Effects of lentinan on NF-κB activity in the liver of burn rats with sepsis

Lentinan alleviates arsenic-induced hepatotoxicity in mice via downregulation of OX40/IL-17A and activation of Nrf2 signaling

Background

Arsenic, existing ubiquitously in soil, drinking water, or food, is well known to be an environmental pollutants concerned by European Food Safety Authority. Lentinan, a beta-1,6;1,3-glucan extracts from Lentinus edodes, which has the properties of antioxidant and immunomodulation, present study explored the pharmacological effects of Lentinan on arsenic induced hepatotoxicity in mice.

Methods

Mice experiments were performed by sodium arsenite (SA) treatment or Lentinan intervention, then histopathology, ELISA, Flow Cytometry, or Western-Blotting were applied to evaluate hepatic injury, oxidative stress, CD4⁺ type 17 helper T (Th17) cells, CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs), T cells receptor OX40/CD134, IL-17A, NLRP3, Nrf2, and NQO1.

Results

SA treatment showed hepatic pathological injury and the elevations of alanine aminotransferase (ALT) or aspartate aminotransferase (AST) in serum, and induced the increases of malondialdehyde (MDA), Th17 cells, OX40 or IL-17A in liver tissues, which were consistently ameliorated by Lentinan intervention. Further, immunoblotting experiments showed that Lentinan intervention downregulated the levels of OX40, IL-17A, and NLRP3 signals, while elevated the levels of anti-oxidative Nrf2, NQO1 signals compared to arsenic treatment group. For Tregs, Lentinan intervention showed no significant difference from SA treatment group.

Conclusion

Lentinan antagonizes SA-induced hepatotoxicity in mice, may be involved in the downregulations of pro-inflammatory OX40 or IL-17A and the activation of anti-oxidative Nrf2, NQO1 signals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00557-7.

Protective Effects of Lentinan Against Lipopolysaccharide-Induced Mastitis in Mice

Mastitis is a worldwide production disease in dairy cows, which mainly affects milk yield, causing huge economic losses to dairy farmers. Lentinan is a kind of polysaccharide extracted from Lentinus edodes, which has no toxicity and possesses various pharmacological activities including antibacterial and immunomodulatory effects. Therefore, the anti-inflammatory function of lentinan on LPS-stimulated mastitis was carried out, and the mechanism involved was explored. In vivo, lentinan greatly reduced LPS-stimulated pathological injury, myeloperoxidase (MPO) activity, and the proinflammatory factor production (TNF-α and IL-1β) in mice. Further study was performed to determine the activation of the Wnt/β-catenin pathway during LPS stimulation. These results suggested that LPS-induced activation of the Wnt/β-catenin pathway was suppressed by lentinan administration. In vitro, we observed that the mouse mammary epithelial cell (mMEC) viability was not affected by lentinan treatment. As expected, LPS increased the TNF-α and IL-1β protein secretion and the activation of the Wnt/β-catenin pathway that was inhibited by lentinan administration in a dose-dependent manner in mMECs. Conclusively, lentinan exerts the anti-inflammatory function in LPS-stimulated mastitis via inhibiting the activation of the Wnt/β-catenin pathway. Thus, the results of our study also gave an insight that lentinan may serve as a potential treatment for mastitis.

Protective Effects of Melatonin against Severe Burn-Induced Distant Organ Injury: A Systematic Review and Meta-Analysis of Experimental Studies

Extensive burns result in a local wound response and distant-organ injury (DOI) caused by oxidative-stress and inflammation. Melatonin (MT) shows promise in alleviating oxidative-stress and inflammation, but its role in thermal injury is largely unexplored. The present systematic review and meta-analysis were designed to assess the effects of MT on oxidative-stress and inflammatory markers against severe burn-induced DOI. Mean difference (MD)/standard mean difference (SMD) with 95% confidence interval (CI) were estimated using fixed-effect/random-effects models. Eighteen experimental studies met the inclusion criteria. Compared with the control group, MT significantly decreased the levels of malondialdehyde (SMD, −1.03; 95% CI, −1.30, −0.76, p < 0.00001) and 4-hydroxynonenal (MD, −1.06; 95% CI, −1.57, −0.56, p < 0.0001). Additionally, MT increased the levels of glutathione (SMD, 1.94; 95% CI, 1.27, 2.61, p < 0.00001) and superoxide-dismutase (SMD, 0.76; 95% CI, 0.08, 1.45, p = 0.03). Finally, MT significantly decreased the levels of tumor necrosis factor-α (SMD, −1.34; 95% CI, −1.92 to −0.77; p < 0.00001) and C-reactive protein (MD, −12.67; 95% CI, −16.72 to −8.62; p < 0.00001). Meta-analysis indicates that severe burn followed by immediate MT (10 mg/kg) intervention shows significant beneficial effects after 24-h against DOI by regulating oxidative-stress and the inflammatory response.