S-allylmercapto-N-acetylcysteine protects bone cells from oxidation and improves femur microarchitecture in healthy and diabetic mice

S-Allylmercapto-N-Acetylcysteine (ASSNAC) Attenuates Osteoporosis in Ovariectomized (OVX) Mice

Osteoporosis is a bone-debilitating disease, demonstrating a higher prevalence in post-menopausal women due to estrogen deprivation. One of the main mechanisms underlying menopause-related bone loss is oxidative stress. S-allylmercapto-N-acetylcysteine (ASSNAC) is a nuclear factor erythroid 2-related factor 2 (Nrf2) activator and cysteine supplier, previously shown to have anti-oxidation protective effects in cultured cells and animal models. Here, we studied the therapeutic potential of ASSNAC with and without Alendronate in ovariectomized (OVX) female mice. The experimental outcome included (i) femur and L3 lumbar vertebra morphometry via Micro-Computed Tomography (μCT); (ii) bone remodeling (formation vs. resorption); and (iii) oxidative stress markers in bone marrow (BM) cells. Four weeks after OVX, there was a significant bone loss that remained evident after 8 weeks, as demonstrated via µCT in the femur (cortical and trabecular bone compartments) and vertebra (trabecular bone). ASSNAC at a dose of 50 mg/Kg/day prevented bone loss after the four-week treatment but had no significant effect after 8 weeks, while ASSNAC at a dose of 20 mg/Kg/day significantly protected against bone loss after 8 weeks of treatment. Alendronate prevented ovariectomy-induced bone loss, and combining it with ASSNAC further augmented this effect. OVX mice demonstrated high serum levels of both C-terminal cross-linked telopeptides of type I collagen (CTX) (bone resorption) and procollagen I N-terminal propeptide (P1NP) (bone formation) after 2 weeks, and these returned to control levels after 8 weeks. Alendronate, ASSNAC and their combination decreased CTX and increased P1NP. Alendronate induced oxidative stress as reflected by decreased glutathione and increased malondialdehyde (MDA) levels, and combining it with ASSNAC partially attenuated these changes. These results portray the therapeutic potential of ASSNAC for the management of post-menopausal osteoporosis. Furthermore, ASSNAC ameliorates the Alendronate-associated oxidative stress, suggesting its potential to prevent Alendronate side effects as well as improve its bone-protective effect.

S-allylmercapto-N-acetylcysteine ameliorates pulmonary fibrosis in mice via Nrf2 pathway activation and NF-κB, TGF-β1/Smad2/3 pathway suppression

Pulmonary fibrosis (PF) is a chronic lung disease characterised by alveolar inflammatory injury, alveolar septal thickening, and eventually fibrosis. Patients with severe Coronavirus Disease 2019 (COVID-19) may have left a certain degree of pulmonary fibrosis. PF is commonly caused by oxidative imbalance and inflammatory damage. S-allylmercapto-N-acetylcysteine (ASSNAC) exhibits anti-oxidative and anti-inflammatory effects in other diseases. However, the pharmacodynamics of ASSNAC remain unclear for PF. This investigation aimed to evaluate the efficacy and mechanism of ASSNAC against PF. The PF model was established by TGF-β1 stimulating HFL-1 cells in vitro. ASSNAC exhibited the potential to inhibit fibroblast transformation into myofibroblasts. Also, in the PF mice model with bleomycin (BLM), the sodium salt of ASSNAC (ASSNAC-Na) inhalation was treated. ASSNAC remarkably improved mice's lung tissue structure and collagen deposition. The important indicator proteins of PF, collagen Ⅰ, collagen Ⅲ, and α-SMA significantly decreased in the ASSNAC treated groups. Besides, ASSNAC attenuated oxidative stress by reversing glutathione (GSH), superoxide dismutase (SOD) levels and interfering with Nrf2/NOX4 signaling pathways. ASSNAC showed an anti-inflammatory effect by reducing the number of inflammatory cells and inflammatory cytokines, such as TNF-α and IL-6, and blocking the NF-κB signaling pathway. ASSNAC inhibited fibroblast differentiation by blocking the TGF-β1/Smad2/3 signaling pathway. This study implicates that ASSNAC alleviates pulmonary fibrosis through fighting against oxidative stress, reducing inflammation and inhibiting fibroblast differentiation.