The Correlations Between Vulnerability Of Atherosclerotic Plaques And RANTES

PART I The role of RANTES as a crucial downstream cytokine in calcineurin-dependent VSMCs apoptosis stimulated by INFy and CD40LObjective:To evaluate the effects of RANTES (Regulated on Activated Normal T Cell Expressed and Secreted) on calcineurin-dependent vascular smooth muscle cells (VSMCs) apoptosis costimulated by IFN-y and CD40L (CD40 ligand).Materials and methods:VSMCs of SD rats cultured by tissue-sticking method were divided into six groups randomly. Group A was only incubated in DMEM medium for 24h; Group B and C were cultured with rat recombinant INFy (rINFy) at 20ng/ml and rCD40L at 100ng/ml for 24h, respectively; Group D was costimulated by rINFy (20ng/ml) and rCD40L (100ng/ml) for 24h;Group E was pretreated 1h with the CaN inhibitor FK506 (10ng/ml) before treatment according to group D; Group F was stimulated according to group D after transfected with the small interference RNA(siRNA) of RANTES for 6h. Expression of CD40 on the VSMC membranes in group A and B were investigated. The activity and level of CaN as well as the expression and transcription of RANTES were detected in all groups.Simultaneouly,the apoptosis rate was investigated in every group respectively.Results:The synthesis and activity of CaN as well as the expression and transcription of RANTES depended strongly on the costimulation of rINFy and rCD40L. A positive relationship was presented persistently between the rate of apoptosis and the synthesis of RANTES (P<0.01) but not CaN activity(P>0.05).Conclusion:CD40-CD40L interaction enhanced by IFN-y prestimulation induces a CaN-dependent apoptosis signal pathway in VSMCs. RANTES is a potential treating target for vulnerable atherosclerotic plaque due to its crucial downstream regulating role in the CaN-dependent VSMCs apoptosis. PART II The correlations between the expression of RANTES and apoptosis of VSMCs in atherosclerotic rabbitsObjective:To study the correlations between the expression of RANTES (Regulated on Activated Normal T Cell Expressed and Secreted) and apoptosis of vascular smooth muscle cells (VSMCs) in atherosclerotic rabbits.Materials and methods:40 male rabbits were divided into four groups randomly:(1) Blank group (n=10) and control group (n=10):received a standard diet for 16 weeks; (2)AS group (n=10) and VAP group (n=10):received a high-cholesterol diet(1% cholesterol,5% lard in rabbit food) for 16 weeks. Blank and AS groups were triggered by Russel's viper venom (RVV) and histamine at 24 and 48h before execution, control and AS groups were administered with the same dosage of sterile saline injection according to the above delivery time and location. Rabbits were euthanized at 16 weeks, blood-fat and plasma RANTES were measured in 0, 16 weeks. The transcription and expression of RANTES were calculated with Real-time PCR and Wester Blot. VSMCs apoptosis rate in plaques was detected with TUNEL and its correlation coefficients with RANTES were measured.Results:Blood-fats of high-cholesterol diet groups were high than that of standard diet groups (P<0.01). The levels of RANTES and apoptosis rates of VSMCs in AS and VAP groups increased significantly compared with that of blank and control groups (P<0.01). The distinctions of RANTES and apoptosis rates were presented between VAP and AS group (P<0.01) but not presented between blank and control group (P>0.05). VSMCs apoptosis rates were related positively with RANTES in all groups(P<0.05).Conclusion:The progression of VAMCs apoptosis may correlate with the local inflammatory reaction which induced by the overexpression of RANTES. PARTⅢThe correlations between the levels of RANTES and vulnerability of rabbit atherosclerotic plaquesObjective:To study the correlations between the levels of RANTES (Regulated on Activated Normal T-Cell Expressed and Secreted) and the vulnerability of atherosclerotic plaques.Materials and methods:40 male rabbits were divided into four groups randomly:(1) Blank group (n=10) and control group (n=10):received a standard diet for 16 weeks; (2) AS group (n=10) and VAP group (n=10):received a high-cholesterol diet (1% cholesterol,5% lard in rabbit food) for 16 weeks. Blank and AS groups were triggered by Russel's viper venom (RVV) and histamine at 24 and 48h before execution, control and AS groups were administered with the same dosage of sterile saline injection according to the above delivery time and location. Rabbits were euthanized at 16 weeks, blood-fats and plasma RANTES were measured in 0, 16 weeks. The vulnerability index and corrected plaque area were evaluated in high-cholesterol diet groups. The local transcription and expression of NF-κB and RANTES were calculated in all groups. The correlation coefficients of the vulnerability index and corrected plaque area with transcription and expression of RANTES were measured in high-cholesterol diet groups.Results:Blood-fats of high-cholesterol diet groups were high than that of standard diet groups (P<0.01). The distinction of transcriptions and expressions of RANTES and local NF-κB was not presented between blank and control groups (P>0.05). The transcriptions and expressions of RANTES and NF-κB increased gradually from Blank/Control to AS and VAP group. The vulnerability index and corrected plaque area in VAP group were high than that in AS group obviously (P<0.01). Transcription and expressions of RANTES were related positively with the vulnerability index and corrected plaque area in VAP and AS groups(P<0.05). Conclusion:RANTES levels in plasma and in lesions may promote the vulnerability of atherosclerotic plaques by NF-κB signaling pathway.