The Effect Of Cyclo-oxygenase-2 And Its Specific Inhibitor In Rats' Ventricular Remodeling

Background and ObjectiveIn recent years, the morbidity and mortality of chronic heart failure keep in increasing, furthermore, heart failure become the chief challenge of the cardiologists all over the world in the 21th century. At present, a large number of studies have shown that, the left ventricular remodeling is the basic mechanism of the development of heart failure, at the same time, cardiac hypertrophy in ventricular remodeling is an independent risk factor for cardiovascular disease. In that, to reverse the cardiac hypertrophy will have a more far-reaching significance to prevent the development of heart failure and to reduce mortality rates. However, at present, there is not any effective drug to reverse the cardiac hypertrophy, for the trearment of heart failure just to deal with more symptomatic. Past studies have shown that there are a large number of inflammation involved in the occurrence and development of cardiac hypertrophy, ventricular remodeling, and heart failure. The level of inflammatory markers, such as TNF-α,TGF-β,CRP,UA, and so on, will increase significant in hypertrophic myocardium. Protein Smad1/2/3 has promotive effect to heart ventricle remodeling, and TGF-β-SMADs pathway may be involved in the pathophysiology process of ventricular remodeling. A large number of study found that COX-2 took part in the process of ventricular hypertrophy, ventricular remodeling and heart failure. Nowadays, some scholars made some study, an found that COX-2 inhibitor can contain systolic pressure raise and ventricular hypertrophy which suffer from situations of high sodium in a long time in rats. The objective of this research is:①to study the expression of COX-2 in the development of pressure overload cardiac hypertrophy of rats in two different time spot, and then get the message of the influence of COX-2 in the process of ventricular remodeling;②to observe the change of protein Smad1/2/3 and collagen volume percentage in myocardium, to measure the level of inflammatory markers in rats'blood after using the specific COX-2 inhibitor, accordingly, to study the intervention effect between the specific COX-2 inhibitor and myocardial hypertrophy, heart ventricle remodeling, heart failure.MethodsSixty-eight healthy mail Sprague-Dawley(SD) rats were randomly divided into five groups: sham group(n=8), surgery 20 weeks group(n=15), Celecoxib 20 weeks group(n=15), surgery 24 weeks group(n=15), and Celecoxib 24 weeks group(n=15). The rats of surgery and Celecoxib groups will suffer from an operation which make the abdominal aorta narrow, and become a model with pressure overload cardiac hypertrophy; we put Celecoxib 10mg/kg into the feed evenly, and feed the rats of Celecoxib groups for 4 and 8 weeks.After 16 weeks of the operation, we chose three rats in each group randomly, and checked it with Color Doppler Flow Imagining to get the message of myocardial hypertrophy of rats. After 20 and 24 weeks of the operation, we checked the rats with Color Doppler Flow Imagining, acknowledge the items of inter-ventricular septum(IVS), left ventricle posteriorwall(LVPW), leftventricle end-diastolic diameter (LVDD), leftventricle end-systolic diameter(LVSD), and so on, and account leftventricle end-diastolic diameter(LV-FS) and ejection fraction(EF). And then, did anesthesia for the rats, took the thoracotomy to expose the heart, and then ,to puncture the left ventricle to take 5ml blood to check the inflammation maker such as TNF-α,TGF-β,PGE2,CRP,UA. After that, take out the heart, to separate the left ventricular free wall and interventricular septum as the left ventricular mass(LVM), to account the relative value of the left ventricular mass and the weight of rat(BM) as the left ventricular mass index(LVMI), and account the relative value of the weight of heart(HW) and the weight of rat at the same time. Followly, to take a half of left ventricular into a specimen bottle with formaldehyde solution and prepare to send to do the pathological examination; make the immunohistostaining and observe the expression of COX-2 in myocardium of rats; the other half was cleaned and put into a specimen bottle and then freeze in the fridge with -70℃to do Western Blot with protein Smad1/2/3. The heart collection specimens used for the pathological examination was immediately fixed in formaldehyde solution for Masson stain sections and paraffin-embedded sections; take an observation and analysis of morphology of myocardial collagen, account CVF-T and CVF-NV; the other half was put in -70℃refrigerator for Western Blot of protein Smad1/2/3.Results(1)Death of rats: The rats of sham group didn't die, and the situation of activities, eating, drinking, fur color and spirit were better than the rats of surgery groups. After feeding the rats with Celecoxib, the situation of activities, eating, drinking, fur color and spirit were better than the rats of surgery groups. The number of deaths of rats in surgery 20 weeks group, Celecoxib 20 weeks group, surgery 24 weeks group, and Celecoxib 24 weeks group were: six rats, six rats, seven rats, five rats.(2)The result of Color Doppler Flow Imagining: In comparison of sham group, the levels of IVS-d,LVPW-d were higher in surgery groups(P<0.01); the levels of FS, CO, SV, EF in surgery 20 weeks group(P for FS<0.01; P for CO,SV,EF<0.05) and the level of CO, EF, FS, SV in surgery 24 weeks group were lower(P for CO,EF,FS<0.01; P for SV<0.05). In comparison of surgery 24 weeks group, the levels of IVS-d,IVS-s,LVPW-s were lower in Celecoxib 24 weeks group(P<0.05); the levels of EF, FS, CO, SV were higher in Celecoxib 24 weeks group(P for EF, FS<0.01; P for CO, SV<0.05).(3)The result of LVMI: In comparison of sham group, the levels of LVMI and HW/BW were higher in surgery groups(P<0.05). In comparison of surgery 24 weeks group, the levels of LVMI and HW/BW were lower in Celecoxib 24 weeks group(P<0.05).(4)The result of pathology: In comparison of sham group, myocardial cell in surgery groups rats had become hypertrophy, and were surrounded by a large number of collagen, separated from each other, muscle fiber were disorder or fracture; myocardial collagen had increased, the most was in interventricular septum and endocardium. Collagen deposition around small blood vessels was much more than interstitial myocardial. Myocardial collagen was lower in Celecoxib groups. After pathological image processing(400 times) with Graphic color pathological analysis system, we accounted CVF-T and CVF-NV, the result shown that in comparison with sham group, the levels of CVF-T and CVF-NV was higher in surgery groups(P<0.01). In comparison of surgery groups, the levels of CVF-T and CVF-NV was lower in Celecoxib groups(P<0.01). In micro with 400 times, we found the expression of COX-2 increased in surgery groups, and the immunoreactivity strengthened; to compare with surgery groups, the expression of COX-2 decreased in Celecoxib groups, the immunoreactivity hypoergied, but it increased in comparison with sham group; and the change above would obvious with surgery time extension.(5)The result of inflammatory: In comparison of sham group, the levels of TNF-α,PGE2,CRP,UA increased in surgery 24 weeks group(P for TNF-α, PGE2<0.01; P for CRP, UA<0.05). At the same time, in comparison of surgery groups, the levels of TNF-α,TGF-β,PGE2,CRP,UA decreased in operated add to Celecoxib 24 weeks group(P for TNF-α, PGE2, UA<0.01; P for CRP<0.05).(6)The result of protein Smad1/2/3: In comparison of sham group, the level of Smad1/2/3 was higher in surgery groups(P for surgery 20 weeks group<0.05; P for surgery 24 weeks group<0.01). In comparison of surgery groups, the level of Smad1/2/3 was lower in Celecoxib groups(P for Celecoxib 20 weeks group<0.05; P for Celecoxib 24 weeks group<0.01). Conclusion(1)COX-2 participate in the process of ventricular remodeling and heart failure.(2)The development of myocardial hypertrophy and heart ventricular remodeling have a closed relationship with inflammation and myocardial fibrosis, and refer to the up-regulation of protein Smad1/2/3 and its.(3)The specific COX-2 inhibitor maybe can postpone the development of heart ventricle remodeling, maybe it refer to the specific COX-2 inhibitor can resist the expression of COX-2, inflammatory factor, myocardial fibrosis and restrain the expression of protein Smad1/2/3, and so on.