Abstract:Objective To explore the expressions of ubiquitin-specific protease 7 (USP7) and autophagy-related proteins in renal tissues and their associations with renal interstitial fibrosis(RIF) in the patients with chronic kidney disease (CKD). Methods A total of 55 CKD patients admitted to Shaanxi Provincial Peoples Hospital and underwent renal puncture biopsy from June 2021 to January 2022 were selected retrospectively. Immunohistochemical method was used to detect the expression levels of USP7 and autophagy-related proteins ［P62, microtubule-associated protein 1 light chain 3B(LC3B)］, RIF marker proteins ［α-smooth muscle actin (α-SMA), fibronectin (FN)］ in renal biopsy tissues of patients. The differences in USP7 expression in kidney tissues with different degrees of RIF were compared, and its correlation with laboratory related indexes (α-SMA, FN, P62 and LC3B) was analyzed. Results According to the order of non-fibrosis group, mild fibrosis group and moderate to severe fibrosis group, the expression levels of USP7 and autophagy-associated protein P62 increased gradually, while LC3B decreased gradually in renal tissue of CKD patients(P<0.01). In terms of clinical indexes, the USP7 expression level was positively correlated with blood urea nitrogen, creatinine, cystatin C (CysC), uric acid and neutrophil gelatinase-associated lipocalin (NGAL)（P＜0.01）, while negatively correlated with glomerular filtration rate（P＜0.05）. In terms of RIF marker protein and autophagy-related protein, the USP7 expression level was positively correlated with α-SMA, FN and P62 (r=0.928, P<0.01; r=0.871, P<0.01; r=0.770, P<0.01), while negatively correlated with LC3B (r=-0.668, P<0.01). Conclusion USP7 and cellular autophagy may be important factors in the occurrence and development of RIF in CKD, and USP7 may promote the occurrence of RIF by inhibiting cellular autophagy.