Properties of the isolated rabbit proximal convoluted tubule and pars recta after long-term storage in a modified Collins solution.

The effect of storage of cortical slices in modified Collins solution on the viability of rabbit proximal convoluted tubules (PCT) and pars recta (PR) was evaluated by microperfusion of isolated tubules in vitro. Cortical slices of rabbit kidney were stored for 1, 24, 48, 72 and 97 h at 4 degrees C in modified Collins solution. PCT and PR were dissected from these slices and perfused with a modified Krebs-Henseleit solution in vitro. Fluid absorption (JV) was 1.21 +/- 0.3 nl min-1 mm-1 (N = 8) and the transepithelial potential difference (PD) was -2.3 +/- 0.3 mV (N = 6) for PCT from cortical slices stored 0 to 3 h. JV was 1.01 +/- 0.09 nl min-1 mm-1 (N = 8) and PD was -1.9 +/- 0.6 mV (N = 5) for PCT from tissue stored 23 to 97 h. JV of PR from tissue stored 5 to 26 h was 0.75 +/- 0.1 nl min-1 mm-1 (N = 5) and PD was -1.5 +/- 0.3 mV (N = 5). JV was 0.76 +/- 0.1 nl min-1 mm-1 (N = 3) for PR stored 72 to 74 h, and PD was not measured. There was no correlation between storage time and JV or PD. Furthermore, the JV and PD values for these tubules were similar to those obtained for freshly dissected tubules. These results show that the isolated tubule preparation is useful for the direct assessment of the efficacy of different kidney preservation solutions on nephron function.