Kidney histology
Kidney samples were dehydrated with 10% phosphate buffered formalin followed by paraffin-embedding. Tissue sections of 4 μm were stained with periodic acid-Schiff (PAS) and Masson trichrome stain for morphology and fibrosis assessment, respectively. These sections were viewed using light microscopy and were semi-quantitatively estimated for renal tubular damage according to following scoring system: 0 for 0%, 0.5 for <10%, 1 for 10–25%, 2 for 26–50%, 3 for 51–75% and 4 for 76–100%. Severity of renal interstitial fibrosis was estimated according to the following four grades: 0% fibrosis (grade 0); 1-25% fibrosis (grade 1); 26-50% fibrosis (grade 2); and >50% fibrosis (grade 3) in interstitial area(Sethi et al., 2017).