Expression Level And Significance Of Matrix Metalloproteinase In Vascular Remodeling Of Varicose Veins Of Lower Extremities

Objective: Varicose veins(VVs)of the lower extremities is one of the common diseases in vascular surgery with relatively high incidence,but their pathogenesis is still unclear.Currently,the theory of vascular remodeling has become a new research hotspot for VVs.Matrix metalloproteinases(MMPs)are a class of peptidases widely found in the vascular wall and are secreted by various cells in the venous wall in a cryptic state,including inflammatory cells,fibroblasts and vascular smooth muscle cells.MMPs have hydrolytic activity to degrade proteins and are involved in vascular remodeling,intracellular homeostasis and adaptation in the venous system.In this study,we investigated the relationship between MMPs and TIMPs expression and venous wall dilation by examining the changes of MMPs and their tissue inhibitory factors(TIMPs)in venous tissues of lower limbs of patients with stage C1 VVs and those of patients with stage C2-3This study focused on two aspects: one was to analyze the correlation between MMPs and TIMPs and the disease progression of VVs;the other was to explore the mechanism of MMPs and TIMPs affecting VVs.VVs in relatively normal segments(root of saphenous vein)and varicose venous segments.Methods: Subgroups: Control group: Six specimens of varicose vein segments were collected from patients with VVs staged as stage C1 according to clinical,etiological,anatomical and pathophysiological(CEAP)stages.Experimental group: Varicose veins were collected from 30 patients with VVs stage C2-3,and two varicose veins were taken as experimental group.Autologous control group: The relatively normal segment of the vein(root of the saphenous vein)was collected from 30 patients in the experimental group and defined as the autologous control group.The experiment was divided into the following main parts: 96 collected specimens were stained with HE..The tissue morphology and staining effect of the stained sections were observed under a light microscope,and the extracellular matrix(ECM),vascular smooth muscle(VSMCs)and inflammatory cell infiltration of the vein wall tissue were compared among the groups.The mRNA expression of TIMP-2,MMP-2,MMP-9 and MMP-13 in the vessel wall of control,experimental and autologous control groups were detected by QRT-PCR assay.Immunofluorescence(IF)assay was performed to detect the expression rates of TIMP-2,MMP-2,MMP-9,and MMP-13 proteins in the vessel walls of the control,experimental and autologous control groups.The protein expression of TIMP-2,MMP-2,MMP-9 and MMP-13 in the lower extremity venous wall tissues of control,experimental and autologous control patients was measured by Western blot.Results:1.the stratified structure of vein wall tissues in the control group was relatively intact and the layer thickness of VSMCs was relatively moderate as observed in HE-stained sections under light microscope;compared with the control group,the autologous control group appeared to have thicker VSMCs.Some sections of the experimental group showed hypertrophy and hyperplasia of VSMCs and accumulation of ECM;some sections of the venous wall tissue had fewer VSMCs and could not form a layer,or even showed the absence of VSMCs;some sections showed infiltration of inflammatory cells.2.QRT-PCR experiments showed that the expression of TIMP-2,MMP-2,MMP-9 and MMP-13 in the experimental group was significantly higher than that in the autologous control group and the control group.The expression of TIMP-2,MMP-2,MMP-9 and MMP-13 in the autologous control group was significantly higher than that in the control group.3.Immunofluorescence(IF)assay observed that the expression rates of TIMP-2,MMP-2,MMP-9 and MMP-13 proteins in the experimental group were significantly higher than those in the autologous control group and the control group.The expression rates of TIMPs and MMPs in the autologous control group were also higher than those in the control group.4.The results of Western blot showed that the expression of TIMP-2,MMP-2,MMP-9 and MMP-13 proteins in the experimental group was significantly higher than that in the control group and the autologous control group.The expression of TIMPs and MMPs in the autologous control group was also higher than that in the control group.Conclusion: in the vein wall of patients with VVs,the difference of vein wall structure exists not only in patients with different clinical stages,but also in the vein segments with different degrees of varicose in the same clinical stage,even in the vein segments with different degrees of varices in the same patient.The expression of mRNA and protein of MMPs and TIMPs in lower extremity vein specimens of C2-3 experimental group was higher than that of self-control group and C1 control group.The expression of MMPs and TIMPs in the self-control group was also higher than that in the control group.These results suggest that ECM and VSMC are catalyzed by MMPs to cause venous wall remodeling in highly dilated veins,suggesting that MMPs and TIMPs are involved in the process of venous wall remodeling in VVs,which may be one of the mechanisms for the development of varicose veins.MMPs inhibitors can be used to prevent MMPs from binding to its substrate and degrade ECM,thereby preventing the development and recurrence of VVs.Therefore,it is of great clinical significance to find safe and effective MMP expression or activity inhibitors.