| Purpose:Through establishing New Zealand white rabbit internal jugular vein catheterization model,to observe catheterization related intimal hyperplasia,thrombosis and fibrin sheath formation at different periods,compare the difference of intima hyperplasia in the different parts of catheterization venous and TGF-β1 expression level,and observe the related factors of secondary change in vascular after catheterization in order to provid suggestions for preventing vein stenosis.Methods:We choose the New Zealand white rabbit,a total of 50 were divided into five groups(10 for each group):normal control group,simple operation group,1,3,6 weeks indwelling groups.Normal control group which had no catheterization and was sacrificed after 6 weeks;simple operation group which those catheters were pulled out immediately after catheterization operation and sacrificed after 6 weeks;1,3,6 weeks indwelling groups were sacrificed after a indwelling period of 1,3,6 weeks respectively.All groups we took one segments of internal jugular vein for specimens,meanwhile,we took corresponding segments of the left jugular vein as the self control group from simple operation group and 1,3,6 weeks indwelling group.For each segment of internal jugular vein,we choose three sites for specimens:the catheter punctured site(site-a)、the site near the entrance of right atrium(site-b)、the midpoint between site-a and site-b(site-c).All of the vein specimens were observed in gross observation and under light microscope in HE stain,MASSON stain,TGF-β1 immunohistochemistry stain and the serum level of TGF-β1 was measured by ELISA,calculated intimal area.Result:1.Comparation among groups of different indwelling periods:(1)Gross observation:There was no thrombosis in simple operation group、normal control group、self control group,the incidence rate of thrombosis of one-week group、three-weeks group、six-weeks group were 10.0%、40.0%、70.0%,respectively,there was statistically difference between one-week group and six-weeks group(P=0.020).The incidence rate of fibrin sheath of three-weeks group、six-weeks group were 10.0%、30.0%,respectively,no statistically difference was found between this two groups(P>0.05).(2)Observation under light microscope:We could observe intimal hyperplasia in three-weeks group、six-weeks group,two forms of intimal hyperplasia could be observed in intimal layer:granule-like,papillary-like,the lumen were narrow irregularly,inflammatory cells infiltration,collagen fibers proliferation could be found,the arrangement of smooth muscle fibers was disordered,internal and external elastic layer were not continuous.While the vessel wall of normal control group、self control group were smooth,with no intimal hyperplasia and almost no inflammatory cells,no collagen fibers proliferation was found.Internal and external elastic layer were complete,no obvious fracture was found.In site-a,the intimal area among simple operation group、1 week and 3 weeks indwelling groups were greater than that of normal control group、self control group(P<0.05);there were no statistically difference of intimal area among simple operation group、1 week and 3 weeks indwelling groups(P>0.05).In site-b and site-c,the intimal area of 6 weeks indwelling group were greater than that among normal control group、self control group、simple operation group、1 and 3 weeks indwelling group(P<0.05),the intimal area of 3 weeks indwelling group were greater than that among normal control group、self control group、simple operation group、1 weeks indwelling group(P<0.05);while no statistically difference was found among normal control group、self control group、simple operation group、1 weeks indwelling group(P>0.05).(3)TGF-β1 immunohistochemistry stain:In site-a,the TGF-β1 expression in 3 weeks indwelling group were significant higher than other groups(P<0.05);the TGF-β1 expression among simple operation group、1 and 6 weeks indwelling groups were significant higher than normal control group、self control group(P<0.05);There were no statistically difference among simple operation group、1 and 3 weeks indwelling group and between normal control group、self control group(P>0.05).In site-b and site-c,the TGF-β1 expression of 6 weeks indwelling group were higher than other groups(P<0.05);3 weeks indwelling groups were significant higher than normal control group、self control group、simple operation group、1 weeks indwelling group(P<0.05);while the TGF-β1 expression of normal control group、self control group、simple operation group、1 weeks indwelling group no statistically difference could been found.2.Comparation of the secondary changes among different specimen sites:(1)Gross observation:The vessel wall in site-a of simple operation group、1 week indwelling group、3 weeks indwelling group and 6 weeks indwelling group were thickened.Thrombosis always occured in the middle of the blood vessels in 1 week indwelling group、3 weeks indwelling group and 6 weeks indwelling group,while fibrin sheath always occured in the middle and lower area of the blood vessels.(2)Observation under light microscope:We could observe intimal hyperplasia in site-a of simple operation group、1 week,3 weeks and 6 weeks indwelling groups,the arrangement of smooth muscle cell were disordered,and we could found inflammatory cells infiltration in intima and medial membrane,the collagen fibers proliferation in intima.The intima were complete in site-b and site-c of simple operation group、1 week indwelling group with no significant intimal hyperplasia or inflammatory cell infiltration or collagen fibers proliferation in intima,the internal and external elastic layer were complete,no obvious fracture was found.The vascular wall were rough in site-b of 3 weeks,6 weeks indwelling groups,and macrophages and lymphocytes infiltration were found;the arrangement of smooth muscle fibers were disordered,and internal and external elastic layer were not continuous.(3)TGF-β1 immunohistochemical stain:The TGF-β1 expression in simple operation group、1 week and 3 weeks indwelling groups,there were statistically different between site-a and site-b、site-a and site-c(P<0.05),while no statistically significant difference between site-b and site-c(P>0.05).The TGF-β1 expression in 6 weeks indwelling group were statistically different among site-a,site-c,site-b(P<0.05).3.The detection of serum TGF-β1:There was no significant difference among normal control group、simple operation group、1 week indwelling group、3 weeks indwelling group and 6 weeks indwelling group(P>0.05).4.There was significant correlation between intimal area and corresponging TGF-β1 local expression of all specimens(r=0.839,P=0.00).Conclusion:1.The degree of intimal hyperplasia become more severe as the catheter indwelling time longer,and the incidence rate of thrombosis and fibrin sheath become higher.The Temporary catheter indwelling time had better been less than three weeks in order to avoid severce venous stenosis.2.The injury simply caused by puncturing may lead to intimal hyperplasia at the puncture site easily,while the venous wall injury caused by friction of catheters was more appearent and wider,and this intimal hyperplasia become more serious as the indwelling longer.3.Venous intimal hyperplasia accompanied local high expression of TGF-β1.Hyperplasia intimal area and the local expression of TGF-β1 were positively correlated,to inhibit of the local high expression of TGF-β1 may be a therapeutic targets to alleviate intimal hyperplasia. |
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