Iso-and Xeno-transplantation of kidney metanephroi preserved in histidine-tryptophan-ketoglutarate solution

Abstract

Objective To evaluate the preservation effect of histidine-tryptophan-ketoglutarate (HTK) solution compared to Uinversity of Wisconsin Solution (UW) solution on organogenesis and function of embryonic metanephroi using an isograft or athymus animal model. Methods Whole metanephroi anlages from Lewis rats on embryonic day 16 (E16) immediately preserved in HTK or UW solution for 24, 48, 72 and 96 h at 0-4 ℃, were implanted in omenta of Lewis (Lewis→Lewis) rats or BALB/c (Lewis→BALB/c) nude mice. In vitro, Levels of lactate dehydrogenase (LDH; cell necrosis) and adenosine 5’-triphosphate (ATP) reserve of intracellular energy were measured for preserved E16 metanephros primordia. in vivo, developed metanephros primordia were observed for histopathological and electronic microscopy (EM) examination, or measured for graft survival rate and for clearance rate of inulin. Results Though release rate of LDH was lower in HTK at (6.5±1.1)%, (8.6±0.9)%, (11.3±1.3)%, (12.5±0.8)%, than in UW solution, yet had no significantdifference (F=0.752, P>0.05) preserved for 24, 48, 72 and 96 h. The ATP reserve (%) was significantly higher after ischemia (t=-2.725, P 0.05) up to 48 h and then 96 h in HTK and UW solution. Pre-implantation, the size and extent of tissue differentiation of E16 metanephroi preserved in HTK solution for 3 days were not so distinguishable from the size and differentiation of same chronological age such as E19 metanephroi. Four weeks post-implantation, E16 metanephroi had formed mature nephrons and collecting ducts. Hematoxylin and eosin (HE) and EM examination showed they had normal cellular and ultra structure. E16 metanephroi iso-or xeno-grafted after preservation in HTK and UW solution for 3 days had no significantly different values of graft survival rate at 100.0%, 100.0%, 73.3%, 0% (χ2=1.553, P>0.05) and 100.0%, 100.0%, 80.0%, 0% (χ2=0.653, P>0.05), and for clearance rate of inulin [(32.10±5.09) μl/(min·g), t=-0.264, P>0.05] after 8 weeks post-implantation. Conclusion Iso-or xenografted E16 metanephroi undergo growth and differentiation and exhibit excretory function after preservation in HTK solution for 3 days. Isograft and xenotransplant of metanephros anlage may be used as an effective animal model for comparing preservation effect of graft organ solutions. Key words: Metanephros; Homologous transplantation; Xenotransplantation; Histidine-tryptophan-ketoglutarate solution; Organogenesis