Sulforaphane Attenuates Muscle Inflammation in Dystrophin-deficient mdx Mice via NF-E2-related Factor 2 (Nrf2)-mediated Inhibition of NF-κB Signaling Pathway.

Inflammation is widely distributed in patients with Duchenne muscular dystrophy and ultimately leads to progressive deterioration of muscle function with chronic muscle damage, oxidative stress, and reduced oxidative capacity. NF-E2-related factor 2 (Nrf2) plays a critical role in defending against inflammation in different tissues via activation of phase II enzyme heme oxygenase-1 and inhibition of the NF-κB signaling pathway. However, the role of Nrf2 in the inflammation of dystrophic muscle remains unknown. To determine whether Nrf2 may counteract inflammation in dystrophic muscle, we treated 4-week-old male mdx mice with the Nrf2 activator sulforaphane (SFN) by gavage (2 mg/kg of body weight/day) for 4 weeks. The experimental results demonstrated that SFN treatment increased the expression of muscle phase II enzyme heme oxygenase-1 in an Nrf2-dependent manner. Inflammation in mice was reduced by SFN treatment as indicated by decreased infiltration of immune cells and expression of the inflammatory cytokine CD45 and proinflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6 in the skeletal muscles of mdx mice. In addition, SFN treatment also decreased the expression of NF-κB(p65) and phosphorylated IκB kinase-α as well as increased inhibitor of κB-α expression in mdx mice in an Nrf2-dependent manner. Collectively, these results show that SFN-induced Nrf2 can alleviate muscle inflammation in mdx mice by inhibiting the NF-κB signaling pathway.

Sun CC ，Li SJ ，Yang CL ，Xue RL ，Xi YY ，Wang L ，Zhao QL ，Li DJ ... -  《-》

Sulforaphane alleviates muscular dystrophy in mdx mice by activation of Nrf2.

Sulforaphane (SFN), one of the most important isothiocyanates in the human diet, is known to have chemo-preventive and antioxidant activities in different tissues via activation of nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated induction of antioxidant/phase II enzymes, such as heme oxygenase-1 and NAD(P)H quinone oxidoreductase 1. However, its effects on muscular dystrophy remain unknown. This work was undertaken to evaluate the effects of SFN on Duchenne muscular dystrophy. Four-week-old mdx mice were treated with SFN by gavage (2 mg·kg body wt(-1)·day(-1) for 8 wk), and our results demonstrated that SFN treatment increased the expression and activity of muscle phase II enzymes NAD(P)H quinone oxidoreductase 1 and heme oxygenase-1 with a Nrf2-dependent manner. SFN significantly increased skeletal muscle mass, muscle force (∼30%), running distance (∼20%), and GSH-to-GSSG ratio (∼3.2-fold) of mdx mice and decreased the activities of plasma creatine phosphokinase (∼45%) and lactate dehydrogenase (∼40%), gastrocnemius hypertrophy (∼25%), myocardial hypertrophy (∼20%), and malondialdehyde levels (∼60%). Furthermore, SFN treatment also reduced the central nucleation (∼40%), fiber size variability, and inflammation and improved the sarcolemmal integrity of mdx mice. Collectively, these results show that SFN can improve muscle function and pathology and protect dystrophic muscle from oxidative damage in mdx mice associated with Nrf2 signaling pathway, which indicate Nrf2 may have clinical implications for the treatment of patients with muscular dystrophy.

Sun C ，Yang C ，Xue R ，Li S ，Zhang T ，Pan L ，Ma X ，Wang L ，Li D ... -  《-》

Sulforaphane mitigates muscle fibrosis in mdx mice via Nrf2-mediated inhibition of TGF-β/Smad signaling.

Sulforaphane (SFN), an activator of NF-E2-related factor 2 (Nrf2), has been found to have an antifibrotic effect on liver and lung. However, its effects on dystrophic muscle fibrosis remain unknown. This work was undertaken to evaluate the effects of SFN-mediated activation of Nrf2 on dystrophic muscle fibrosis. Male mdx mice (age 3 mo) were treated with SFN by gavage (2 mg/kg body wt per day) for 3 mo. Experimental results demonstrated that SFN remarkably attenuated skeletal and cardiac muscle fibrosis as indicated by reduced Sirius Red staining and immunostaining of the extracellular matrix. Moreover, SFN significantly inhibited the transforming growth factor-β (TGF-β)/Smad signaling pathway and suppressed profibrogenic gene and protein expressions such as those of α-smooth muscle actin (α-SMA), fibronectin, collagen I, plasminogen activator inhibitor-1 (PAI-1), and tissue inhibitor metalloproteinase-1 (TIMP-1) in an Nrf2-dependent manner. Furthermore, SFN significantly decreased the expression of inflammatory cytokines CD45, TNF-α, and IL-6 in mdx mice. In conclusion, these results show that SFN can attenuate dystrophic muscle fibrosis by Nrf2-mediated inhibition of the TGF-β/Smad signaling pathway, which indicates that Nrf2 may represent a new target for dystrophic muscle fibrosis.

Sun C ，Li S ，Li D 《-》

Investigating the Potential for Sulforaphane to Attenuate Gastrointestinal Dysfunction in mdx Dystrophic Mice.

Swiderski K ，Read SJ ，Chan AS ，Chung JD ，Trieu J ，Naim T ，Koopman R ，Lynch GS ... -  《-》

Anti-Inflammatory Effect of Sulforaphane on LPS-Activated Microglia Potentially through JNK/AP-1/NF-κB Inhibition and Nrf2/HO-1 Activation.

Subedi L ，Lee JH ，Yumnam S ，Ji E ，Kim SY ... -  《Cells》