比较他克莫司和霉酚酸酯对大鼠慢性移植肾肾病的影响

Impact of tacrolimus vs mycophenolate mofetil on the expression of fractalkine and CX3CR1 in rats with chronic allograft nephropathy

目的比较他克莫司（FK506）和霉酚酸酯（MMF）对慢性移植肾肾病（CAN）大鼠移植肾组织中趋化因子FKN以及受体CX3CRl表达的影响。方法以SD大鼠为供者，Wistar大鼠为受者，肾移植后制作慢性移植肾肾病模型。实验分为4组，每组均有24只。假手术组：只游离左肾血管和结扎右肾；对照组：受者为CAN对照；FK506组：受者为CAN，使用FK5060．15mg·kg^-1·d^-1；MMF组：受者为CAN，使用MMF20mg·kg^-1·d^-1除假手术组外，每组受者术后均先使用环孢素A（CsA）10mg·kg^-1·d^-1×10 d以渡过肾移植急性排斥期，然后予相应干预措施。分别于术后4、8及12周时处死受者，每组各时点处死的受者均为8只。光镜下检测移植肾组织的病理改变；采用免疫组织化学染色和实时荧光定量聚合酶链反应（PCR）检测移植肾组织中FKN和CX3CRl蛋白及其mRNA的表达。结果对照组术后4周时移植肾间质小血管内膜开始增厚，肾小球开始出现硬化表现。8周时上述变化更为显著，12周时移植肾50％以上的肾小球出现硬化以及肾小管萎缩、间质明显纤维化等改变。FK506组出现CAN病理改变的时间较对照组早，且病变程度相对较重。MMF组出现明显CAN病理改变的时间较对照组晚，且病变程度相对较轻。FKN和CX3CRl主要表达于肾小管上皮细胞的胞膜和肾小管间质，部分见于间质血管，偶见于肾小球壁层细胞。术后各时点的移植肾标本中，对照组FKN和CX3CRl的mRNA和蛋白表达均高于假手术组；FK506组均高于对照组；而MMF组均低于对照组。结论FKN和CX3CRl在肾小管间质中的表达可能与CAN中肾小管损伤、间质纤维化等病理改变密切相关。MMF可能通过下调FKN和CX3CRl的表达对CAN的进展具有延缓作用；而FK506可能通过上调FKN和CX3CRl的表达来促进CAN病变的发展。

Objective To investigate the effects of tacrolimus （FK506） vs mycophenolate mofetil （MMF） on the expression of Fractalkine （FKN） and CX3CR1 in renal tissues of rats with chronic allograft nephropathy （CAN）. Methods The SD（Wistar rat accelerated kidney sclerosis model was made following the procedure of Kamada with little modification. The rats were divided into 4 groups （each group n = 8）. Group A （sham-operation group）： The left kidney vessels were dissociated and the right kidney pedicle deligated. In group B （control group）, the rats were the receptor with CAN. In group C, FK506 （0. 15 mg·kg^-1 ·d^-1 ） was given in the rats with CAN, and in group D, MMF （20 mg·kg^-l.d^-1） was given in the rats with CAN. To prevent an initial episode of acute rejection, all rats （excluded pseudo-operation group） were treated with CsA （10 mg·kg^-1 ·d^-1） for 10 days before treatment with corresponding immunosuppresants. The rats were executed at the 4th, 8th and 12th week postoperation. The immunohistochemistry and real-time fluorescence quantitative PCR were used to detect the localization and expression of FKN/CX3CR1 in the grafted kidney. Results Small endanglum in the renal interstitium became thickening at the 4th week postoperation and glomerulum sclero- sis could be seen in the control group, which was most predominant at 8th week. More than 50% glo merulum sclerosis, renal tubule atrophy and interstitium fibrosis could be seen at 12th week postoperation. Pathological features of CAN ocurred earlier in FK506 group than those in control group, but significantly later in MMF group than those in control group. Immunohistochemistry revealed that FKN and CX3CR1 were mainly expressed in tubulointerstitium and on the basolateral membrane of tubular epithelial cells. Postive staining could be seen in some interstitial Vessels and occasionally in the parietal wall cells of glomeruli. The expression of FKN/CX3CR1 in grafted kidneys at all time points postoperation was significantly higher in FKS06 group than that in control group, but significantly lower in MMF group than that in control group. Conelmions FKN/CX3CR1 may play an important role in the development of tubular injury and interstitial fibrosis in CAN. MMF can prevent or inhibit the progression of CAN probably by down-regulating the expression of FKN and CX3CR1. FK506 can cause CAN probably by up-regulating the expression of FKN and CX3CR1.