TGFB1 and renal fibrosis: An early acute phase from day 0 to day 5, which is characterized by acute PTEC necrosis accompanied by an increased expression of TGFβ, activation of p-Smad2/3 initially mainly in the areas of external part of medullary rays, and a chronic phase from day 6, which is mostly represented by interstitial cells infiltration leading progressively to marked tubular atrophy and renal fibrosis at day 35, as attested by alpha smooth muscle actin (αSMA) positive myofibroblasts and collagens deposition in the vicinity of damaged proximal tubules.