Contribution of Heme Oxygenase 2 to Blood Pressure Regulation in Response to Swimming Exercise and Detraining in Spontaneously Hypertensive Rats
Emine Kilic-Toprak, Ozgen Kilic-Erkek, Gulcin Abban-Mete, Vildan Caner, Ikbal Cansu Baris, Gurkan Turhan, Vural Kucukatay, Hande Senol, Oktay Kuru, Melek Bor-Kucukatay
Department of Physiology, Faculty of Medicine, Pamukkale University, Denizli, Turkey
Med Sci Monit 2018; 24:5851-5859
We aimed to determine the effects of exercise followed by detraining on systolic blood pressure (SBP), heme oxygenase 2 (HO-2) expression, and carboxyhemoglobin (COHb) concentration in spontaneously hypertensive rats (SHR) to explain the role of carbon monoxide (CO) in this process.
MATERIAL AND METHODS: Animals were randomized into exercised and detrained groups. Corresponding sedentary rats were grouped as Time 1–2. Swimming of 60 min/5 days/week for 10 weeks was applied. Detraining rats discontinued training for an additional 5 weeks. Gene and protein expressions were determined by real-time PCR and immunohistochemistry.
RESULTS: Aorta HO-2 histological scores (HSCORE) of hypertensive rats were lower, while SBP was higher. Swimming caused enhancement of HO-2 immunostaining in aorta endothelium and adventitia of SHR. Exercise induced elevation of blood COHb index in SHR. Synchronous BP lowering effect of exercise was observed. HO-2 mRNA expression, HSCORE, and blood COHb index were unaltered during detraining, while SBP was still low in SHR.
CONCLUSIONS: CO synthesized by HO-2 at least partly plays a role in SBP regulation in the SHR- and BP-lowering effect of exercise. Regular exercise with short-term pauses may be advised to both hypertensives and individuals who are at risk.
Keywords: Aorta, Heme Oxygenase (Decyclizing), Rats, Inbred SHR, Swimming