2.7 Hematoxylin and eosin staining (HE)
Renal tissue portions were fixed overnight with 4% paraformaldehyde, embedded in paraffin, sectioned, stained with HE, and then observed under an optical microscope (Olympus, Japan). The degree of renal injury was evaluated in three random fields per sample by grading the renal tissue injury as follows: 0-10%, 0; 11-25%, 1; 26-50%, 2; 51-75%, 3; and 76-100%, 4. At least five renal regions on each slide were randomly selected.