Effect of honokiol on unilateral ureteral obstruction (UUO)-induced renal tubular injury and fibrosis. Representative sections of kidneys from sham- and UUO-operated mice treated with vehicle (Veh) or honokiol (HKL) were stained with (A) Periodic acid-Schiff stain (PAS) and (B) Masson’s trichrome (MTC). Scale bar = 100 μm. The bar graph shows semi-quantitative scoring of tubular injury by PAS, area fractions (%) of tubulointerstitial fibrosis, and degree of interstitial collagen deposition stained by MTC in the sham and UUO-operated kidneys. Ten randomly chosen, non-overlapping fields were quantified (n = 10 per group). Data are expressed as mean ± SD. *** p < 0.001 versus Veh or HKL; ### p < 0.001 versus UUO treatment with Veh; Sham, sham-operated mice; UUO, unilateral ureteral obstruction; Veh, vehicle; HKL, honokiol.