Swimming Exercise Ameliorates Hypertension-Induced Kidney Dysfunction via Alleviating Renal Interstitial Fibrosis and Apoptosis

Abstract

<b><i>Background:</i></b> Hypertensive nephropathy is one of the major causes of ESRD. Exercise has been considered a nonpathological therapy for hypertension and its complications, yet mechanisms remain unclear. We sought to investigate whether periodic swimming could ameliorate hypertension-induced kidney dysfunction and its underlying mechanisms. <b><i>Methods:</i></b> Four-week male spontaneously hypertensive rats (SHRs) were randomly divided into the hypertension group (SHR, <i>n</i> = 8) and exercise group (SE, <i>n</i> = 8, 60 min swimming/day, 6 days per week, for 8 weeks). Wistar-Kyoto rats (WKY, <i>n</i> = 8) were served as a sedentary normotensive group. Bodyweight and blood pressure (BP) were recorded weekly. After 8-week sedentary or swimming exercise, lipids profile, BUN, and Cr were measured. The renal interstitial fibrosis was examined by the histopathological analysis using Masson’s trichrome staining and hematoxylin and eosin staining. The kidney cell apoptosis was tested by TUNEL staining. The expressions of critical proteins responsible for the TGF-β1/Smad signaling of fibrosis, that is, TGF-β1, Smad2/3, and Smad7, as well as apoptosis related proteins, Bax and Bcl-2 in kidney cortex tissues were measured. <b><i>Results:</i></b> The 8-week swimming exercise reduced BP and bodyweight, lowered concentrations of BUN, and serum Cr, compared with SHR. Exercise remarkably inhibited hypertension-induced tubular degeneration, cellular cluster, and tubular cell swelling as well as glomerular degeneration in the kidney cortical tissues, attenuated renal interstitial fibrosis, and renal cell apoptosis. Moreover, expressions of TGF-β1, Smad2/3, and Bax were higher in the SHR than the WKY, which were significantly suppressed by the exercise. In contrast, hypertension-reduced expressions of Smad7 and Bcl-2 were enhanced by the swimming exercise. Strong correlations were found between kidney function indices, blood lipids, and key protein expressions. <b><i>Conclusion:</i></b> Our results demonstrate beneficial effects of the periodic swimming on ameliorating hypertension-induced kidney dysfunction highlighting the potential of swimming exercise as a nonpathological therapy for early prevention of hypertension-caused kidney diseases.

The effect of two types of diet on apoptosis indexes, lipid profile and histopathological outcome in acute kidney injury during exercise

“…In other words, exercise was able to reduce the rate of apoptosis after AKI. Swimming for 8 weeks in rats with hypertension-induced renal failure decreased Bax and increased Bcl2 [ 48 ]. Exercise before induction of renal ischemia reperfusion improved histopathological outcomes such as reduced tubular cast and dilatation post-injury [ 49 ].…”

Morphological Study of the Effect of Aerobic Exercise on Organs and Arteries in Spontaneously Hypertensive Rats

“…SHRs are commonly used models of spontaneous hypertension in rats with a systolic blood pressure range of generally 150 mmHg to 200 mmHg, whereas the mean systolic blood pressure in Wistar rats used as controls is generally 126 mmHg. The sample size calculations were based on the method in this literature [15] (α = 0.05; power = 0.9) and combined with the indicator of blood pressure (σ = 15.67; δ = 23.26) in the previous related study [14]. It was estimated that each group needed 8 rats.…”

“…A recent study showed that aerobic exercise could enhance the vasodilation of the mesenteric artery and reduce blood pressure by inhibiting the PKCα/Ca 2+ channel pathway in rats [13]. Swimming exercise could alleviate renal dysfunction in rats caused by hypertension by reducing renal interstitial fibrosis [14]. However, for cardiovascular and renal patients, it is unclear whether exercise can reverse the pathological morphological structure and reduce the risk factors for cardiovascular disease.…”

Aerobic Exercise Training Improves Renal Injury in Spontaneously Hypertensive Rats by Increasing Renalase Expression in Medulla

“…We also explored the effect of exercise on apoptosis. To assess the influence of aerobic exercise training on apoptosis, the expression of pro-apoptotic proteins (Bax and cleaved caspase-3) and anti-apoptotic protein (Bcl-2) were examined in the studied groups ( 43 ). As shown in Figure 2 , compared with the WKY-S group, oxidative stress (NOX2 and NOX4) and apoptosis (Bax, Bcl-2, cleaved caspase-3) in the kidney were markedly increased in the SHR-S group ( P < 0.05).…”