ABSTRACT
AIM:The 50-Hz magnetic field (MF) is a potential health-risk factor.Its effects on the cardiovascular system have not been fully investigated .This study was conducted to explore the effects of long-term exposure to 50-Hz MF on the cardiovascular system . METHODS:In the study , an exposure system was constructed and the distribution of 50-Hz MF was detected .Sixty-four Sprague-Dawley (SD) rats were exposed to 50-Hz MF at 100 μT for 24 weeks, 20 hours per day, while another 64 rats were sham exposed. During the exposure, blood pressure was measured every 4 weeks, and 24 weeks later, echocardiography, cardiac catheterisation and electrocardiography were performed .Moreover , heart and body weight were recorded , while haematoxylin-eosin staining and real-time PCR were conducted .RESULTS:The results showed that compared with the sham group , exposure to 50-Hz MF did not exert any effect on blood pressure, pulse rate, heart rate and cardiac rhythm.Further, echocardiography and cardiac catheterisation showed that there were no significant differences in the cardiac morphology and haemodynamics .In addition , histopathological examination showed that 50-Hz MF exposure had no effect on the structure of hearts .Finally, the expression of the cardiac hypertrophic relative genes did not show any significant differences between 50-Hz MF exposure group and the sham group .CONCLUSION: Taken together , in SD rats, exposure to 50-Hz/100-μT MF for 24 weeks did not show any obvious effects on the cardiovascular system .
ABSTRACT
BACKGROUND:Cytochrome P450 ( CYP) epoxygenases metabolize arachidonic acids ( AA) to form epoxyeicosatrienoic acids (EETs), which exert beneficial roles in the treatment of cardiovascular diseases , but little is known about its role on adventitial remo-deling.METHODS:We used C57BL/6J mice in vivo and primary rat adventitial fibroblasts ( AFs) in vitro treated with angiotensin II (Ang II) to investigate the effects of CYP2J2 gene delivery and exogenous EETs administration on adventitial remodeling .RESULTS:CYP/sEH system was found to exist in human adventitia , and involved in adventitial remodeling process .Exogenous EETs administra-tion significantly inhibited Ang II-induced AFs activation , characterized by differentiation , proliferation, migration, and collagen syn-thesis.These protective effects were partially reversed by PPARγantagonist GW9662 pretreatment or SOCS3 siRNA transfection.EETs suppressed Ang II-induced IκBαphosphorylation , subsequent NF-κB nuclear translocation via PPARγdependent signaling pathway in AFs.Additionally, EETs reduced Ang II-induced JAK2, STAT3 phosphorylation and subsequent phosphor-STAT3 nuclear transloca-tion, which were mediated by SOCS3 induction but independent of PPARγactivation.Furthermore, rAAV-CYP2J2 gene delivery re-duced vessel wall thickening , AFs differentiation , proliferation and collagen deposition in aortic adventitia induced by Ang II infusion , which were mediated by NF-κB and SOCS3/JAK/STAT signaling pathways in blood pressure-dependent and -independent manners , re-spectively.CONCLUSION:We concluded that CYP2J2 overexpression attenuated Ang II-induced adventitial remodeling via PPARγ-dependent NF-κB and PPARγ-independent SOCS 3/JAK/STAT inflammatory signaling pathways .