Chlorella vulgaris ameliorates sodium nitrite-induced hepatotoxicity in rats

Metabolic reprogramming of corn oligopeptide in regulating sodium nitrite-induced canine hepatocyte injury via TGF/NF-κB signaling pathways and aminoacyl-tRNA biosynthesis

Sodium nitrite (SN), a prevalent food preservative, is known to precipitate hepatotoxicity upon exposure. This study elucidates the hepatoprotective effects of corn oligopeptide (COP) and vitamin E (VE) against SN-induced hepatic injury in canine hepatocytes. Canine liver cells were subjected to SN to induce hepatotoxicity, followed by treatment with COP and VE. Evaluations included assays for cell viability, oxidative stress markers, apoptosis, and inflammatory cytokines. Additionally, transcriptomic and metabolomic analyses were performed to delineate the underlying molecular mechanisms. The findings demonstrated that COP and VE significantly ameliorated SN-induced cytotoxicity, oxidative stress, and apoptosis. It was evidenced by restored cell viability, enhanced antioxidant enzyme activity, reduced cytoplasmic enzyme leakage, and decreased levels of malondialdehyde and inflammatory cytokines, with COP showing superior efficacy. The RNA sequencing revealed that COP treatment suppressed the SN-activated aminoacyl-tRNA biosynthesis pathway and TGF-β/NF-κB signaling pathways, thereby mitigating amino acid depletion, apoptosis, and inflammation. Moreover, COP treatment upregulated genes associated with protein folding, bile acid synthesis, and DNA repair. Metabolomic analysis corroborated these results, showing that COP restored amino acid levels and enhanced bile acid metabolism, alleviating SN-induced metabolic disruptions. These findings offered significant insights into the protective mechanisms of COP underscoring its prospective application in treating liver injuries.

The effect and mechanism of combined exposure of MC-LR and NaNO2 on liver lipid metabolism

Microcystin-LR (MC-LR) and sodium nitrite (NaNO2) co-exist in the environment and are hepatotoxic. The liver has the function of lipid metabolism, but the impacts and mechanisms of MC-LR and NaNO2 on liver lipid metabolism are unclear. Therefore, we established a chronic exposure model of Balb/c mice and used LO2 cells for in vitro verification to investigate the effects and mechanisms of liver lipid metabolism caused by MC-LR and NaNO2. The results showed that after 6 months of exposure to MC-LR and NaNO2, the lipid droplets content was increased, and the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were raised in the liver (P < 0.05). Moreover, MC-LR and NaNO2 synergistically induced hepatic oxidative stress by decreasing total superoxide dismutase (T-SOD) activity and glutathione (GSH) levels and increasing malondialdehyde (MDA) content levels. In addition, the levels of Nrf2, HO-1, NQO1 and P-AMPK was decreased and Keap1 was increased in the Nrf2/HO-1 pathway. The key factors of lipid metabolism, SREBP-1c, FASN and ACC, were up-regulated in the liver. More importantly, there was a combined effect on lipid deposition of MC-LR and NaNO2 co-exposure. In vitro experiments, MC-LR and NaNO2-induced lipid deposition and changes in lipid metabolism-related changes were mitigated after activation of the Nrf2/HO-1 signaling pathway by the Nrf2 activator tertiary butylhydroquinone (TBHQ). Additionally, TBHQ alleviated the rise of reactive oxygen species (ROS) in LO2 cells induced by MC-LR and NaNO2. Overall, our findings indicated that MC-LR and NaNO2 can cause abnormal liver lipid metabolism, and the combined effects were observed after MC-LR and NaNO2 co-exposure. The Nrf2/HO-1 signal pathway may be a potential target for prevention and control of liver toxicity caused by MC-LR and NaNO2.

Exposure to oxyfluorfen-induced hematobiochemical alterations, oxidative stress, genotoxicity, and disruption of sex hormones in male African catfish and the potential to confront by Chlorella vulgaris

The present study evaluated the effect of chronic exposure to oxyfluorfen (OXY) on different physiological responses of male African catfish, Clarias gariepinus, and the ameliorative effect of Chlorella vulgaris. The fish (160 ± 5.10 g) were exposed to 1/20 LC₅₀ of OXY (0.58 mg/L) for 60 consecutive days with or without co-administration of C. vulgaris (25 g/kg diet) in triplicate groups. The results revealed that chronic exposure to a sublethal level of OXY induced severe anemia and leukopenia. OXY-exposed fish experienced hypoproteinemia, marked lower AchE levels, and a significant increase in glucose, liver, and kidney function biomarkers. The DNA fragmentation of the liver increased by 15 % in fish compared to the control. On the other hand, lipid peroxidation, superoxide dismutase, and catalase activities were markedly increased in the liver and testes homogenates of the OXY-exposed fish. Meanwhile, total antioxidant capacity and glutathione S-transferase levels declined in the same tissues. Exposure to OXY induced a significant reduction in testosterone and luteinizing hormone levels and a significant increase in follicle stimulating hormone and estradiol. Meanwhile, C. vulgaris dietary supplementation succeeded in alleviating the negative impact of OXY on hematobiochemical parameters and restoring the antioxidant balance in the liver and testes. Furthermore, it ameliorated endocrine disruption and repaired sex hormone levels. In conclusion, exposure to OXY could induce systemic stress, oxidative stress, and endocrine disruption in male C. gariepinus. The dietary supplementation of C. vulgaris could be a potential protective strategy against the toxicity of OXY.

Dietary Sodium Nitrite Causes Similar Modifications to Splenic Inflammatory Gene Expression as a High-Fat Diet

Sodium nitrite (NaNO₂) is a widely used food additive. The present study compared the outcomes from intakes of dietary NaNO₂ and a high-fat diet (HFD), and assessed their combined effects on inflammatory gene expression in the immune tissues of the mouse. In experiment I, mice were fed a standard low-fat diet (LFD) without or with NaNO₂ (0.02 and 0.08%, w/w) for 11 wk. In experiment II, mice were fed an LFD without or with NaNO₂ (0.02%) or HFD without or with NaNO₂ (0.02%) for 11 wk. Inflammatory gene expression in the immune tissues was then measured. NaNO₂ consumption and HFD feeding each resulted in increased splenic mRNAs for cell markers of neutrophils (Ngp, NE, Ly6g, Mpo) and eosinophils (Epo, Ear6), and an S100 family member (S100A8). In contrast, NaNO₂ consumption and HFD feeding each resulted in decreased splenic mRNAs for cell markers of macrophages (Emr1, Itgax, CD68, CD206, Dectin-1, TLRs 4, 6, and 7), T- (CD3, CD4), NK- (CD56) and B-cells (CD20, CD40), pro- and anti-inflammatory cytokines (TNF-α, IL-6, IL-1β, IFN-γ, IL-18, IL-10, TGF-β), interleukin receptor antagonists (IL1ra, IL6ra) and cell adhesion molecules (ICAM-1, VCAM-1). However, dietary NaNO₂ combined with HFD feeding caused no further decrease in these transcript levels compared with dietary NaNO₂ alone. These NaNO₂- or HFD-induced modifications were less profound in the liver and abdominal adipose tissues than in the spleen. These findings indicate that dietary NaNO₂ has similar modulatory effects to HFD feeding on splenic inflammatory genes.

Hepatoprotective effect of Thymus vulgaris extract on sodium nitrite-induced changes in oxidative stress, antioxidant and inflammatory marker expression

The herb thyme (Thymus vulgaris) has multiple therapeutic uses. In this study, we explored how T. vulgaris leaf extract protects liver cells against sodium nitrite-(NaNO₂) induced oxidative stress. Mice were divided into four groups; each group received one of the following treatments orally: saline; T. vulgaris extract alone; NaNO₂ alone; or T. vulgaris extract + NaNO₂. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), reduced glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), IL-1β, IL-6, TNF-α, and total proteins were measured in serum using standard methods. TNF-α, hemooxygenase-1 (HO-1), thioredoxin, SOD, and GSH synthase, all of which are linked to oxidative stress, were measured using quantitative real-time PCR (qRT-PCR). In mice treated with T. vulgaris extract, the effect of NaNO₂ on ALT and AST levels and total proteins was reduced, and its effect on antioxidant levels was reversed. Normally, NaNO₂ causes hepatocyte congestion and severe hepatic central vein congestion. Tissues in the mice treated with T. vulgaris were restored to normal conditions. Our results demonstrate that NaNO₂-induced hepatic injury is significantly reduced by pretreatment with T. vulgaris extract, which protects against hepatic oxidative stress and its associated genes at the biochemical, molecular, and cellular levels.