We have performed approximately 1200 cases of renal transplantation in mice with a technical success rate of >90%. Compared to heart transplantation, the success rate of kidney transplantation is usually low. However, our laboratory has maintained a high success rate (> 90%) of kidney transplantation. The key points for success are to reduce reperfusion injuries to both donor kidney and recipients, and minimize bleeding and thrombosis throughout the procedure and post-operatively. The following factors may be most important: (a) reduce bleeding in the recipient during surgery as much as possible through careful and gentle operation; (b) minimize warm ischemic and cross-clamping times during donor kidney preparation and recipient transplantation; (c) use a small donor bladder patch to prevent necrosis, insufficient blood supply and bladder leakage post-operation; (d) delay nephrectomy of the native kidney until 4 ~ 7 days post-transplantation to allow the transplanted kidney to recover function following surgery; (e) perform anastomoses (between the donor aortic cuff and the anterior wall and between the donor aortic cuff and the posterior wall of the recipient’s aorta) outside of the aorta to reduce the incidence of thrombosis; (f) keep recipient mice warm for at least for 24 hours following surgery; (g) give antibiotics to recipient mice post-operatively to prevent potential infections.
In this protocol, we use 10-0 instead of 11-0 suture without affecting survival rate. Although the 11-0 suture is ideal and used in many transplantation laboratories, we feel that 10-0 suture is sufficient for use in kidney transplantation as long as the factors described above are well controlled.
The removal of the remaining native kidney is essential so that decline in kidney graft function can be monitored by serum creatinine measurements. All kidney graft recipients undergo nephrectomy of the left native kidney between 4 and 7 days post kidney transplantation. Nephrectomy is not performed at the time of kidney transplantation because recipients characteristically suffer ill health or do not survive when both procedures are conducted at the same time. A 4 to 7 day lag between procedures permits the kidney graft to recover from ischemia and reperfusion injury before the native kidney is removed. Kidney graft function is assessed by daily examinations of overall animal health and blood creatinine levels. For reference, a non-transplanted, normal mouse has a creatinine level of about 20 micromol/L. Renal allograft rejection is suspected when the recipient mouse shows signs of illness and the creatinine level are elevated near 100 micromol/L at which time grafts are harvested for histopathological analyses.