Compression Venous Wall Remodeling Mechanism

PARTâ… STUDY ON MORPHOLOGY OF LEFT COMMON IIAC VEIN AND IT'S CLINICAL SIGNIFICANCEObjective: To explore the possible mechanism of vascular remodeling and characteristics of biomechanics by studying the morphology and the changes of elastic compositions of the compressed left common iliac vein(LCIV) and adjacent segments.Methods: Eighty cadavers fixed with formalin(male 42, female 38)were randomly selected, the transverse diameter (wafering), the intravenous band within the compressed LCIV and angle between LCIV and RCIA (right common iliac artery) were observed and measured. The compressed segment together with its distal and proximal segments in 18 samples was then removed, dehydrated, embedded in paraffin, sliced and stained with Messon technique. As a control, the corresponding portions in the opposite side to the compressed portion were removed and the research processes were as same as above. After that the structure changes (SM, EF, CF, thickness of venous wall ) were observed and analyzed with the Beihang CM-2000B Biomedical Image Analysis System .Results: Compared with right side, the venous wall of the compressed LCIV was collapsed and its thickness became thinner (P<0.05). Compared with the proximal and distal portions compressed as well as the right, the transverse diameter of the compressed LCIV increased (P<0.01), the relative content of smooth muscles reduced and the relative content of elastic fibers and collagen fibers increased (P<0.05)Conclusions: The LCIV compressed by the RCIA results in derangement of hemodynamics , which might improve vascular remodeling development including the change of mechanic structures in the venous wall and intravenous band formation. Those changes lead to further derangement of hemodynamics and abnormity of histology. It is those transform of morphology and hemodynamics that might be the possible pathogenesis of the iliac vein compression syndrome (IVCS) and the deep venous thrombosis. PARTâ…¡THE ESTABLISHMENT OF COMPRESSED VEIN MODEL IN THE RAT AND ITS SINIFICANCEObjective: The aim of this study was to establish a model of compressed vein in rats, so as to provide a basis for further studies on the molecule mechanism of iliac vein compression syndrome (IVCS) and the pathological changes of the vein compression injury caused by other factors.Methods: Forty-eight adult SD rats were divided into 4 groups at random, and the rat left common iliac vein and artery, together with different diameter of needle, were ligated with string to compress the vein, making a model of partial vein compressing. The intravenous pressure of the compressed left common iliac vein was measured; the postoperative blood circulatory condition in the operated hind limb was observed; and the compressed segment of the vein in different time were properly taken, sliced and stained with HE or Masson; and then the pathological changes of the vein were observed;Results: Compared with control, the intravenous pressure within the compressed left common iliac vein was increased in the group gauge4.5# and group gauge 5# (P< 0.05).The operated hind limbs of rats were inactive and congested only in the group gauge4.5#. The pathological changes of the vein became more and more obvious with the duration of time. However, both of the control group and the group gauge 6#, the intravenous pressure of left common iliac vein kept unchanged.Conclusion: The results suggest that best choice of simulating vein compression model in rat might be to use gauge 5# needle for partial iliac vein ligation. PARTâ…¢CHANGES OF C-MYC AND MMP-9 EXPRESSION IN COMPRESSED COMMON ILIAC VEIN OF RATSAim: To observe the changes of c-myc and MMP-9 expression in compressed common iliac vein of rats, so as to explore molecule mechanism of vascular remodeling in the compressed vein.Methods: Forty-two adult SD rats were divided into 2 groups at random. The model of compressed vein was established by the methods established in partâ…¡(types of needle is 5# in this experiment). The compressed segment of common iliac vein, including the proximal and distal part of the vein was taken at 0.5h, 12h, 24h, 48h, 72h, 7d, 14d after compression. Immunohistochemical was used to detect the immunoactivity for c-myc and MMP-9. The integral optical density (IOD) of sections was observed and analyzed with Beihang CM-2000B Biomedical Image Analysis System.Results: There was no expression of the c-myc and MMP-9 in control group. The c-myc in the experimental group began to express at 12h after compression, and the expression of c-myc presented its peak in 7d after compression. But the expression of MMP-9 began to express at 24h after compression, and the expression of MMP-9 presented its peak too in 7d after compression. The IOD of sections was to increace gradually with the duration of time, compared with control group (P<0.05). The expression of c-myc was correlation with the MMP-9(r=0.7532,P <0.05).Conclusions: The c-myc and MMP-9 perhaps play an important role in vascular remodeling of compressed vein.