Aggravation of macrophage-mediated inflammatory damage by knockdown of Nrf2 in a unilateral ureteral obstruction renal fibrosis model
WU Cunzao1, LU Hong2, ZHU Hengyue2, WENG Min1, SHI Chenghao1, LIN Zhouhao1, BAI Yongheng3
1.Department of Urology, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, China; 2.Department of Laboratory Medicine, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, China; 3.Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, China
WU Cunzao,LU Hong,ZHU Hengyue, et al. Aggravation of macrophage-mediated inflammatory damage by knockdown of Nrf2 in a unilateral ureteral obstruction renal fibrosis model[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2021, 51(6): 437-443.
Abstract：Objective: To study the mechanism of Nrf2 gene knockout and its effect on inflammatory injury in unilateral ureteral obstruction (UUO) renal fibrosis model. Methods: The experimental mice were randomly divided into four groups, namely Nrf2 wild-type UUO group (Nrf2Wild-type UUO), Nrf2 knockout UUO group (Nrf2KO UUO), Nrf2 wild-type sham operation group ( Nrf2Wild-type Sham) and Nrf2 gene knockout sham operation group (Nrf2KO Sham), with 6 animals in each group. PAS and Masson staining was used to detect tissue damage and total collagen accumulation; immunohistochemical staining was used to detect the expression of macrophage marker CD68 and IRF5; ELISA was used to detect the level of iNOS; qRT-PCR was used to detect the mRNA expression of pro-inflammatory genes IL-1β, IL-6 and TNF-α. The protein expression of IRF5 was determined by Western blot. Results: PAS staining showed that Nrf2 gene knockout did not cause renal tissue damage, but after the UUO model was constructed, the renal tissue damage significantly increased. The results of Masson and immunochemical staining showed that Nrf2 gene knockout aggravated the degree of interstitial fibrosis in the UUO model, and promoted the infiltration of CD68-positive macrophages, accompanied with the enhancement of iNOS level. Further study found that compared with Nrf2Wild-type UUO group, the mRNA expression levels of IL-1β, IL-6, and TNF-α in the kidney tissues in the Nrf2KO UUO group were significantly increased (P<0.05). At the same time, Western blot and immunochemical staining results showed that Nrf2 gene knockout increased the expression of IRF5 protein (P<0.05). Conclusion: Nrf2 gene knockout aggravates the inflammatory damage in the UUO renal fibrosis model, and its mechanism may be related to the promotion of IRF5-mediated infiltration of inflammatory macrophages, thereby increasing the synthesis and release of inflammatory factors.
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