Comparative Effects of Dexamethasone and Meloxicam on Magnitude of the Acute Inflammatory Response Induced by Escherichia coli Lipopolysaccharide in Broiler Chickens

Gut microbiota intervention alleviates pulmonary inflammation in broilers exposed to fine particulate matter from broiler house

The gut microbiota of poultry is influenced by a variety of factors, including feed, drinking water, airborne dust, and footpads, among others. Gut microbiota can affect the immune reaction and inflammation in the lungs. To investigate the effect of gut microbiota variation on lung inflammation induced by PM2.5 (fine particulate matter) in broilers, 36 Arbor Acres (AA) broilers were randomly assigned to three groups: control group (CON), PM2.5 exposure group (PM), and PM2.5 exposure plus oral antibiotics group (PMA). We used non-absorbable antibiotics (ABX: neomycin and amikacin) to modify the microbiota composition in the PMA group. The intervention was conducted from the 18th to the 28th day of age. Broilers in the PM and PMA groups were exposed to PM by a systemic exposure method from 21 to 28 days old, and the concentration of PM2.5 was controlled at 2 mg/m3. At 28 days old, the lung injury score, relative mRNA expression of inflammatory factors, T-cell differentiation, and dendritic cell function were significantly increased in the PM group compared to the CON group, and those of the PMA group were significantly decreased compared to the PM group. There were significant differences in both α and β diversity of cecal microbiota among these three groups. Numerous bacterial genera showed significant differences in relative abundance among the three groups. In conclusion, gut microbiota could affect PM2.5-induced lung inflammation in broilers by adjusting the capacity of antigen-presenting cells to activate T-cell differentiation.

IMPORTANCE

Gut microbes can influence the development of lung inflammation, and fine particulate matter collected from broiler houses can lead to lung inflammation in broilers. In this study, we explored the effect of gut microbes modified by intestinal non-absorbable antibiotics on particulate matter-induced lung inflammation. The results showed that modification in the composition of gut microbiota could alleviate lung inflammation by attenuating the ability of dendritic cells to stimulate T-cell differentiation, which provides a new way to protect lung health in poultry farms.

Modulation of inflammatory and oxidative stress biomarkers due to dexamethasone exposure in chicken splenocytes

Dexamethasone (DEXA) is a potent corticosteroid, commonly used for treating inflammatory, hypersensitive and allergic conditions. It is administered to birds with tumours. Many studies were conducted on its immunosuppressive effects; however none of the similar study is available employing chicken splenocytes culture system. The present study was conducted to assess DEXA induced alterations in inflammatory and oxidative stress biomarkers in chicken splenocytes due to its in vitro exposure. The maximum non-cytotoxic dose (MNCD) was evaluated and was further used for conducting lymphocytes proliferation assay (LPA), antioxidant assays (lipid peroxidation, GSH, superoxide dismutase and nitric oxide assays) and assessment of mRNA levels of various genes (IL-1β, IL-6, IL-10, LITAF, iNOS, NF-κB1, Nrf-2, Caspase-3 and -9) through qPCR. The MNCD was determined to be 30 ng/ml in chicken splenocytes culture system. DEXA caused reduction in B and T lymphocytes proliferation indicating its immunosuppressive effects, however improved the antioxidant status of the exposed splenocytes. The expression levels of IL-1β, IL-6, iNOS, LITAF and NF-κB1 were significantly reduced while IL-10 was enhanced, which signify potent anti-inflammatory potential of DEXA. NF-κB is a major transcription factor that regulates genes responsible for both, innate and adaptive immune responses and elicits inflammation. The nuclear factor erythroid 2-related factor 2 (Nrf-2) level was found to be up-regulated. Nrf-2 plays important role in combating the oxidant stress and its increased expression could be the reason of improved antioxidant status of DEXA exposed cells. Present findings indicated that DEXA exhibited modulation in anti-inflammatory, immunomodulatory and antioxidant mediators in chicken splenocytes.

Anti-inflammatory activities of amber extract in lipopolysaccharide-induced RAW 264.7 macrophages

Amber is a type of fossil tree resin with several bioactive properties and has been traced in traditional medicines used in Russia and China. However, its anti-inflammatory activities are poorly characterized. Here, the anti-inflammatory effects of the extract of amber mined from Kaliningrad, Russia was investigated in lipopolysaccharide (LPS)-induced RAW 264.7 cells. The effect of the amber extract on cell viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Further, its effects on the production of intracellular reactive oxygen species (ROS), NO, and inflammatory cytokines were assessed by 2',7'-dichlorodihydrofluorescein diacetate staining, Griess test, and cytokine enzyme-linked immunosorbent assays, respectively. Western blotting and real-time reverse transcription-polymerase chain reaction analysis were performed to assess the mRNA and protein expression levels of the inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) interleukin-6 (IL-6), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). The translocation of the nuclear factor-kappa B (NF-κB) p65 subunit was observed by immunofluorescent staining. Amber extract negatively regulated the LPS-induced differentiation of RAW 264.7 cells to dendritic-like cells and reduced the LPS-induced increase in ROS and NO levels. It also reduced the level of mRNA and protein expressions of TNF-α, IL-6, COX-2, and iNOS in LPS-induced RAW 264.7 macrophages, in a dose-dependent manner. Furthermore, amber extract suppressed the nuclear translocation of the NF-κB p65 subunit. These findings suggest that the potent anti-inflammatory effect of the amber extract is mediated by the inhibition of the NF-κB p65 signaling pathway. Collectively, this study renders amber extract as a potential pharmacological alternative to treat inflammation-related diseases.