Excessive Oxidative Stress Contributes to Increased Acute ER Stress Kidney Injury in Aged Mice

Figure 1

Differences in kidney function and renal lesions between old and young mice after high dose of tunicamycin injury (0.8 μg/g BW, group). (a, b) Increased BUN and Scr levels in old mice after high dose of tunicamycin injection: serum samples were obtained from 18–22-month- or 3–6-month-old mice prior to and after 72 hours of high dose of tunicamycin injection. (c, d) Representative kidney sections from (c) young and (d) old mice without receiving tunicamycin seem normal. (e, g) Extensive tubular vacuolation was present in young mice at 72 hours of high dose tunicamycin injury (PAS, (e) 200x, and (g) 400x). The lesions were localized in proximal tubules (red arrow) while the descending tubules extended from the injured proximal tubule were relatively normal as indicated by a (e) black arrow. (g) Nuclear pyknosis (condensation) and fragmentation were widely present (arrows). (f) Large vacuoles were less common in the kidneys of tunicamycin-treated old mice (200x). (f) However, the cellular damage was more severe with detachment of the whole segment of proximal tubular cells from the basement membrane in old mice (arrows). (h) Higher power magnification (400x) showed that cells in the injured tubules in aging kidney contained many small or fine vacuoles. Nuclear damages were also prominent. (i) Morphometry analysis revealed that tubular damage occurred nearly in all proximal tubules in old mice after high dose of tunicamycin injection. More apoptotic cell death in aging kidney after high dose of tunicamycin injury: apoptotic TUNEL staining was performed in kidney sections obtained from (l) young or (m) old mice at 72 hours of high-dose tunicamycin injection. Kidneys without tunicamycin treatment for (j) young and (k) old mice were as controls (400x). Nuclei with brown or black staining (DAB) were apoptotic cells (arrows). (n) More apoptotic cell counts in the kidneys from tunicamycin-treated old mice. vs. young mice. vs. the levels before tunicamycin injection. Data was expressed as . Scale .

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