Reduced α-SMA induction occurs at day 7, but not day 3, after UUO in mice lacking tPA. (a) Western blot shows α-SMA expression in the obstructed kidney at day 7 after ureteral obstruction in tPA^+/+ and tPA^–/– mice. The samples were reprobed with actin to confirm equal loading of each lane. Lanes 1–5 represent individual animals in each group. (b) Graphic presentation of relative α-SMA abundance normalized to actin in tPA^+/+ and tPA^–/– mice. **P < 0.05, n = 5. (c) Representative Western blot shows the time course of α-SMA expression in the obstructed kidneys in tPA^+/+ and tPA^–/– mice. Sham-operated and obstructed kidneys were collected at 3 days and 7 days after surgery. The kidney homogenates were probed with antibodies against α-SMA and actin, respectively. (d) Graphic presentation of relative α-SMA abundance (fold induction with levels in sham kidney as 1.0) normalized to actin in tPA^+/+ and tPA^–/– mice at different timepoints (n = 5). *P < 0.01, tPA^+/+ vs. tPA^–/– mice at day 7 after UUO; ^†P < 0.05, day 7 vs. day 3 after UUO in tPA^–/– mice.