In recent years, a large number of animal experiments and clinicopathological studies of human glomerular diseases have revealed that the development and poor prognosis of glomerular diseases are not only related to the damage of the glomerulus itself, but also closely related to the severity of tubular and interstitial lesions. The expression of α2 smooth muscle actin (α2SMA), vimentin (Vim), keratin (CK), proliferating cell antigen (PCNA) and collagen type IV (Col IV) can be observed by immunohistochemical staining of renal biopsies and transmission electron microscopy. Grade +: normal interstitium with mild tubular degeneration and dilatation; Grade ++: interstitial fibrosis, tubular atrophy <20%, scattered inflammatory cell infiltration; Grade +++: interstitial fibrosis, tubular atrophy 30%, scattered and/or diffuse inflammatory cell infiltration; ++++: interstitial fibrosis, tubular atrophy >50%, scattered and/or diffuse inflammatory cell infiltration; Grade +++: interstitial fibrosis, tubular atrophy >50%, scattered and/or diffuse inflammatory cell infiltration; Grade +++: interstitial fibrosis, tubular atrophy 30%, scattered and/or diffuse inflammatory cell infiltration. diffuse inflammatory cell infiltration. Endogenous creatinine clearance (CCr) was measured and found to be negatively correlated with interstitial changes, but not with glomerular index. It is believed that the early glomerular filtration rate changes are more accurately estimated by the tubular interstitial injury index than by the glomerular injury index. There are also scores of 0, 1, 2 and 3 based on tubular degeneration and necrosis according to no, mild, moderate and severe involvement, respectively. The overall score is grade 0: 0 points: grade 1: 1 to 4 points; grade 2: 5 to 8 points; grade 3: 9 to 12 points. Those with high scores also have more severe tubular interstitial lesions.