Kinetics of mouse renal allograft rejection, function, cell death, and lipocalin 2 (Lcn2) expression. Kidneys from Balb/c mice were transplanted into C57Bl/6 (Bl/6) mice. Allografts were harvested at posttransplant day 3, 5, or 7, stained with hematoxylin and eosin or periodic acid–Schiff stain and analyzed for histopathology by using Banff criteria. (A) Representative hematoxylin and eosin–stained images of control kidneys from sham‐operated mice (a) and allografts harvested at day 3 (b), day 5 (c), and day 7 (d) are shown. (B) The cumulative Banff score of histological lesions of the allografts harvested at given times is presented by a box plot. Function of the renal allografts was assessed by measurement of serum creatinine (C), serum urea (D), and serum Lcn2 (E) levels. Total kidney lysates of three animals in each of the indicated groups were used to determine activation (cleavage) of caspase 3 by immunoblotting. Representative immunoblot (F) and box plot (G) are shown. Lcn2 mRNA and protein expressions were investigated by quantitative polymerase chain reaction (H) and by immunohistochemistry (I), respectively, in the kidneys of sham‐operated mice (a) and allografts harvested at day 3 (b), day 5 (c), and day 7 (d). n = 6 (allografts harvested at day 3 or 5), n = 8 (allografts harvested at day 7). Scale bars = 100 μm. *p < 0.05, **p < 0.01.