Fig. 6: Luminal granular cast accumulation and proliferation in uninjured PT-S2 segments after selective focal PT-S1 injury.
From: Longitudinal tracking of acute kidney injury reveals injury propagation along the nephron
Serial in vivo 2-photon microscopy images of representative CycB1-GFP kidney regions without (a) and with selective focal PT-S1 injury (b, c) through targeted 2-photon laser exposure (orange line). b Representative image series before and after laser-induced focal PT-S1 injury in which no granular cast accumulation was detectable in surrounding PT-S2 segments. Note local proliferation (arrowheads) in targeted PT-S1 segment with lacking unspecific epithelial injury or proliferation in surrounding tubule segments. c Representative image series before and after laser-induced focal PT-S1 injury in which luminal granular cast accumulation (arrows) and subsequent GFP expression (arrowheads) was detectable in surrounding, initially uninjured PT-S2 segments of remote distance to the injury site. Scale bar: 50 μm. d Volumetric quantification of GFP+ nuclei (% of total nuclei/segment) in non-granular cast-accumulating (uncasted) and granular cast-accumulating (casted) PT-S2 segments at day 02 after focal PT-S1 injury (n = 461 and 39 for uncasted and casted segments, from 7 mice); boxplot, line at median, edges at 25th and 75th percentiles, whiskers from min to max, points considered outliers. Statistical test: linear mixed-effect model, p-values from two-sided test (Supplementary Extended Statistics.u). e Linear regression of luminal granular cast area (% of total segment cross-sectional area) at day 01 and GFP+ nuclei (% of total nuclei/segment) measured 24 h later in uninjured PT-S2 segments (n = 498 from 7 mice). Fit (slope*x + intercept, plotted with 95% CI); R2, and Pearson’s coefficient (r) are reported. #: significant difference of slope and intercept from zero. f Normalized number of GFP+ nuclei detected in different area zones defined by increasing distance from the basolateral membrane of the laser-injured PT-S1 segment indicates no unspecific laser-induced proliferation in injury-adjacent tubules (0–35 µm). (n = 20 for each area zone from 7 mice); boxplot, line at median, edges at 25th and 75th percentiles, whiskers from min to max, individual points considered outliers). Statistical test: linear mixed-effect model, p-values from two-sided test (Supplementary Extended Statistics.u). */#: p < 0.05; **/##: p < 0.01; ***/###: p < 0.001.
