT₁R and ovariectomy-depressed estrogen receptors. Exercise training appeared to suppress hypertensive ovariectomized heart-induced inflammatory and fibrotic pathways possibly through decreasing AT₁R but not through estrogen receptors.<b>NEW & NOTEWORTHY</b> The coexistence of hypertension and ovariectomy appeared to increase cardiac inflammatory and fibrotic pathways likely through hypertension-enhanced angiotensin II type I receptor and ovariectomy-depressed estrogen receptors. Exercise training on a treadmill could prevent hypertensive ovariectomized heart-induced cardiac inflammation and fibrosis via an inflammatory pathway [TNF-α, p-IKK-α/β, p-NF-κB, cyclooxygenase 2 (COX-2), iNOS, and IL-6] and fibrotic pathway [transforming growth factor-β (TGF-β), p-Smad2/3, connective tissue growth factor (CTGF), tissue-type plasminogen activator (tPA), matrix metalloproteinase (MMP)-9, and collagen I] possibly through decreasing angiotensin II type I receptor but not through estrogen receptors.