Expression of the PEPT1, CAT, SOD2 and GPX1 genes in the zebrafish intestine supplemented with methionine dipeptide under predation risk

Selenium elicited an enhanced anti-inflammatory effect in primary bovine endometrial stromal cells with high cortisol background

BACKGROUND

An elevated endogenous cortisol level due to the peripartum stress is one of the risk factors of postpartum bovine uterine infections. Selenium is a trace element that elicits anti-inflammation and antioxidation properties. This study aimed to reveal the modulatory effect of selenium on the inflammatory response of primary bovine endometrial stromal cells in the presence of high-level cortisol. The cells were subjected to lipopolysaccharide to establish cellular inflammation. The mRNA expression of toll-like receptor 4 (TLR4), proinflammatory factors, and selenoproteins was measured with qPCR. The activation of NF-κB and MAPK signalling pathways was detected with Western blot and immunofluorescence.

RESULTS

The pretreatment with sodium selenite (2 and 4 µΜ) resulted in a down-regulation of TLR4 and genes encoding proinflammatory factors, including interleukin (IL)-1β, IL-6, IL-8, tumour necrosis factor α, cyclooxygenase 2, and inducible nitric oxide synthase. Selenium inhibited the activation of NF-κB and the phosphorylation of mitogen-activated protein kinase kinase, extracellular signal-regulated kinase, p38MAPK and c-Jun N-terminal kinase/stress-activated protein kinase. The suppression of those genes and pathways by selenium was more significant in the presence of high cortisol level (30 ng/mL). Meanwhile the gene expression of glutathione peroxidase 1 and 4 was promoted by selenium, and was even higher in the presence of cortisol and selenium.

CONCLUSIONS

The anti-inflammatory action of selenium is probably mediated through NF-κB and MAPK, and is augmented by cortisol in primary bovine endometrial stromal cells.

Optimal DL-Methionyl-DL-Methionine Supplementation Improved Intestinal Physical Barrier Function by Changing Antioxidant Capacity, Apoptosis and Tight Junction Proteins in the Intestine of Juvenile Grass Carp (Ctenopharyngodon idella)

The present study was a part of a larger research project that aimed to investigate the effects of Met-Met supplementation on fish growth and intestinal health. This study mainly focused on the relationship between dietary Met-Met and intestinal physical barrier function in fish. Seven iso-nitrogenous diets supplemented with 2.50 g/kg DL-methionine (DL-Met) and six graded levels of Met-Met (0.00, 0.79, 1.44, 1.84, 2.22, and 2.85 g/kg) were used to feed juvenile grass carp for 10 weeks, after which a 14-day Aeromonas hydrophila challenge test was performed. The results indicated that optimum levels of Met-Met decreased intestinal oxidative damage, probably by increasing total antioxidant capacity, and the activity and gene expression levels of several antioxidant enzymes, which were closely related to the changed Nrf2/Keap1 signaling. Meanwhile, optimum levels of Met-Met decreased intestinal apoptosis and improved the intestinal tight junction, as evident by the downregulated mRNA levels of initiator and executioner caspases; the pro-apoptotic-related proteins FasL, Apaf-1, and Bax; and upregulated mRNA levels of the anti-apoptotic proteins Bcl-2, Mcl-1b, and IAP and the TJ proteins claudins, occludin, and ZOs. Furthermore, the positive effects of Met-Met on improving intestinal physical barrier function were superior to those of DL-Met in fish. These findings showed that optimal Met-Met supplementation improved intestinal physical barrier function, probably by changing antioxidant capacity, apoptosis, and tight junction proteins in fish.

Induction of developmental toxicity and cardiotoxicity in zebrafish embryos by Emamectin benzoate through oxidative stress

Emamectin benzoate (EMB) is a widely used pesticide in agriculture, but its potential risks to the environment and health have not been fully evaluated. In this study, we evaluated the toxicity of Emamectin benzoate using zebrafish model, and found that it affected early embryonic development, such as malformations and delayed hatching. Mechanistically, Emamectin benzoate increased oxidative stress by excessive production of reactive oxygen species (ROS) and abnormal activities of the antioxidant enzymes. Moreover, Emamectin benzoate exposure caused abnormalities in zebrafish heart morphology and function, such as long SV-BA distance and slow heart rate. Alterations were induced in the transcription of heart development-related genes (nkx2.5, tbx5, gata4 and myl7). In summary, our data showed that Emamectin benzoate induces developmental toxicity and cardiotoxicity in zebrafish. Our research provides new evidence on the Emamectin benzoate's toxicity and potential risk in human health.