Kidney tissues were fixed in 10% buffered formalin solution for 30 min at room temperature and dehydrated in 75% ethanol overnight, followed by paraffin embedding. Serial sections (4 µm, n=3/group randomly selected) were stained with hematoxylin for 15 min and eosin for 5 min at temperature to assess pathological changes using a BX40 upright light microscope (Olympus Corporation). Kidney damage scores were determined according to the extent of kidney injury, as previously described (13 (link),14 (link)), by two blinded researchers. Scoring was primarily based on the presence or absence of hemorrhaging, tubular cell necrosis, tubular dilatation and cytoplasmic vacuole formation. The grading system was scored as follows: 0, 0% damage (normal kidney); 1, 0-5% damage (minimal damage); 2, 5-25% damage (mild damage); 3, 25-75% damage (moderate damage); and 4, 75-100% damage (severe damage).