L‐Carnitine Protects Against Cisplatin‐Induced Activation of Human Hepatic Stellate Cells via Inflammatory Cytokines and Nitrosative Stress

Liver fibrosis, which is promoted through the activation of hepatic stellate cells (HSCs) and aggravated through oxidative and nitrosative stress induced by cisplatin, may be alleviated by L-carnitine. This study evaluates its antifibrotic efficacy in LX-1 cells through an assessment of inflammation regulation, oxidative/nitrosative stress (indicated by iNOS expression and nitric oxide production), DNA damage, and extracellular matrix (ECM) remodeling. Nitrosative stress was evaluated by measuring the expression of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) generation, both of which signify reactive nitrogen species (RNS) activity. Human hepatic stellate (LX-1) cells were treated with cisplatin (10 μM for 6 h) to induce fibrogenic stress, followed by L-carnitine (0-15 μM) exposure. Cell viability was assessed by the MTT test. To calculate the number of inflammatory cytokines, the ELISA assay was utilized. Antioxidant activity was measured using the superoxide dismutase (SOD) assay. Apoptosis was identified using DAPI staining and DNA damage was measured. Statistical analysis was conducted utilizing one-way ANOVA and Tukey's post hoc analysis (p < 0.05). L-carnitine showed a limit of concentration-dependent protection from the effects of fibrosis initiated by cisplatin. Cell viability decreased from ~85% at 2 μM to ~40% at 14 μM (p < 0.001). At 15 μM, the pro-inflammatory cytokines examined (IL-1α, IL-1β, IFN-γ, IL-6, IL-10, TGF-β1) decreased by 60%-70% (p < 0.001) with a concurrent 80% increase in the activity of SOD. A 70% decrease in the amount of DNA damage and a dose-dependent increase in apoptosis were also observed. Meanwhile, iNOS and pERK1/2 decreased ~70% and the activity of MMP-2 and MMP-9 was significantly inhibited. L-carnitine protects LX-1 hepatic stellate cells against cisplatin-induced activation by attenuating inflammation, nitrosative stress, DNA damage, and ECM remodeling. These findings suggest its therapeutic potential for preventing chemotherapy-induced hepatic fibrosis.