Abstract:Objective: To explore the role of downregulating AlkB homolog 5 (ALKBH5) in rats with pulmonary fibrosis (PF) and its potential mechanism based on the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway. Methods: A rat model of PF was established by intratracheal instillation of bleomycin. Successfully modeled Sprague-Dawley (SD) rats were divided into the model group (PF + no drug treatment), si-NC group (PF + transfection with si-NC via tail vein injection), si-ALKBH5 group (PF + transfection with si-ALKBH5 via tail vein injection), and pathway activator group (PF + transfection with si-ALKBH5 + 30 mg/kg TGF-β1 pathway activator SRI-011381 via tail vein injection). Another 12 normal rats were selected as the control group. RT-qPCR was used to detect the mRNA levels of ALKBH5, inducible nitric oxide synthase (iNOS), cluster of differentiation 86 (CD86), arginase-1 (Arg-1), and mannose receptor (CD206) in lung tissues. A pulmonary function detector was used to measure tissue damping (G), respiratory system resistance (Rrs), respiratory system compliance (Crs), and tissue elastance (H) in rats of each group. Hematoxylin-Eosin (HE) staining and Masson staining were performed for histopathological analysis of the lungs. Western Blot was used to detect the expression levels of ALKBH5, type I collagen (Col I), fibronectin (FN), α-smooth muscle actin (α-SMA), and proteins related to the TGF-β1/Smad pathway. Results: Compared with the control group, the lung structure of rats in the model group was damaged, with thickened alveolar septa and necrosis of alveolar epithelial cells; the levels of G, Crs, Arg-1 mRNA, and CD206 mRNA were significantly decreased (P<0.05); while the levels of ALKBH5 mRNA and protein, Rrs, H, collagen fiber deposition, Col I, FN, α-SMA, iNOS mRNA, CD86 mRNA, TGF-β1, p-Smad2, and p-Smad3 were significantly increased (P<0.05). Compared with the model group and si-NC group, the alveolar septa in the si-ALKBH5 group and pathway activator group were slightly thickened, and the lung tissue structure was relatively intact; the levels of G, Crs, Arg-1 mRNA, and CD206 mRNA were significantly increased (P<0.05); while the levels of ALKBH5 mRNA and protein, Rrs, H, collagen fiber deposition, Col I, FN, α-SMA, iNOS mRNA, CD86 mRNA, TGF-β1, p-Smad2, and p-Smad3 were significantly decreased (P<0.05). Compared with the pathway activator group, the degree of lung tissue injury in the si-ALKBH5 group was improved; the levels of G, Crs, Arg-1 mRNA, and CD206 mRNA were significantly increased (P<0.05); while the levels of ALKBH5 mRNA and protein, Rrs, H, collagen fiber deposition, Col I, FN, α-SMA, iNOS mRNA, CD86 mRNA, TGF-β1, p-Smad2, and p-Smad3 were significantly decreased (P<0.05). Conclusion: Downregulating ALKBH5 can alleviate pathological damage and collagen deposition in lung tissue, reduce lung function impairment, inhibit PF in rats, and suppress the polarization of macrophages to the M2 type. The mechanism may be related to the inhibition of the TGF-β1/Smad signaling pathway.
岱德羽, 党慧, 王雪, 王春雨, 侯冬华. TGF-β1/Smad通路下调ALKBH5调控巨噬细胞极化改善大鼠肺纤维化的作用机制[J]. 河北医学, 2025, 31(10): 1625-1632.
DAI Deyu, DANG Hui, WANG Xue, et al. Mechanism of Downregulating ALKBH5 in Improving Pulmonary Fibrosis in Rats by Regulating Macrophage Polarization by TGF-β1/Smad Pathway. HeBei Med, 2025, 31(10): 1625-1632.