Impact Of Vincristine On The Expression Of Integrin α_v And Collagen Metabolism In The Kidney Tissue Of Diabetic Rabbit

It has been proved that inflammation has an effect on the development of diabeticnephropathy (DN). First, both the hyperglycemia and abnormal hemadynamics in DN candamage the innate cells in kidney. The damaged cells will release pro-inflammationmediator which will result in the infiltration of monocyte/macrophagocyte in kidney tissueand release tumor necrosis factorα(TNF-α).These cytokine will make the inflammationeven worse and stimulate mesangial cells to secrete type â…£collagen and laminin (LN)which will cause glomerulosclerosis. Second, damaged glomerular will lead to the increaseof filtered protein. The filtered pro-immune mediator will stimulate the tubular epithelialcells to secrete immune mediator and cytokine which cause the aggregation of interstitialmonocyte/macrophagocyte, proliferation of mesangial cells and myofibroblast which lead tointerstitial fibrosis. Because of the abnormal cell cycle in DN, the tubular epithelial cellsand mesangial cells will be hypertrophy after they finish the limited proliferation.Interstitial fibroblast and endotheliocyte in glomerulus will keep on the proliferation. Theseenlarged cells will secrete more extracellular matrix(ECM), which causes the volumeexpansion of kidney. As a kind of specific medicine for cell cycle, VCR plays a veryimportant role in inhibiting the proliferation of cells in M period. It may suppress theproliferation of innate cells in kidney.At present, the methods of clinical therapy for DN are mainly the following: controlblood glucose and pressure, reduce hyperlipoproteinemia. The effect of these methods arelimited. Every year many patients of DN who are at the end stage renal disease(ESRD) haveto count on dialysis to keep alive. Although it is realized that inflammation plays animportant role in the development of DN, there are few anti_inflammation researches forDN at home and abroad. Pujikara pointed out in his paper on Kidney International in 2003,that mycophenolate mofetil(MMF) can delay the development of experimental diabetic ratsnephropathy caused by STZ by means of anti_inflammation functions such as inhibiting theproliferation of monocyte/macrophagocyte and limiting the expression of adhesionmolecule. As VCR has the function of immunodepression and resisting the aggregation ofplatelet, it has been used in the therapy of nephritic syndrome and lupus nephritis, andtherefore we make researches on the impact of VCR on pathological change of kidneytissue of DM animal model.We establish rabbit DM model by using vein injection of alloxan. It is divided into DVgroup, DM group and C group. We select type â…£ collagen as a norm for ECM of DN. Atthe same time we observe the change of matrix metalloproteinase 9(MMP-9). We alsonotice that the attention is being paid to the function of integrins in renal disease. But thereis few report on it at home. The report on DN is even few. The attention has been greatlypaid to the change of the quantity of glomerulus ECM, abnormal regulation and itscomponent which play a important role in mesangial proliferation. As the receptor of ECM,the change of integrins may play an important role in the development of DN. Some ECMcan regulate the expression of MMPs, and it is found that the regulation is mediated byintegrin. We can guess that in the development of DN, the pathological change of ECM canlead to the change of matrix component and interaction of corresponding receptor moleculeof integrin, and the change of the expression of MMPs, which will have an effect on themetabolism of ECM. We can understand more deeply the mechanism of development in DNand the mechanism of therapy of VCR by observing the change of integrins and MMP₉ inthe model of DN treated by VCR.The results of the research are the following:1.The blood glucose of rabbit kept on rising after it got vein injection of alloxan.Insulin controlled blood glucose 16.7---28.0mmol/L. The mould of DM got shaped. After12 weeks, the kidney weight/body weight of VCR group is higher than that of C group, butlower than that of DM group(p<0.05). The urinary albumin of DM group is obviouslyhigher than that of C group. The urinary albumin of VCR group is evidently lower than thatof DM group.(p<0.05).2.Some glomerulus volume of DM group under the light microscope became larger.There was proliferation in mesangial cells and increased mesangial matrix. There was alsosegmental sclerosis. The glomerular basement membrane(GBM) became thicker. The closeof capillary cavity could be seen. Areas of glomerulus capillary, glomerulus mesangium andGBM in of DM group are apparently larger than that of C group.(p<0.05).The proliferationof mesangial cells of glomerulus in VCR group and the increase of mesangial matrixbecame less than that of DM group. GBM became a little thicker. All the areas of capillaryin glomerulus, glomerulus mesangial and GBM are obviously smaller than that of DMgroup.3.The immunohistochemistry(IH) showed that the normal glomerular integrinαv wasexpressed mainly on GBM. A small part was expressed on mesangium and bowmancapsule.The integrinαv was strongly expressed on mesangial district and GBM in DMgroup. The integrin αv in VCR group was expressed less strong. The quantity analysis ofthe IH indicated that the difference of all the norms among the three groups was significant.(p<0.05) .Western blot showed that the expression of integrinαv protein in DM group was3.1 times of that in C group. But compared with DM group, the expression of integrin αvprotein in VCR group decreased by 22.6%.4.The IH indicated that the normal glomerulus â…£_C was expressed on GBM,mesangium and bowman capsule. â…£ _C in DM group was strongly expressed onmesangium and GBM.The expression of â…£_C in VCR group was obviously weak. Thequantity analysis of the IH indicated the positive area of â…£_C in DM group was evidentlyhigher than that of corresponding part in C group. Compared with DM group, the positivearea of â…£_C in VCR group reduced obviously. (p<0.05) Western blot showed that theexpression of â…£_C in DM group was 2.8 times of that in C group. But compared with DMgroup, the expression of â…£_C in VCR group decreased by 28.6%.5.The IH showed that the normal glomerular MMP₉ was expressed on GBM,mesangium and bowman capsule. The expression of MMP₉ in glomerulus in DM groupobviously became weak. Compared with DM group, the expression of MMP₉ in VCRgroup was apparently stronger. The quantity analysis of the IH showed the positive area ofMMP₉ in DM group evidently decreased greatly. Compared with DM group, the positivearea of MMP₉ in treatment group increased obviously. (p<0.05= Western blot showedthat compared with C group, the expression of MMP₉ in DM group decreased by 59%. Butcompared with DM group, the expression of integrinαv in VCR group increased by 92.5%.The research brings forth new ideas in medical science. It is the first time to observethe pathology change of kidney tissue of rabbit DM model induced by alloxan and establishrelatively typical rabbit DN model. It is also the first time to make research on the impact ofVCR on the kidney pathological change of rabbit DM model. Cell adhesion moleculeintegrinαv and type â…£collagen which is the representative of collagen metabolism andMMP₉ changed greatly in kidney tissue of diabetic rabbit. VCR can reverse the changes,which provides theoretical foundation for its therapy of DN.