Folic Acid Can Reduce Hyperhomocysteinemia-induced Vascular Damage by Immune/Inflammatory Response in Spontaneously Hypertensive Rats

Abstract

Background Hypertension associated with hyperhomocysteinemia (HHcy) is correlated with a high risk of vascular diseases. However, the mechanisms of HHcy-associated hypertensive vascular damage and the efficacy of folic acid (FA) as a treatment have not been fully elucidated. The aim of the present study was to evaluate the role of immune/inflammatory molecules and oxidizing factors in HHcy-associated hypertensive vascular damage, and to observe the intervention effect of FA on the two vascular injury factors. Methods Wistar-Kyoto rats (WKYs) and spontaneously hypertensive rats (SHRs) were administered DL-Hcy intraperitoneally to mimic HHcy and hypertension associated with HHcy for 12 weeks. WKYs and SHRs were randomized into WKY group, HHcy group, SHR group, SHR + HHcy group and SHR + HHcy + FA group. Mean tail artery blood pressure, plasma Hcy, serum SOD and MDA of rats in each group were compared. The thoracic aorta and bilateral carotid artery of rats were harvested for morphometric and immunostaining analyses. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to detect the expression of immune/inflammatory molecules such as TNF-α, IL-6, NF-κB p65/Rela and NF-κB2 and oxidative factors such as Nox2 and Nox4. Results We found that vascular inflammatory factors of vascular adhesion protein-1 (VAP-1), interleukin-6 (IL-6), and nuclear factor-κ-gene binding (NF-κB) p65/Rela in HHcy-associated hypertensive rats were significantly higher than those in SHRs (P༜0.05). While the oxidative stress indicators of Nox2 and Nox4 in HHcy-associated hypertensive rats were not significantly higher than those in SHRs (P༞0.05). Compared with SHRs, FA intervention in HHcy-associated hypertensive rats significantly increased serum superoxide dismutase (SOD) levels (P = 0.000) and significantly reduced vascular inflammatory factors of IL-6 and NF-κB p65/Rela (P༜0.05), but did not significantly change the oxidative stress indicators of Nox2 and Nox4 (P༞0.05). Conclusions HHcy-induced immune/inflammatory response plays a dominant role in vascular damage of HHcy-associated hypertensive rats. In addition to reducing the negative effects of HHcy, FA might involve unique antioxidant effects and inhibition of immune/inflammatory overreaction for HHcy-associated hypertensive rats.