Fig. 4.

Effects of ErbB4 deletion on tubular injury after UUO. A: kidney injury molecule-1 (KIM-1) immunohistochemistry staining. In sham-operated kidneys, no KIM-1 immunostaining was detected in either group. Post-UUO injury (1 day), KIM-1 immunostaining was dramatically increased in the S3 segments and was also detected in S1 and S2 segments at 3 and 6 days post-UUO in both groups. Scale bar, 100 µm. B: quantification of KIM-1-positive immunostaining area of A using Image J software. Values represent means ± SE from 20 random fields of 4–6 kidneys in each group. C: expression levels of kidney injury marker proteins by immunoblotting. KIM-1 expression levels increased early in the UUO injury by 1 day post-UUO and remained elevated at days 3 and 6 post-UUO with no significant differences between wild-type and ErbB4^−/−ht⁺. Elevated heart fatty acid-binding protein (H-FABP) levels were detected 3 days post-UUO injury and remained elevated at 6 days post-UUO in ErbB4^−/−ht⁺ mouse kidneys compared with wild-type kidneys at the same time points. Baseline caspase-3 expression was detected in sham-operated kidneys. After UUO, kidneys from ErbB4^−/−ht⁺ mice showed slightly higher levels of total caspase-3 at 1 and 3 days post-UUO, whereas elevated cleaved caspase-3 was only detected at 6 days post-UUO. Images represent 3 independent experiments of 6 samples from each group.