Plasmodium-Salmonella Coinfection Induces Intense Inflammatory Response, Oxidative Stress, and Liver Damage: A Mice Model Study for Therapeutic Strategy

Amuc Prevents Liver Inflammation and Oxidative Stress in Mice Challenged with Salmonella Typhimurium

BACKGROUND

Salmonella typhimurium is a pathogen that causes gastroenteritis in humans and animals. Amuc_1100 (hereafter called Amuc), the outer membrane protein of Akkermansia muciniphila, alleviates metabolic disorders and maintains immune homeostasis.

OBJECTIVE

This study was conducted to determine whether there is a protective effect of Amuc administration.

METHODS

Male 6-wk-old C57BL6J mice were randomly allocated into 4 groups: CON (control), Amuc (gavaged with Amuc, 100 μg/d for 14 d), ST (oral administration of 1.0 × 10⁶ CFU S. typhimurium on day 7), and ST + Amuc (Amuc supplementation for 14 d, S. typhimurium administration on day 7). Serum and tissue samples were collected 14 d after treatment. Histological damage, inflammatory cell infiltration, apoptosis, and protein levels of genes associated with inflammation and antioxidant stress were analyzed. Data were analyzed by 2-way ANOVA and Duncan's multiple comparisons using SPSS software.

RESULTS

The ST group mice had 17.1% lower body weight, 1.3-3.6-fold greater organ index (organ weight/body weight for organs including the liver and spleen), 10-fold greater liver damage score, and 3.4-10.1-fold enhanced aspartate transaminase, alanine transaminase, and myeloperoxidase activities, and malondialdehyde and hydrogen peroxide concentrations compared with controls (P < 0.05). The S. typhimurium-induced abnormalities were prevented by Amuc supplementation. Furthermore, the ST + Amuc group mice had 1.44-1.89-fold lower mRNA levels of proinflammatory cytokines (interleukin [Il]6, Il1b, and tumor necrosis factor-α) and chemokines (chemokine ligand [Ccl]2, Ccl3, and Ccl8) and 27.1%-68.5% lower levels of inflammation-related proteins in the liver than ST group mice (P < 0.05).

CONCLUSIONS

Amuc treatment prevents S. typhimurium-induced liver damage partly through the toll-like receptor (TLR)2/TLR4/myeloid differentiation factor 88 and nuclear factor-κB signaling as well as nuclear factor erythroid-2 related factor signaling pathways. Thus, Amuc supplementation may be effective in treating liver injury in S. typhimurium-challenged mice.

Protective Effects of Cinnamaldehyde on the Inflammatory Response, Oxidative Stress, and Apoptosis in Liver of Salmonella typhimurium-Challenged Mice

Salmonella typhimurium infection is associated with gastrointestinal disorder and cellular injury in the liver of both humans and animals. Cinnamaldehyde, the main component of essential oil from cinnamon, has been reported to have anti-inflammatory, anti-oxidative, and anti-apoptotic effects. However, it remains unknown whether cinnamaldehyde can alleviate Salmonella typhimurium infection-induced liver injury in mice. In the present study, we found that cinnamaldehyde attenuated Salmonella typhimurium-induced body weight loss, the increase of organ (liver and spleen) indexes, hepatocyte apoptosis, and the mortality rate in mice. Further study showed that cinnamaldehyde significantly alleviated Salmonella typhimurium-induced liver injury as shown by activities of alanine transaminase, aspartate transaminase, and myeloperoxidase, as well as malondialdehyde. The increased mRNA level of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IFN-γ) and chemokines (CCL2 and CCL3) induced by Salmonella typhimurium were significantly abolished by cinnamaldehyde supplementation. These alterations were associated with a regulatory effect of cinnamaldehyde on TLR2, TLR4, and MyD88. 16S rDNA sequence analysis showed that Salmonella typhimurium infection led to upregulation of the abundances of genera Akkermansia, Bacteroides, Alistipes, Muribaculum, and Prevotellaceae UCG-001, and downregulation of the abundances of genera Lactobacillus, Enterorhabdus, and Eggerthellaceae (unclassified). These alterations were reversed by cinnamaldehyde supplementation. In conclusion, cinnamaldehyde attenuated the inflammatory response, oxidative stress, and apoptosis in the liver of Salmonella typhimurium-infected mice. Supplementation of cinnamaldehyde might be a preventive strategy to alleviate liver injury caused by Salmonella typhimurium infection in humans and animals.

Will mesenchymal stem cells be future directions for treating radiation-induced skin injury?

Radiation-induced skin injury (RISI) is one of the common serious side effects of radiotherapy (RT) for patients with malignant tumors. Mesenchymal stem cells (MSCs) are applied to RISI repair in some clinical cases series except some traditional options. Though direct replacement of damaged cells may be achieved through differentiation capacity of MSCs, more recent data indicate that various cytokines and chemokines secreted by MSCs are involved in synergetic therapy of RISI by anti-inflammatory, immunomodulation, antioxidant, revascularization, and anti-apoptotic activity. In this paper, we not only discussed different sources of MSCs on the treatment of RISI both in preclinical studies and clinical trials, but also summarized the applications and mechanisms of MSCs in other related regenerative fields.