Using anti-IdU Ab (that recognizes IdU, but not CldU) and anti-CldU Ab (that recognizes CldU, but not IdU), two LRC populations (LRC-IdU and LRC-CldU) were identified and the numbers of them were analyzed. Results: Long labeling experiment demonstrated
that the number of BrdU-positive tubular cells was positively associated with labeling period. Majority of proximal tubular cells in the outer medulla of the kidney became BrdU-positive after 4-week labeling. Double labeling experiment showed that LRC-IdU and LRC-CldU were scattered in renal tubules, but were not co-localized. The numbers of each LRC was similar and significantly increased after injury. There was no significant difference in the ratio of cell division among these LRCs after ischemia. Conclusion: These findings suggest AZD1152 HQPA that the majority of proximal tubular cells in the outer medulla are slow-cycling and equally contribute to tubular recovery after renal injury. TSUJI KENJI, KITAMURA SHINJI, INOUE AKIKO, MAKINO HIROFUMI Department of Medicine
and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Introduction: Adult kidney stem/progenitor cells have been reported to make important roles in renal regeneration. We established an adult kidney stem/progenitor-like cell line (KS cells) from adult rat kidneys (Kitamura S et al., FASEB J, 2005) and reported that implanted KS cells contributed
to regeneration after AKI by directly differentiating into renal cells (Kinomura M et al., Cell transplantation, 2008). Secreted NU7441 concentration factors from tissue stem cells were reported to promote regeneration in other organs. Here we examined the effect of secreted factors from KS cells (CS-KS) to elucidate whether there is indirect regenerative pathway through the protective factors from adult kidney stem/progenitor cells. Methods: Male Sprague-Dawley rats were subjected to kidney ischemia/reperfusion (I/R) L-gulonolactone oxidase injury (45 min clamping on unilateral renal artery after uninephrectomy) and divided into three groups; sham, I/R and CS-KS (Intraperitoneal CS-KS administration 3 hours after I/R) groups, evaluating renal function, tubulointerstitial injury, cell proliferation, apoptosis and inflammation. We also examined the effect of CS-KS in vitro. Results: CS-KS treatment significantly suppressed urinary N-acetyl-b-D-glucosaminidase (NAG) level (I/R v.s. CS-KS group; 4.43 ± 1.76 v.s. 1.36 ± 0.99 U/l, p < 0.01) as well as the amelioration of renal tubulointerstitial injury on hematoxylin-eosin stain analysis. CS-KS also diminished inflammation (I/R v.s. CS-KS group; F4/80(+) area: 4.5 ± 2.4 v.s. 1.6 ± 1.0 × 103 pixel/ × 40 field, p < 0.01), suppressed tubular cell apoptosis (I/R v.s. CS-KS group; TUNEL(+) cells: 46.4 ± 14.5 v.s. 25.3 ± 13.0 / HPF, p < 0.01) and promoted cell proliferation in both residual renal cells and immature cells (I/R v.s.