Improved cold preservation of kidney tubular cells by means of adding bioflavonoids to organ preservation solutions

Background. Cold ischemia and reperfusion during renal transplantation result in release of reactive oxygen species. The aim of this study is to examine whether cold storage induced cell injury can be ameliorated by adding flavonoids directly to preservation solutions. Methods. Cultured renal tubular epithelial cells (LLC-PK1) were stored in University of Wisconsin (UW) or Euro-Collins (EC) solution at 4 degrees C for 20 hours. Preservation solutions were supplemented with various flavonoids. After rewarming, structural and metabolic cell integrity was measured by lactate dehydrogenase (LDH) release and MTT-test, and lipid peroxidation was assessed from generation of thiobarbituric acid-reactive substances (TBARS). Results. Twenty hours of cold storage resulted in a substantial loss of cell viability in both preservation solutions (in EC: LDH release 92.4 +/- 2.7%; MTT-test 0.5 +/- 0.7%). Addition of luteolin, quercetin, kempferol, fisetin, myricetin, morin, catechin, and silibinin significantly reduced cell injury (for luteolin in EC: LDH release 2.4 +/- 1.6%; MTT-test 110.3 +/- 10.4%, P < 0.01; TBARS-production (related to cold stored control cells) 8.9 +/- 2.6%). No cytoprotection was found for apigenin, naringenin, and rutin. Protective potency of flavonoids depends on number of hydroxyl-substituents and lipophilicity of the diphenylpyran compounds. Conclusion. Cold storage induced injury of renal tubular cells was substantially ameliorated by adding selected flavonoids directly to preservation solutions.