2003 年 28 巻 2 号 p. 242-250
The bulk of renal transplants in Japan are cases of living related transplantation in adults. Nevertheless, for a variety of reasons, renal transplantation from pediatric donors has not been actively pursued and there has been virtually no fundamental investigation pertaining to pediatric renal transplants. In the present study, we investigated the characteristics of ischemia reperfusion injury to the immature kidney.
The animals used in experiments were female Sprague-Dawley rats weighing 250 g or 300 g, used as adult rats, and Sprague-Dawley rats 2 weeks old, used as neonate rats. First the right kidney was excised and then the left renal artery and vein were clamped for 1 or 2 hrs. Survival rates 24 and 48 hrs after reperfusion were measured, as were serum BUN, creatinine and TNF-α. Expression of TNF-α mRNA in kidney, small intestine, liver, lung and spleen were also measured. In the histological examination, DNA synthetic activity was investigated using hematoxylin-eosin staining and the bromodeoxyuridine (BrdU) labeling index.
24 hrs after 1-hr clamping, no significant difference in survival rate could be noted between the adult group and neonate group. On the other hand, 24 hrs after 2-hr clamping, a statistically significant difference was recognized between the two groups, with the survival rate at 78.6% for the adult group but only 16.7% for the neonate group. Whereas the survival rate 48 hrs after 2-hr clamping was 27.3% for the adult group, it was only 7% for the neonate group. The survival rate dropped sharply for both groups but no significant difference was recognized. Serum BUN and creatinine values increased in both groups but there was no significant difference. TNF-α in serum and tissue increased conspicuously only in the neonate group. In both groups, the BrdU labeling index increased more in rats undergoing ischemia reperfusion than in rats undergoing kidney excision alone.
The results indicate that in terms of survival rate and TNF-α, the neoate group as donor is somewhat inferior to the adult group. However, there are no differences between the two groups in serum BUN and creatinine. Because DNA synthetic activity is higher in the neonate group, it is believed that the group could serve amply as transplant donor if postoperative regeneration can be skillfully induced.