| Background:Kidney transplantation is the most effective treatment for end-stage renal disease (ESRD) patients presently. It extends their short-term survival and improves their quality of life. However, the long-term outcomes of transplanted recipients are unsatisfactory and patients with failed transplants waiting for retransplantation are increasing. Several factors including injuries before transplant (such as brain death, ischemia) and injuries after transplant (such as allograft rejection, infection, reperfusion injury) can lead to allograft dysfunction. Among these factors, the acute renal rejection is one of the most important concerns, with an incidence of10%of the cases. What’s more, a study reported that acute renal rejection can affect15-50%of renal transplant patients. Therefore, time-course evaluation of acute renal rejection is crucial to the management of transplanted recipients. Although the approach to evaluate allograft function is monitored by serum creatinine level, and a biopsy of the transplanted kidney remains’gold standard’for diagnosis of acute rejection, these clinical manifestations are relatively latter events comparing with initial events identified by molecular perturbations. Therefore, the molecular biomarkers would serve as predictive parameters to monitor the progress of subclinical and clinical acute rejection.Although the biomarkers in blood and urine of acute renal rejection are increasing, none could be widely applied in clinical evaluation, suggesting that the novel biomarker(s) should be still to be discovered. Most biomarkers of acute rejection mainly concentrated in the cytotoxic T-cells effector proteins and related immune molecules, yet, the mechanisms of acute rejection are not very clear and remain to be elucidated. It has been reported that acute tubular injury might be related to the causes of acute rejection. In addition, oxidative stress injury and inflammation may also cause allograft prone to acute rejection. Thus, it is unlikely that single biomarker would fit all the needs in the course of the acute rejection. The biomarker patterns including more individual parameters may offer more accurate information to the prognosis of allograft function. Nevertheless, the data on biomarkers under these confounded conditions are limited.Therefore, in our study, the aim is to examine the Neutrophil gelatinase-associated lipocalin (NGAL), Kidney injury molecule-1(KIM-1), C-reactive protein (CRP), malondialdehyde (MDA), soluble leukocyte antigen-DR (sHLA-DR) and their role of early detection of rat renal acute allograft rejection.Experimental transplantation in a small animal such as the rat has considerable advantages over that in larger animals. Multiple controlled experiments can be carried out. The rat is relatively cheap, easy to handle and house, and the existence of inbred strains allows for either iso-or allo-transplantation. However, techniques of organ grafting in the rat require skills in microsurgery which take a considerable time to acquire. However, any kind of rat kidney transplantation model has not been standardized presently. Currently, the end-to-end anastomosis is adopted as recommended technique of renal vein anastomosis. As we know, the diameter of rat renal vein is so tiny and the venous walls so extremely thin-walled, vulnerable, collapsible and easily adherent that it is greatly difficult to learn the rat renal venous anastomosis for trainee. However, few studies were reported to shorten the learning curve of trainee learning rat kidney transplantation and to lessen intraoperative complications of renal venous anastomosis for trainee.For many years, our team has done researches on combined liver-kidney transplantation in rabbits and kidney transplantation in rats. This study mainly aims at recommending the modified renal venous anastomosis of rat kidney transplantation to substitute the current method for trainee, by combining end-to-end anastomosis with epidural catheter to serve as a stent for the rat kidney transplantation model.Objective:1、various rat kidney transplantation models have been introduced over the decades and the study on the models seems to have been lack of novelty and necessity. However, vascular anastomosis, especially renal vein, is still very difficult for trainees. The aim of this study was to provide the modified renal venous anastomosis of rat kidney transplantation to substitute the current method for trainee.2、To analyze the risk biomarkers of renal acute rejection, we examined the role of serum NGAL, KIM-1, CRP, MDA and sHLA-DR levels as well as NGAL protein expression of transplanted kidney in a rat model of acute kidney allograft rejection.Methods:1. SD and Wistar rats were used as donors and recipients, respectively. The left orthotopic transplantation was performed. Artery end-to-side continuous sutures, renal vein end-to-end anastomosis with continuous sutures and interrupted sutures, ureter and bladder with the bladder flap anastomosis.2. Male Wistar rats were used as donors and recipients, respectively. The left orthotopic transplantation was performed with modified technique of renal vein anastomosis, combined the end-to-end sutures with epidural catheter. Meanwhile, the survival rate, warm ischemia time, renal venous anastomosis time and complications were recorded to evaluate the merits of the modified technique compared with the current recommended technique of rat renal vein. Two trainees took part in the learning of the models in two methods for performing30operations, respectively.3. Orthotopic Brown-Norway (BN) to Lewis allograft and Lewis to Lewis isograft kidney transplants were performed as experimental and control group, respectively. Five recipient rats each were harvested on day3,5,7after kidney transplant in a parallel subgroup, at which points the levels of serum NGAL, KIM-1, CRP, MDA and sHLA-DR as well as serum creatinine values and histopathology of grafts were examined. In addition, NGAL protein expression levels in transplanted kidney were also measured.Results:1.45kidney transplant models were completed, with success rate86.7%. Donor renal warm ischemia time is30±2min.2. The difference of warm ischemia time and renal vein anastomosis time was significantly short and the survival rate was statistically high in equal number operations (P<0.01) by comparing with the current recommended method. The intraoperative complications and postoperative complications of renal venous anastomosis were also significantly decreased (P<0.01).3. Serum creatinine levels of allografts, but not isografts, were significantly increased on day5post-transplantation (P<0.05). However, the serum NGAL, KIM-1, CRP and MDA levels in the experimental group were significantly higher on day3compared with that in control group after kidney transplant (P<0.01), and highest on day7, especially the values of serum CRP, sharply increased from5.106±0.55mg/l on day5to34.382±0.947mg/l on day7. Also, the NGAL protein expression levels of transplanted kidney in experimental group were significantly different from that in control group on day3,5,7after operation (p<0.01). Yet, the serum sHLA-DR levels in both groups were not significantly changed after surgery (p>0.05). Conclusion:1. The establishment of the orthotopic renal transplantation model with less complication was simple and stable which had higher achievement ratio.2. The technique with epidural catheter can shorten the learning curve of trainee learning rat kidney transplantation. It may replace the current recommended technique of rat renal vein for trainee.3. The levels of serum NGAL, KIM-1, CRP and MDA were positively associated with the development of rat acute rejection and might be potential noninvasive biomarkers of impending acute allograft rejection after rat kidney transplant. In addition, the serum CRP level may play an important role in the severity of rat acute rejection. |
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