Effect of FTY720 in rat small bowel transplantation: apoptosis of crypt cells and lymphocytes in gut-associated lymphoid tissues

AIM: We investigated the extent of apoptosis in crypt cells and Peyer's patches (PPs) during small bowel allograft rejection in rats to examine the effect of FTY720 during rejection. METHODS: Orthotopic small bowel transplantations (SBTs) were performed from BN to LEW rats. Isografted animals served as controls. Three groups of SBT animals were studied on days 3, 5, and 7 after operation: isograft, untreated allograft, allograft with FTY720. FTY720 was orally administered by gavage (1 mg/kg/d) to allograft recipients on 7 consecutive days. Cryostat sections were prepared from grafts, including PPs. An in situ end-labeling (ISEL) technique was used to detect apoptotic cells. Indirect immunoperoxidase staining was also performed using monoclonal antibodies against rat Fas/Fas-L. RESULTS: Graft survival was prolonged in the FTY720-treated group. The number of ISEL-positive enterocytes in the allografts increased significantly on days 3, 5, and 7 compared with the isograft group. In the FTY720-treated group, the number of ISEL-positive enterocytes in the allografts was down-regulated significantly on days 3, 5, and 7 compared with untreated allograft group. In the PPs, the number of ISEL-positive mononuclear cells increased significantly in the allografts compared with the isograft group. In the FTY720-treated groups, the number of ISEL-positive mononuclear cells were down-regulated significantly in the allografts compared with the untreated allograft group. The number of Fas/FasL-positive enterocytes were increased significantly in allografts compared with isograft group. In FTY720-treated groups, the number of Fas/FasL-positive enterocytes were down-regulated significantly on day 7 compared with the untreated allograft group. In the PPs, Fas/FasL-positive mononuclear cells also increased significantly on day 7 in the allografts compared with isografts. In the FTY720-treated groups, Fas/FasL-positive mononuclear cells were down-regulated significantly in the allografts compared with the untreated allograft group. CONCLUSIONS: The number of apoptotic enterocytes, lymphocytes, and Fas/FasL-positive lymphocytes increased during small bowel graft rejection. FTY720 prevented up-regulation of the number of apoptotic enterocytes, lymphocytes, and Fas/FasL-positive lymphocytes while also prolonging small bowel allograft survival.     

Apoptosis in kidney and pancreas allograft biopsies

BACKGROUND: Apoptosis is a particular form of cell death involved in the elimination of somatic cells. In this study, the occurrence of apoptotic cells in kidney and pancreas allograft biopsies was analyzed and correlated with the number of infiltrating macrophages and lymphocytes and granzyme B expression. METHODS: Kidney and pancreas biopsies from patients submitted to simultaneous pancreas-kidney transplantation were classified into three groups: acute rejection, chronic rejection, and transplant cases without evidence of rejection. Formalin-fixed paraffin biopsies were used to identify apoptosis by the terminal deoxynucleotidyl transferase [TdT]-mediated dUTP nick end labeling (TUNEL) method. RESULTS: In normal kidney, only few apoptotic cells were observed. In contrast, in kidney-allograft biopsies, the TUNEL signal was detected in the nuclei of tubular epithelial cells and also in mononuclear cells scattered in the interstitium. In pancreas biopsies, numerous apoptotic cells were detected in acinar cells, in ducts, and occasionally in islets. The number of apoptotic cells in acute pancreas rejection was significantly higher compared with acute rejection of kidney grafts (50+/-14 vs. 21+/-4 cells/mm2; P<0.05). In kidney biopsies, there was a positive correlation between apoptosis and macrophages (r=0.51; P<0.005), and apoptosis versus T lymphocytes (r=0.45; P<0.05). In pancreas biopsies, the number of apoptotic cells correlated only with the number of macrophages (r=0.41; P<0.05). CONCLUSIONS: Apoptosis occurs in kidney and pancreas allograft biopsies, markedly in acute rejection in pancreas biopsies. Although apoptosis may reflect a mechanism of down-regulation of the allograft immune response by eliminating infiltrating cells, the elimination of graft cells may result in graft damage, particularly in pancreas transplantation.     

氨基胍与环孢素A联用对大鼠心脏移植后急性排斥反应的影响

目的：探讨氨基胍与环孢素A联用对同种大鼠心脏移植后急性排斥反应的影响。方法：受体SD大鼠心脏移植后分为4组：（1）对照组：术后不作任何处理;（2）低剂量环孢素A（CsA)组;术后0－7d肌肉注射CsA2mg.kg^-1.d^-1;（3）氨基胍（AG）组：术后0－7d皮下注射AG600mg.kg^-1.d^-1;（4）低剂量CsA加AG组;术后0－7d肌肉注射CsA2mg.kg^-1.d^-1及皮下注射AG600mg.kg^-1.d^-1。术后4d测定急性排斥反应时移植心的诱生型一氧化氮合酶（iNOS)的表达及血清一氧化氮（NO）含量,并观察移植心存活时间。结果与低剂量环孢素A组相比较,低剂量环孢素A与氨基胍联用组不仅显著地抑制移植心iNOS表达与NO产生（P＜0．05）;而且显著地减轻急性排斥反应（P＜0．01）,延长了移植心存活时间（P＜0．05）。结论低剂量环孢素A与氨基胍联用,协同抑制急性排斥反应时移植心iNOS活性及NO产生;显著地延长移植物存活时间。     

大鼠移植心脏的细胞凋亡及其与急性排斥反应的关系

目的 观察移植心脏的细胞凋亡现象及其与急性排斥反应的关系。方法 建立大鼠异位心脏移植模型,用ＨＥ梁色和原位末端标记（ＴＵＮＥＬ）技术检测移植心脏切片,进行排斥反应的病理分级,计算凋亡指数（ＡＩ）。结果 发生凋亡的细胞主要是心肌细胞,在各级排斥反应中均可见凋亡细胞存在,且ＡＩ与急性排斥发生的分级成正相关;各级的ＡＩ与０级（无排斥反应）比较,差异均有显著性。结论 细胞凋亡与移植心脏急性排斥反应的严重程     

Cyclosporine treatment preserves coronary resistance artery function in rat cardiac allografts.

BACKGROUND: A marked decline in vascular myogenic response occurs during the course of rat cardiac allograft rejection. Two important contributory features are an inducible nitrous oxide synthase (iNOS)-catalyzed, NO-mediated vasodilation and a loss of smooth muscle function. In this study, we examine the effect of cyclosporine immunosuppressive therapy on the alleviation of arterial dysfunction of coronary resistance arteries in allografts using pressure myography. METHODS: Rats receiving heterotopic abdominal cardiac transplantation were treated with cyclosporine (5 mg/kg), Cremophore or distilled water. Coronary septal arteries (internal diameter 200 microm) were dissected from isograft (Lewis to Lewis) and allograft (Fisher to Lewis) rat hearts at Day 21 post-transplantation and mounted on a pressure myograph. Pressure-induced vasoconstriction was measured before and after iNOS inhibition with aminoguanidine (AG; 100 micromol/liter). Both endothelium-based (ACh-induced) and endothelium-independent (sodium nitroprusside-induced) vasorelaxation were also recorded in each group. RESULTS: Pressure-induced myogenic contraction was reduced in allograft coronary arteries at Day 21 post-transplantation compared with matched isografts (p < 0.05). AG potentiated myogenic tone in allograft arteries, but had no effect on untreated Day 21 isograft vessels, indicating the presence of iNOS-based relaxation only in allograft vessels. Depolarization-induced vasoconstriction was lower in allograft compared with isograft arteries (p < 0.05). Cyclosporine therapy also improved depolarization-induced constriction in allograft vessels compared with untreated groups (p < 0.05). Furthermore, cyclosporine therapy preserved endothelium-based and endothelium-independent vasorelaxation in allograft arteries at Day 21 post-transplantation. CONCLUSIONS: Cyclosporine immunosuppressive therapy has a significant effect on the alleviation of early endothelial and smooth muscle dysfunction in coronary allograft arteries.     

Expression of nitric oxide and inducible nitric oxide synthase in acute renal allograft rejection in the rat

BACKGROUND: Recent studies have shown that nitric oxide (NO) synthases, particularly inducible nitric oxide synthase (i-NOS), are induced in acute rejection episodes following heart, liver, pancreas and kidney allotransplantation. Furthermore, tissue and cellular injury has been demonstrated to be mediated by peroxynitrite (ONOO-), a metabolite of NO as well as a potent oxidant. However, a detailed relationship between NO, i-NOS and graft injury in transplantation remains elusive. METHODS: The present study used the following models of renal transplantation in rats: allografts (n = 5, Brown-Norway to Lewis [LEW] rats), isografts (n = 5, LEW to LEW) and allografts treated with aminoguanidine (AG), an i-NOS inhibitor (n = 5). Blood urea nitrogen (BUN), serum creatinine (SCr) and urinary and serum nitrosocompounds (NOx) were measured on days 2, 4 and 7 post-transplant. Western blot analysis of i-NOS protein expression and measurement of i-NOS activity were carried out in grafts harvested on Day 7, along with immunohistochemical and histopathological examinations. RESULTS: In the allograft group, both BUN and SCr levels increased markedly on Day 7, in parallel with a sharp increase in NOx. A band stained by anti-i-NOS antibody was detected at approximately 130 kDa, along with high levels of i-NOS activity and diffusely distributed i-NOS-positive cells (macrophages). Histologically, an acute rejection episode was confirmed (Grade 3 according to Banff classifications). In the AG group, reduced renal function and graft injury were significantly less severe than in the allograft group. CONCLUSIONS: In rat renal allograft acute rejection, markedly increased levels of serum NOx were observed, along with enhanced tissue i-NOS activity, together resulting in graft injury. AG administration suppressed the increase of serum NOx levels, with concomitant mitigation of tissue injury and renal function impairment.     

Altered distribution of class I and class II MHC antigens during acute pancreas allograft rejection in the rat

The expression of MHC class I and class II antigens was investigated in a model of acute pancreas allograft rejection in the rat. Pancreaticoduodenal and duct-ligated DA(RT1a)-to-LEW(RT1(1] and LEW(RT1(1]-to-LEW.1U(RT1u) pancreas grafts were compared with normal organs and with LEW(RT1(1] isografts at daily intervals from day 1 to day 10 after transplantation. The results show profound changes of MHC antigen distribution in allografts during the process of rejection. Exocrine acinar cells, being class-I-antigen-negative in the normal pancreas, strongly express these antigens during rejection. Class II antigens, normally not found in pancreatic endothelia or parenchymal cells, appear in duct epithelia, acinar cells, and endothelia of big vessels. Endocrine islet cells and smooth muscle cells stay Ia-negative throughout the rejection process. Focal class I reactivity is also observed in acinar cells of pancreaticoduodenal isografts; but class II antigens are neither seen in parenchymal cells nor in endothelia of any isograft. Thus, in the rat pancreas allograft model, the induction of class II antigens is an early phenomenon characteristic of an ongoing immune response, and it provides a valuable new diagnostic criterion. Antibodies reactive exclusively with donor-haplotype antigens demonstrate an increase in donor-derived class I and class II antigen-positive interstitial cells in addition to parenchymal antigenic changes. A possible effect of the antigenic alteration described on the course of the rejection process is discussed.     

FK506 rescues peripheral nerve allografts in acute rejection

This study investigated the ability of the immunosuppressant FK506 to reverse nerve allograft rejection in progress. Eighty-four Buffalo rats received posterior tibial nerve grafts from either Lewis or Buffalo donor animals. Allografts were left untreated for either 7, 10, or 14 days before receiving daily subcutaneous FK506 injections (2 mg/kg). Time-matched control animals received either an isograft, an allograft with continuous FK506, or an allograft with no postoperative FK506 therapy. All animals underwent weekly evaluation of nerve function by walking track analysis. Experimental group animals were sacrificed either immediately prior to initiation of FK506 therapy (days 7, 10, or 14), after 2 weeks of immunosuppressive treatment, or 8 weeks postsurgery. Histomorphometric analysis, consisting of measurements of total number of nerve fibers, neural density, and percent of neural debris, demonstrated a statistically significant increase in regeneration in the isograft group relative to the untreated allograft group within 28 days of transplantation. Grafts harvested from animals receiving 2 weeks of FK506 after 7 or 10 days of rejection were histomorphometrically similar to time-matched isografts. By contrast, grafts from animals receiving 2 weeks of FK506 following 14 days without therapy resembled untreated allografts and demonstrated significant histomorphometric differences from isografts at the corresponding time point. Analysis of walking track data confirmed that relative to untreated allografts, functional recovery was hastened in animals receiving an isograft, or allograft treated with FK506. This study demonstrated that when started within 10 days of graft placement, FK506 could reverse nerve allograft rejection in rats evaluated following 2 weeks of treatment.     

小肠移植排斥反应期移植肠粘膜细胞凋亡的研究

目的 明确移植肠上皮细胞凋亡在小肠移植排斥反应中的意义及诊断价值。方法 选用近交系大鼠Ｆ３４４／Ｎ和Ｗｉｓｔａｒ／Ａ进行全小肠异位移植,实验分４组。第１组：非基本对照 ;第２组;同基因移植组;第３组;异基因移植组;第４组;异基因移植加环孢霉素Ａ治疗组。术的第３、５、７天取移植肠进行病理学检查,采用ＴｄＴ介导的脱氧核苷酸原位末端标记法（ＴＵＮＥＬ）检测移植肠上皮细胞凋亡。结果 病理学检查显示第３组大     

大鼠移植小肠急性排斥反应期组织病理学研究

目的　探讨大鼠异位小肠移植急性排斥反应期移植小肠病理学特点及意义。方法　实验分 4组 ,每组 6只。A组为非手术对照组 ;B组为异系移植组 ;C组为同系移植组 ;D组为异系移植加环孢霉素A治疗组。术后 3 ,5 ,7,10d取移植小肠进行病理学检查 ,测量黏膜厚度 ,绒毛高度和隐窝深度 ;并检测 3 ,5 ,7d移植小肠黏膜细胞凋亡。结果　A组小肠黏膜正常 ;B组移植小肠炎性细胞浸润、黏膜结构破坏程度和黏膜细胞凋亡数目明显高于C ,D组 ,随移植时间的延长黏膜细胞凋亡数目增加 ,黏膜结构破坏程度加重 ;C组移植小肠黏膜结构损伤程度较B组轻 ;D组仅有少量炎性细胞浸润 ,间质轻度水肿 ,未见黏膜结构破坏。结论　炎性细胞浸润、黏膜细胞凋亡和黏膜结构破坏是移植小肠急性排斥反应损伤病理学变化的主要特点。动态观察移植小肠病理学变化和细胞凋亡 ,对诊断小肠移植急性排斥反应和估计损伤程度有一定的价值。     

Trafficking of donor-derived bone marrow correlates with chimerism and extension of composite allograft survival across MHC barrier

We proposed to evaluate differences between recipient's immune response to vascularized skin and combined vascularized skin/bone allografts, under a 7-day alphabeta-TCR plus cyclosporine (CsA) treatment protocol. Thirty-six transplantations were performed in six groups: group I (isograft control-vascularized skin graft; n=6); group II (isograft control-combined vascularized skin/bone graft; n=6); group III (allograft rejection control group-vascularized skin graft; n=6); group IV (allograft rejection control-combined vascularized skin/bone graft; n=6); group V (allograft treatment-vascularized skin graft; n=6); and group VI (allograft treatment-combined vascularized skin/bone graft; n=6). Isograft transplantations were performed between Lewis rats and allografts were transplanted across the MHC barrier from Brown Norway to Lewis rats. In the allograft treatment group, a combined alphabeta-TCR+CsA protocol was applied for 7 days. All groups were compared clinically, immunologically and histologically. Statistical significance was determined with two-tailed Student's t test. Indefinite graft survival was achieved in the isograft control group (>300 days). Allograft rejection controls rejected within 5 to 9 days posttransplant; chimerism levels were undetectable (<.5%). Allografts under the alphabeta-TCR+CsA protocol had significantly extended survival when skin was combined with bone (61-125 days) compared to vascularized skin allografts (43-61 days). Lymphoid macrochimerism was significantly higher in group VI than group V. Histology confirmed skin and bone viability. Combined vascularized skin/bone allografts had higher and sustained levels of donor-specific chimerism and extended allograft survival.     

Effect of FTY720 and ex vivo graft irradiation in rat small bowel transplantation: apoptosis of crypt cells and lymphocytes

OBJECTIVE: We investigated the extent of apoptosis in crypt cells and Peyer's patches (PPs) during small bowel allograft rejection in rats to examine the effect of FTY720 and ex vivo graft irradiation during rejection. MATERIALS AND METHODS: Orthotopic small bowel transplantations (SBT) were performed from Brown Norway (BN) rats to Lewis (LEW) rats. Four groups of SBT animals were studied on days 3, 5, and 7 after operations: untreated allograft, allograft with FTY720, allograft with irradiation, and allograft with FTY720+irradiation. Cryostat sections were prepared from the grafts, including PPs. An in situ end-labeling (ISEL) technique was used to detect apoptotic cells. Indirect immunoperoxidase staining was also performed using monoclonal antibodies against rat Fas/FasL. RESULTS: The graft survival was prolonged in the FTY720-treated groups. In the FTY720-treated group, the number of ISEL-positive enterocytes was significantly down-regulated on days 3, 5, and 7 compared with the untreated allograft group. The number of ISEL-positive mononuclear cells was also significantly down-regulated compared with the untreated allograft group. The FTY720 the radiation and the FTY720+irradiation treated groups showed significantly down-regulated numbers of Fas/FasL-positive enterocytes on day 7 compared with the untreated allograft group. Fas/FasL-positive mononuclear cells were also significantly down-regulated in the allograft compared with the untreated allograft group. CONCLUSIONS: FTY720 and ex vivo graft irradiation prevented up-regulation of the number of apoptotic enterocytes, lymphocytes, and Fas/FasL-positive lymphocytes, and also prolonged small bowel allograft survival. Combination FTY720 and ex vivo graft irradiation did not affect graft survival and apoptotic cell expression compared with the FTY720 only group. These findings suggest that FTY720 may prevent both rejection-associated and sepsis-induced apoptosis during the late phase of small bowel graft rejection.     

Macrophage-derived interleukin-18 in experimental renal allograft rejection.

BACKGROUND: Interleukin 18 (IL-18) is primarily a macrophage-derived, pro-inflammatory cytokine. As macrophages can act as effector cells in acute rejection, we examined the role of IL-18 in a rat model of acute renal allograft rejection. METHODS: Life-sustaining orthotopic DA to Lewis allograft and Lewis-Lewis isograft kidney transplants were performed. In the same model, macrophage-depleted animals, achieved with liposomal-clodronate therapy, were also studied. Macrophage (ED1+) accumulation and IL-18 expression was assessed by immunohistochemistry. CD11b+ cells (macrophages) were isolated from kidney and spleen by micro beads. Real-time PCR was used to assess IL-18 and INF-gamma mRNA expression in tissue and cell isolates. RESULTS: Allografts, but not isografts, developed severe tubulo-interstitial damage and increased serum creatinine by day 5 (P<0.001). Immunohistochemistry revealed a greater ED1+ cell accumulation in day 5 allografts compared with isografts (P<0.001). IL-18 mRNA expression was increased 3-fold in allografts compared to isografts (P<0.001). Accordingly, IL-18 protein was increased in allografts (P<0.001), and was predominantly expressed by ED1+ macrophages. CD11b+ macrophages isolated from allografts had a 6-fold upregulation of IL-18 mRNA expression compared to isograft macrophages (P<0.001). Macrophage depletion resulted in a marked attenuation of allograft rejection, ED1+ and IL-18+ cells were significantly reduced (P<0.05) as was IL-18 mRNA expression (29.28+/-2.85 vs 62.48+/-3.05, P<0.001). INF-gamma mRNA expression (P<0.01) and iNOS (P<0.001) production were also significantly reduced in the macrophage-depleted animals. CONCLUSION: This study demonstrates that IL-18 is significantly increased during acute rejection and is principally produced by intra-graft macrophages. We hypothesize that IL-18 upregulation may be an important macrophage effector mechanism during the acute rejection process.     

Histologic diagnosis of rejection by using cystoscopically directed needle biopsy specimens from dysfunctional pancreatoduodenal allografts with exocrine drainage into the bladder

To determine the histologic features of rejection and to identify nonrejection causes of human pancreatic allograft dysfunction, we analyzed 31 needle biopsy specimens (17 pancreatic, 14 duodenal) obtained under cystoscopic direction from 15 dysfunctional pancreatoduodenal allografts with exocrine drainage into the bladder. Eight allografts undergoing rejection showed the most common histologic features of rejection to be diffuse mixed inflammatory infiltrates of pancreatic acinar tissue and duodenum wall. Diffuse infiltration of pancreatic acinar tissue by neutrophils was the earliest histologic change in rejection. Seven dysfunctional allografts not undergoing rejection ("nonrejection") showed a normal pancreas or various changes including acinar dilation with inspissation of secretions, fibrosis, cytomegalovirus inclusions, and enzymatic necrosis. The histologic changes in the duodenum paralleled those in the pancreas in both rejection and nonrejection allografts. We conclude that the histologic features of rejection in pancreatoduodenal allografts are distinctive. The changes seen in biopsy specimens accurately reflect the state of the graft and can be used to diagnose rejection and to identify other causes of graft dysfunction. Biopsy samples from the duodenum as well as the pancreas are diagnostically useful. The biopsy findings can be used to guide the clinical management of rejection and in the development of other noninvasive tests for rejection.     

Nitric oxide production by bronchoalveolar cells during allograft rejection in the rat.

BACKGROUNDS: We reported the increased nitric oxide (NO) level in exhaled air of rat lung transplant recipients during acute rejection (AR). The aim of this study was to determine the site and level of NO production in the rejected graft. METHODS: Rat lung transplantation was performed in isografts and allografts. RESULTS: In isografts, no AR and no significant increase in NO production was identified. In allografts, grades I-II of AR was seen on postoperative day (POD) 3 and grade III on POD 5. NO produced by BAL cells increased on both POD 3 (11.8+/-2.0 parts per billion [ppb]) and POD 5 (115.3+/-66.9 ppb). There was a highly significant correlation between the level of NO and the severity of AR (p=0.862, P<0.005). BAL cells from allografts expressed iNOS mRNA. Among them, macrophages, lymphocytes and neutrophils were immunostained for iNOS. CONCLUSION: NO produced by BAL cells was detected in the early stages of rejection. Therefore, it may serve as a sensitive indicator of AR in lung transplantation.     

黄嘌呤氧化脱氢酶在大鼠肾移植急性排斥反应中的作用

目的 观察黄嘌呤氧化脱氢酶(XOD)在大鼠肾移植急性排斥反应中的作用.方法 实验分同系移植组和异系移植组两组.采用左肾原位移植术建立大鼠.肾移植模型.分别于术后1、4、7 d切取受体左肾,观察其形态学改变,应用比色法检测移植肾组织中XOD和活性氧(ROS)的活力,应用免疫组织化学技术检测XOD的表达.结果 异系移植组术后第4、7天呈现典型的急性排斥反应的病理改变.该组各时间点的XOD活力、ROS水平、Banff总分及免疫组织化学评分与同系移植组比较,差异均有统计学意义(P＜0.05).异系移植组移植肾XOD活力、ROS水平、Banff总分及免疫组织化学评分之间均呈正相关(r≥0.751,P＜0.01).XOD表达于肾小管上皮细胞、肾小球内皮细胞和浸润的单核巨噬细胞中.结论 XOD与肾移植急性排斥反应的发生发展密切相关.     

急性排斥反应时Fractalkine及其受体在移植心脏中的表达

目的　探讨急性排斥反应过程中Fractalkine(FKN)及其受体CX3CR1在移植心脏局部表达的意义及环孢素A(CsA)对它们的影响。　方法　施行大鼠异位心脏移植术 ,移植大鼠分为 3组 ,每组 45只 ,对照组 5只。SD大鼠间的移植为同系移植组 (A组 ) ,Wistar至SD大鼠的移植分为未用CsA干预组 (B组 )及CsA干预组 (C组 ) ,健康SD大鼠为对照组。采用RT PCR方法检测排斥反应中移植心脏局部FKNmRNA的表达水平 ,免疫组化方法检测FKN和CX3CR1的蛋白表达水平。　结果FKNmRNA与蛋白在A组各时间点和对照组均呈低水平表达 ;在B组的表达变化与急性排斥反应的进程相关 ,术后第 7天FKNmRNA表达上调至峰值 (0 8± 0 2 6) ;C组应用CsA后 ,FKNmRNA表达峰值显著低于B组 (t=2 3 90 ,P <0 0 5 )。FKN和CX3CR1蛋白分别定位于移植心脏血管内皮细胞及间质浸润的单个核细胞中。　结论　急性排斥反应过程中 ,FKN及其受体CX3CR1表达上调 ,与移植物间质单个核细胞浸润密切相关 ;抑制FKN CX3CR1通路的活化可能是CsA发挥作用的又一分子免疫学机制