1. Monocrotaline-induced Exercise-induced Pulmonary Hypertension Rat Model Establishment And Tadanafil Intervention Effect 2. Research On The Duration Of Physical Activity And The Prevalence Of Hypertension In The Young And Middle-aged In Chongqing

Background: Early symptoms of pulmonary hypertension(PH)are concealed and atypical,PH is difficult to diagnose in the early stage.Most patients with PH are already in the advanced stage of the disease or right heart failure when they are diagnosed,with an extremely poor prognosis.Aim : The aim of this study was to establish an exercise induced pulmonary hypertension(Ei PH)model in rats,to explore a viable method for the diagnosis of PH in early stage,to provide the effect of early treatment,and to assess the progression,pulmonary artery remodeling and survival of PH in rat model.Methods: Male Sprague Dawely(SD)rats,weight 200-220 g,were intraperitoneally injected with one dose of monocrotaline(MCT,60 mg/kg)or a same volume of saline.After MCT injection,the rest mean pulmonary artery pressure(m PAP)and exercise maximum m PAP(m PAPmax)was measured on the 1st,3rd,5th,and 7th day by using right heart catheter,respectively.Rats with resting m PAP < 25 mm Hg and m PAPmax > 30 mm Hg while exercise were defined as Ei PH group.In the Ei PH group,rats were given tadalafil(T,9 mg/kg)by gavage for two weeks at the 7th day after the injection of MCT;rats with resting m PAP ? 25 mm Hg were randomly separated into rest PH(r PH)group and PH group.Rats in r PH group were given tadalafil from the 21 st day after MCT injection for twoweeks.Echocardiography was employed at the 35 th day after MCT injection to evaluate the structures and function of the great vessels and heart in each group.Right heart catheter was performed to measure the pulmonary artery pressure,the heart and lung were flashed with phosphate buffered saline and removed after the pressure measurement was completed.Results: On day 7 after MCT injection,the m PAPmax was higher in MCT group than that in the control group while running on the treadmill(MCT group vs control group: 38.5 ± 2.7 mm Hg vs 27.24 ± 0.46 mm Hg,P< 0.0001).Rats in the Ei PH+T group had low m PAP(Ei PH+T vs r PH+T group: 26.67 ± 0.11 mm Hg vs 35.23 ± 0.47 mm Hg,P < 0.0001)and right ventricular hypertrophy index(Ei PH+T vs r PH+T: 0.34 ± 0.01 vs 0.46 ±0.02,P = 0.0038).The percentage of pulmonary artery wall thickness(Ei PH+T group vs r PH+T group: 44.4% vs 55.6%,P = 0.0081)was significantly lower than that of r PH+T group;Ei PH+T group had higher cardiac output than r PH+T group(Ei PH+T group vs r PH+T group: 63.89± 3.9 m L/min vs 49.03 ± 1.4 m L/min,P = 0.0088).The median survival time of rats in Ei PH+T group and r PH+T group was 29 days and 28 days after MCT injection,respectively.The survival rate between these two groups had no differ(Ei PH+T group vs r PH+T group: 0.44 vs 0.17,P =0.06).Conclusions: The study successfully established the Ei PH of rat model,identified that the invasive exercise test can be used to diagnose MCT-induced PH at early stage in rat model.With the treatment of tadalafil at early phase of MCT induced PH in rat model,Ei PH+T group,the antihypertensive effect and inhibition of pulmonary vascular remodeling were significantly improved than a late phase treatment with a same dose of tadalafil in r PH group.This result provides a new avenue forthe early diagnosis and treatment of PH and mechanism study of PH in pathophysiology.Introduction: Physical inactivity is known to cause many healthy problems globally each year.However,evidence regarding the interaction between excessive physical activity and blood pressure in young and middle-aged populations is limited.Material and methods: A multistage,stratified,random cluster sampling scheme was adopted to recruit representative samples.Participants were asked to complete a questionnaire and undergo physical examinations.Associations between prehypertension,hypertension and physical activity durations were examined by multivariable logistic regression.Results: Overall,8206 subjects(4110 men,50.1%)aged 15-45 years were enrolled.The prevalence rates of prehypertension and hypertension were 45.7% and 5.0%,respectively.Among the 1913 participants who performed moderate-intensity physical activity for more than 700minutes/week,118 had hypertension(6.2%)and 845 had prehypertension(44.2%).Among the 1003 participants who performed vigorous-intensityphysical activity for more than 450 minutes/week,82 had hypertension(8.2%)and 479 had prehypertension(47.8%).Conclusion: Long-term and sustained physical activity may increase the risk for hypertension in young and middle-aged subjects.An appropriate recommendation of PA duration should be encouraged in this cohort.