Kidney Allograft And Postoperative Monitoring Of Banna Miniature Pig Inbred Line

Xenotransplantation is recently a hot spot in basic research on organ transplantation,and on January 10,2022,the University of Maryland School of Medicine announced the world’s first successful implantation of a gene-edited pig heart to a living person,thus it is urgent need to breed of domestic gene-edited pigs is imminent to cope up with foreign counterparts.In addition,the organs of gene-edited pigs need to be verified by animal experiments before they are used in humans,but it is expensive to directly transplant pig kidneys into monkeys,and this study aims to explore the relevant experimental conditions for pig-monkey kidney transplantation,which will lay down a foundation for allogeneic kidney transplantation between Banna miniature pigs.In this study,the inbred line of Banna miniature pigs with genetic stability and sensitivity to the external environment was selected,and three cases of pig-to-pig allogeneic kidney transplantation were performed using this inbred line.Prior to transplantation,donor matching experiments were performed by crossmatching,complement-dependent lymphocytotoxicity assay(CDC),and mixed lymphocytotoxicity assay(MLR).The surgical methods were iliac fossa ectopic kidney transplantation and left kidney exchange transplantation,which included donor kidney acquisition,trimming,and implantation.In order to evaluate the physiological indicators of recipient pigs and the function of transplanted kidney,the following postoperative parameters:measurements of porcine routine blood test,C reactive protein(CRP),liver and kidney function tests and blood pressure,inflammatory factor,ultrasonic and biochemical examination,as well as transplanted kidney pathological examination were included.Six Banna miniature pigs were matched in the following experiments:1915N1(D),1916N1(R),1843N1(DR1),1841N2(DR2),1793N1(C1)and 2504S3(C2).Four Banna miniature-pigs were operated on:D(donor pig)and R(recipient pig),DR1 and DR2(mutual donor recipient).The matching results showed that the donor crossmatch test of 4 pigs was negative,and the CDC and MLR matching results of D and R matching had the highest degree of overlap.The operation was divided into two groups according to different transplanted kidney sites.The surgical group I:allogeneic renal iliac fossa organ transplantation;and the surgical Group II:Allogeneic left kidney organ exchange transplantation.The operation process of three pigs was smooth,and the cold ischemia time for D,DR1 and DR2 was 4.58,1.24,and6.39 hours,respectively.The time of heat ischemia for D,DR1 and DR2 was 1.08,2.09,and5 minutes,respectively and the operation time for D and R was 5.26 hours,and the exchange of kidney transplantation time for DR1 and DR2 was 8.53 hours.R and DR2 survived after surgery,and DR2 died at 14 days.Compared with preoperative operation,Platelet count(PLT)and plateletcrit(PCT)of the three recipient pigs at 7 days after routine blood increased significantly(P<0.05).The blood pressure results showed that the Na~+concentration of all three recipient pigs was significantly reduced(P<0.05)after 14 days of surgery,and electrolyte abnormalities needed to be corrected by fluid replacement.Liver and kidney function test showed that serum alkaline phosphatase(P<0.05)and urea(P<0.05)levels of DR1 and DR2 were elevated one day after surgery,suggesting damage of both organs.Fourteen days after surgery,serum IL-2 and IL-8 levels of R and DR1 were significantly elevated(P<0.05),while IL-2 levels of DR2 tend to rise but gradually recover 15-17 days after surgery.Doppler ultrasound after 26 days post operation showed that the echo of renal parenchymal was uniform,the blood flow of arteriovenous vessels was smooth without any abnormality in resistance index.DR1 manifested no echo response in the kidney contour of the blood flow at 17 days after surgery,and it was judged that the transplanted kidney had lost its function.After dissection and histological comparison,it was found that there were gangrene-like lesions in the tissue structure with mucus and rancid odor.HE staining results showed that DR1 transplanted kidney tissue cells had a blurred contour with lysis of nuclei.These findings of DR1 transplanted kidney histology and HE staining results,they lost function before removal.Through the above experiments,we explored the operation conditions,process and maintenance process of allogeneic kidney transplantation in Banna miniature pigs,laying down the foundation for subsequent xenotransplantation.The immune rejection among inbred pigs is small and stable,and this pig can provide a good platform for future immune research.