The Effect Of AT1-AA On Atherosclerosis Of ApoE-knock Mice

Aim: to investigate the potential effects and molecular mechanisms of AT1-AA on the process of atherosclerosis in ApoE-/- mice. Methods: we used two strategies to establish the animal models with AT1-AA and 60 mice were divided into two groups: one was active immunization group (AIG) that the conjugated AT1 peptide was injected subcutaneously at multiple points; the other was passive immunization group (PIG) which was infused AT1-AA antibodies prepared from rabbits weekly. Each group of mice was further divided into five subgroups at random: positive groups (immunized actively with antigens or infuse antibodies, Pos), valsartan group (immunized actively with antigens or infuse antibodies, meanwhile, valsartan,(antagonist of angiotensin II type 1 receptor) was given by gastric gavage at 2mg.kg-1.d-1, V), fenofibrate group (immunized actively with antigens or infuse antibodies, meanwhile, fenofibrate, was given by gastric gavage at 30mg.kg-1.d-1, F), PDTC group (immunized actively with antigens or infuse antibodies, meanwhile, PDTC(a potent inhibitors of NF-κB), was given every other day by intraperitoneal injection, 30mg.kg-1), negative group (immunized actively with adjuvant or infuse serum proteins, Neg). All male ApoE-/- mice were given normal diet for 16 weeks, blood samples were taken at 0, 4th, 8th, 12th, 16th week after overnight fasting to monitor antibody titer by using an enzyme-linked immunosorbent assay (ELISA). The plasma total cholesterol and triglyceride concentration were measured by autoanalyzer. Plasma CRP, TNF-α, NF- B and H2O2 concentration were measured by ELISA. Atherosclerotic lesion area in arotic root was evaluated by oil red O staining. P47phox, MCP-1 and eNOS were assessed by real time reverse-transcription polymerase chain reaction (RT-PCR). P47,NF- B and MCP-1 were assessed by western blot.CCR2(the receptor of MCP-1), macrophages and smooth muscle cells assessed by immunohistochemistry. Results: AT1-AA was persistently detected in mice that treated with AT1-AA, AT1-AA plus valsartan, AT1-AA plus fenofibrate and AT1-AA plus PDTC.Moreover, there was no difference in the plasma total cholesterol and triglyceride concentration in all mice. While the mice treated AT1-AA were associated with a marked in atherosclerosis area, as well as the expressions of CRP, TNF-α, NF- B, H2O2, P47phox, MCP-1 CCR2, macrophages and smooth muscle cells. These changes were suppressed in mice treated with AT1-AA plus valsartan, AT1-AA plus fenofibrate and AT1-AA plus PDTC, moreover these three groups have revealed that valsartan, fenofibrate and PDTC could enhance the expression of eNOS in vascular tissue. Conclusion: Our study demonstrated that AT1-AA facilitates atherosclerosis, this effects is in part related to promotion of oxidative stress and inflammatory response which leads to the increase in the expression of inflammatory cytokines.