In addition, HO-1 expression was down-regulated in AKI and CO + AKI groups compared with control group (p < 0.05); intense HO-1 staining was observed in the renal tubular epithelial cell cytoplasm in CUR + AKI group, levels were higher than that of the AKI and CO + AKI groups (p < 0.01). Here, HMOX1 is linked to acute kidney injury.