| Objective: In study of atherosclerosis, extracellular matrix of plaque is closelyrelated to the evolution of AS ,the balance of MMPs and TIMPs is very important to maintain the dynamic equilibrium of ECM, and the creation of appropriate animal models of AS is the important prerequisite for studying pathogenesis of AS and therapeutic programs. In this experiment based on main three pathogenesises of AS,we established and compared with three methods of rat AS models; at the same time,basing on these models, we probed into the relationship between dynamic equilibrium of MMP-9/TIMP-1 and AS,studied the relationship between AngII( blood vessel and plasm) and AS ,and did researches on the effects of AT1 blockade losartan on anti-atherosclerosis and its mechanism.Methods: 1 To establish rat AS models, rats in the experiment were divided intofive groups: normal control group, hyperlipidemia group (fed with high-cholesterol diet), hyperlipidemia + vitaminDS group, hyperlipidemia + vitamin D3 + endothelium denudate group,losartan group (hyperlipidemia +vitamin D3 + endothelium denudate group treated with losartan).After 90 days, blood was drawn from abdominal aortas to separate serum for quantitation of serum lipids and calcium. Hematoxylin-eosin(HE) staining was used to observe the structure changes of thoracic aorta,and immunohistochemistry assay was used to observe CD68 and a-actin expression of thoracic aorta. 2 Applying the methods of immunohistochemistry western-blot zymography and RT桺CR,in full models of rats AS lesion,we observed changes of MMP-9 and TIMP-1 expression(mRNA, protein,and activity) and changes of MMP-9 and TIMP-1 expression(mRNA, protein,and activity) in losartan group, in addition, we also observed whether losartan functions as anti-atherosclerosis. 3 To study therelationship between Angll and severity of AS, radio-immunity analysis was used to assay Angll of each group, and the thickness of intima was used as the index of AS severity.4 In vitro,the rat VSMC was seperated and cultured. Furthermore,by westernblot zymography and RT-PCR analysis, the effects of expression (mRNA,pr otein,and activity)of MMP-9 and TIMP-1 on stimulating factors (different concentrations of Angll, losartan,and both of them )in VSMC were observed.Result: 1 The levels of serum total cholesterol (TC), triglyceride (TG), LDL-C inthree groups(hyperlipidemia group,hyperlipidemia + vitamin D3 group, and hyperlipidemia + vitamin D3 + endothelium denudate group)were obviously higher than those in control group (P<0.01). The levels of serum calcium in two groups(hyperlipidemia + vitamin D3 group and hyperlipidemia + vitamin D3 + endothelium denudate group)were also obviously higher than those in control group and hyperlipidemia group (P<0.01). The pathologic observation of aotic atherosclerotic lesion showed that there is no difference between control group and hyperlipidemia group,that intima thickens,forming AS plaque with VSMC proliferation in hyperlipidemia + vitamin D3 group. There were thicker intima, thinner media and formation of classic AS plaque in hyperlipidemia + vitamin D3 + endothelium denudate group.By immunohistochemistry,the CD68 positive level gradually increased with the progress of AS, a-actin positive level indicated that the thickness of media become thin in hyperlipidemia + vitamin D3 group and hyperlipidemia + vitamin D3 + endothelium denudate group.2 By immunohistochemist western blot zymography and RT-PCR analysis, MMP-9, TIMP-1,and MMP-9/TIMP-1 gradually increase as AS advances,but MMP-9/TIMP-1 in hyperlipidemia + vitamin D3 group is lower than that in other groups. Compared with positive control group(hyperlipidemia + vitamin D3 + endothelium denudate group),thickness of intima apparently decreased in losartan groups, MMP-9 decreasing,TIMP-l increasing,and MMP-9/TIMP-1 decreasing apparently.3 As AS advanced,AngII of thoracic aorta gradually increased ,serum Angll did not change. Angll of thoracic aorta has positive relation with the thickness of intima (P<0.01). 4,By...
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