Leflunomide Induces Dose-Dependent Lung Injury in Mice via Stimulating Vimentin and NLRP3 Inflammasome Production

Abstract

Recently, the therapeutic importance of the anti-rheumatic drug, leflunomide, has been increased after the involvement of leflunomide in treating other autoimmune diseases and its promising role in retarding human malignancies. Few studies have focused on the safety in human or animals without clear outlining of the pathologic features on target organs. One clinical study related leflunomide with significant pulmonary complications in predisposed individuals. The current study examined the dose-dependent lung injury produced by leflunomide in healthy mice. Albino mice were allocated into four different groups. Group (1): Vehicle control group, Group (2–4): mice received leflunomide (2.5, 5 or 10 mg/kg), respectively, for 8 weeks and then lungs were dissected from the mice for histopathological examination and fibrosis evaluation (Masson’s trichrome staining and α-smooth muscle actin immunohistochemistry). Enzyme linked immunosorbent assay was used to assess the vimentin and other inflammatory factors in the lung homogenate whereas Western blot analysis was employed to assess α-smooth muscle actin, vimentin and collagen 1. Results indicated that leflunomide induced dose-dependent pulmonary injury and the high dose and increased the vimentin, inflammatory markers (NLRP3 and interlukin-1β). Histologic examination showed distorted architecture, marked inflammatory cells infiltrate and increase collagen content. The findings were supported by Western blotting and the immunohistochemical study which showed greater pulmonary α-smooth muscle actin and vimentin content. In conclusion, the current results highlighted that leflunomide produced dose-dependent pulmonary toxicities that requires further investigation of the nature of injury.

lncRNA-mRNA Co-Expression and Regulation Analysis in Lung Fibroblasts from Idiopathic Pulmonary Fibrosis

“…Although cyclosporine has also been used in combination with corticosteroids at low doses in patients with IPF, its effects have not been significant [69]. Similarly, leflunomide used for the treatment of rheumatoid arthritis has been contradictory in pulmonary fibrosis since it has shown both beneficial and detrimental effects [70,71]. The duality of the effects observed for these drugs in pulmonary fibrosis seems to indicate that their effect is dose dependent; however, more research is needed.…”

The Anti-Rheumatic Drug, Leflunomide, Induces Nephrotoxicity in Mice via Upregulation of TGFβ-Mediated p53/Smad2/3 Signaling

“…LEFN use for eight weeks resulted in lung injury, and there was a marked increase in lung injury when the dose of LEFN increased. Western blot analysis revealed an increase in α-SMA, vimentin, and collagen 1 in LEFN-treated animals; there was also a dose-dependent increase of the same [ 12 ]. In the later study, elevated levels of inflammatory markers (NLRP3 and interlukin-1) were found in dose-dependent pulmonary toxicities, together with architectural structural distortion [ 12 ].…”

“…Additionally, hepatotoxicity induced by LEFN was linked to mitochondrial dysfunction at the transcript level [ 8 ], oxidative stress [ 9 , 10 ], and unfolded proteins accumulation [ 11 ]. In a recent study, LEFN induced inflammatory reactions and pulmonary toxicity in mice, together with architectural structural distortion [ 12 ].…”

Metformin Regulates Alveolar Macrophage Polarization to Protect Against Acute Lung Injury in Rats Caused by Paraquat Poisoning

“…The severity of lung injury was graded 0-4 on four aspects: 1) alveolar congestion; 2) hemorrhage; 3) infiltration of neutrophils in the alveolar space or blood vessel walls; and 4) thickening of the alveolar walls and/or formation of a transparent film. We searched for 3 observers with a certain histopathological basis to blindly observe all lungs with HE staining and grade them according to the lung injury scoring standard (El-Sherbiny et al, 2021). The lung injury score was calculated as the sum of the score of each indicator.…”