Effects of dietary Chitosan oligosaccharides supplementation on Th17/Treg balance and gut microbiota of early weaned pigeon squabs.

Our previous study found that early weaning is associated with decreased growth performance, intestinal barrier impairment, and an imbalance in Th17/Treg in pigeon squabs. Chitosan oligosaccharides (COS) has been substantiated to regulate gut microbiota and restore Th17/Treg equilibrium in mammals, thereby ameliorating growth performance. However, the potential effects of COS in altricial birds remain unclear. Three hundred healthy 7-day-old American king pigeon squabs were selected with similar body weights and randomly divided into 5 groups. The 5 treatment groups were as follows: the control group (CON), fed with artificial pigeon milk; 4 supplementation groups, fed with artificial pigeon milk +100 (COS1), 150 (COS2), 200 (COS3), and 250 (COS4) mg/kg COS, respectively. Results showed that dietary supplementation of COS significantly enhanced the growth performance of weaned squabs. Compared to the CON group, the COS groups exhibited increased villus length and villus area in the jejunum and ileum, accompanied by improvements in morphological structure and mucosal permeability. COS was found to reduce the levels of Th17-associated cytokines and increase the levels of Treg-associated cytokines. COS downregulated the expression of retinoic acid receptor-related orphan receptor C (RORC), a key transcription factor of Th17 cells, while upregulated the expression of Forkhead box protein P3 (FOXP3), a key transcription factor of Treg cells. Dietary COS supplementation increased gut bacterial diversity, altered the relative abundance of several bacteria taxa and enhanced the concentration of short-chain fatty acids (SCFA). Correlation analysis demonstrated a close association between gut microbiota, SCFAs, and indicators related to the Th17/Treg balance. Moreover, we found that SCFAs correlated more strongly with Th17/Treg-related indexes than gut microbiota. These results demonstrated that COS could relieve early weaning stress in pigeon squabs and the optimal dosage of dietary COS supplementation was suggested to be 200 mg/kg. In addition, COS had a protective effect on maintaining intestinal immune balance by modulating microbiota and Th17/Treg related signaling pathways, in which SCFAs might play a crucial role as messengers.

Coated sodium butyrate ameliorates high-energy and low-protein diet induced hepatic dysfunction via modulating mitochondrial dynamics, autophagy and apoptosis in laying hens.

BACKGROUND: Fatty liver hemorrhagic syndrome (FLHS), a fatty liver disease in laying hens, poses a grave threat to the layer industry, stemming from its ability to trigger an alarming plummet in egg production and usher in acute mortality among laying hens. Increasing evidence suggests that the onset and progression of fatty liver was closely related to mitochondria dysfunction. Sodium butyrate was demonstrated to modulate hepatic lipid metabolism, alleviate oxidative stress and improve mitochondrial dysfunction in vitro and mice models. Nevertheless, there is limited existing research on coated sodium butyrate (CSB) to prevent FLHS in laying hens, and whether and how CSB exerts the anti-FLHS effect still needs to be explored. In this experiment, the FLHS model was induced by administering a high-energy low-protein (HELP) diet in laying hens. The objective was to investigate the effects of CSB on alleviating FLHS with a focus on the role of CSB in modulating mitochondrial function. METHODS: A total of 288 healthy 28-week-old Huafeng laying hens were arbitrarily allocated into 4 groups with 6 replicates each, namely, the CON group (normal diet), HELP group (HELP diet), CH500 group (500 mg/kg CSB added to HELP diet) and CH750 group (750 mg/kg CSB added to HELP diet). The duration of the trial encompassed a period of 10 weeks. RESULTS: The result revealed that CSB ameliorated the HELP-induced FLHS by improving hepatic steatosis and pathological damage, reducing the gene levels of fatty acid synthesis, and promoting the mRNA levels of key enzymes of fatty acid catabolism. CSB reduced oxidative stress induced by the HELP diet, upregulated the activity of GSH-Px and SOD, and decreased the content of MDA and ROS. CSB also mitigated the HELP diet-induced inflammatory response by blocking TNF-α, IL-1ß, and F4/80. In addition, dietary CSB supplementation attenuated HELP-induced activation of the mitochondrial unfolded protein response (UPRmt), mitochondrial damage, and decline of ATPase activity. HELP diet decreased the autophagosome formation, and downregulated LC3B but upregulated p62 protein expression, which CSB administration reversed. CSB reduced HELP-induced apoptosis, as indicated by decreases in the Bax/Bcl-2, Caspase-9, Caspase-3, and Cyt C expression levels. CONCLUSIONS: Dietary CSB could ameliorate HELP diet-induced hepatic dysfunction via modulating mitochondrial dynamics, autophagy, and apoptosis in laying hens. Consequently, CSB, as a feed additive, exhibited the capacity to prevent FLHS by modulating autophagy and lipid metabolism.

Glutaredoxin 2 protects lens epithelial cells from epithelial-mesenchymal transition by suppressing mitochondrial oxidative stress-related upregulation of integrin-linked kinase.

Glutaredoxin 2 (Grx2), a mitochondrial glutathione-dependent oxidoreductase, is crucial for maintaining redox homeostasis and cellular functions in the lens. The oxidative stress-induced epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) is related to posterior capsule opacification. In this study, we investigated the effects of Grx2 on oxidative stress-induced EMT in LECs during posterior capsule opacification. We found that Grx2 expression was substantially decreased during the EMT of LECs and in a mouse model of cataract surgery. Deletion of Grx2 aggravated the generation of reactive oxygen species, including those that are mitochondria-derived, and promoted the proliferation and EMT of the LECs. This was reversed by Grx2 overexpression. In vivo, proteomic liquid chromatography-mass spectrometry analysis showed that integrin-linked kinase (ILK) was significantly upregulated in the lens posterior capsule of a Grx2 knockout (KO) mouse model. Compared with that of the wild-type group, the expression of ILK and EMT markers was increased in the Grx2 KO group which was reversed in the Grx2 knock-in group. Inhibition of ILK partially blocked Grx2 knockdown-induced EMT and prevented the increased phosphorylation of Akt and GSK-3ß and the nuclear translocation of ß-catenin in the Grx2 KO group. Finally, inhibition of the Wnt/ß-catenin pathway partially blocked the Grx2 knockdown-induced EMT. In conclusion, we demonstrated that Grx2 protects LECs from oxidative stress-related EMT by regulating the ILK/Akt/GSK-3ß axis.

Dietary Supplementation of Chitosan Oligosaccharide-Clostridium butyricum Synbiotic Relieved Early-Weaned Stress by Improving Intestinal Health on Pigeon Squabs (Columba livia).

According to a previous study, we had found that early weaning causes harm to growth performance, intestinal morphology, activity of digestive enzymes, and antioxidant status in pigeon squabs (Columba livia). Chitosan oligosaccharides (COS) and Clostridium butyricum have been reported to have great potential to improve the growth performance and intestinal health of early-weaned animals. Therefore, the aim of this study is to explore whether dietary supplementation with COS-C. butyricum synbiotic could relieve early-weaned stress by evaluating its effects on growth performance and intestinal health in pigeon squabs. A total of 160 squabs (weaned at 7 days of age) were randomly divided into 5 groups: the control group, fed with artificial crop milk; the COS supplementation group, fed with artificial crop milk + 150 mg/kg COS; and three synbiotic supplementation groups, fed with artificial crop milk + 150 mg/kg COS + 200, 300, and 400 mg/kg C. butyricum. The results showed that a diet supplemented with COS-C. butyricum synbiotic benefitted the growth performance of early-weaned squabs; even so the differences were not significant among the five groups (p > 0.05). In addition, dietary supplementation of 150 mg/kg COS + 300~400 mg/kg C. butyricum significantly improved the intestinal morphology (especially villus surface area and the ratio of villus height to crypt depth), the activity of digestive enzymes (lipase, trypsin, and leucine aminopeptidase) in duodenum contents, and the production of total short-chain fatty acids and acetic acid in ileum content (p < 0.05). Additionally, dietary supplementation of 150 mg/kg COS + 400 mg/kg C. butyricum benefitted gut health by improving the antioxidant capacity (glutathione peroxidase and total antioxidant capacity) and cytokine status (IL-4 and IL-10) (p < 0.05), as well as by improving the intestinal microbiota diversity. In conclusion, our results revealed that dietary supplementation with synbiotic (150 mg/kg COS + 300~400 mg/kg C. butyricum) could relieve early-weaned stress by maintaining intestinal health in pigeon squabs.

Early Weaning Stress Induces Intestinal Microbiota Disturbance, Mucosal Barrier Dysfunction and Inflammation Response Activation in Pigeon Squabs.

Early weaning stress has been reported to impair intestinal health in mammals. Like mammals, weaning of the pigeon squab, an altricial bird, is associated with social, environmental and dietary stress. However, understanding of weaning stress on intestinal functions is very limited in altricial birds, especially in squabs. This study was aimed to evaluate the effects of early weaning stress on intestinal microbiota diversity, architecture, permeability, the first line defense mechanisms, mucosal barrier functions, and immune cell responses. A total of 192 newly hatched squabs were randomly allocated into two groups, one weaned on day 7 and the other remained with the parent pigeons. Mucosal tissue and digesta in ileum, as well as blood samples, were collected from squabs (n = 8) on days 1, 4, 7, 10, and 14 postweaning. Our results showed that weaning stress induced immediate and long-term deleterious effects on both growth performance and intestinal barrier functions of squabs. Early weaning significantly increased ileal bacterial diversity and alters the relative abundance of several bacteria taxa. Weaning stress can also cause morphological and functional changes in ileum, including an atrophy in villi, an increase in permeability, and a variation in the mRNA expression of genes encoding mucins, immunoglobulins, tight junction proteins, toll-like receptors, and cytokines, as well as the concentration of secretory IgA. We concluded that the impaired intestinal barrier functions accompanied with early weaning stress seems to be the main reason for the poor growth rate after weaning in squabs. In addition, the disturbance of intestinal microbiota of early weaning stress in squabs coincided with dysfunction of intestinal mucosal barrier and activation of inflammation cell responses that were possibly mediated via the activation of toll-like receptors.

Both UFH and NAH alleviate shedding of endothelial glycocalyx and coagulopathy in LPS-induced sepsis.

Sepsis commonly progresses to disseminated intravascular coagulation and induces the activation of heparanase (HPA) and the shedding of endothelial glycocalyx constituents, including syndecan-1 (SDC-1) and heparan sulphate (HS). However, the degradation of glycocalyx and its association with coagulation disorders remains undetermined. The present study aimed to evaluate the effect of unfractionated heparin (UFH) and N-acetylheparin (NAH), which is a non-anticoagulant heparin derivative, on endothelial glycocalyx and coagulation function in a lipopolysaccharide (LPS)-induced sepsis rat model, and to compare the differences observed in coagulation function between UFH and NAH. Experimental rats were randomly assigned to four groups: Control; LPS; UFH + LPS; and NAH + LPS. Rats were administered UFH or NAH and subsequently, ~1 min later, administered LPS (10 mg/kg; intravenous). The blood and lung tissues of rats were collected 0.5, 2 and 6 h after LPS injection, and were used for subsequent analysis. The results demonstrated that HPA activity and SDC-1 and HS levels increased, and this increase was associated with inflammatory cytokines and coagulation/fibrinolysis markers in the sepsis rat model. Histopathological examination was performed, and the lung injury score and lung wet/dry ratio indicated that UFH and NAH also significantly improved lung tissue injury. The results of the ELISA analysis demonstrated that UFH and NAH treatment: i) significantly decreased the levels of inflammatory cytokines including tumor necrosis factor-α and interleukin-6; ii) inhibited HPA activity and protected the integrity of the glycocalyx, which was identified by decreased HS and SDC-1 levels; and iii) decreased the levels of prothrombin fragment 1+2, thrombin-antithrombin complex, and plasminogen activator inhibitor-1 and increased the levels of fibrinogen and antithrombin-III. Preconditioning with UFH decreased the plasma activated partial thromboplastin time. These results indicated that UFH and NAH may alleviate sepsis-induced coagulopathy, and this effect may have been due to an inhibition of HPA activity and decrease in the shedding of the endothelial glycocalyx.

Evaluation of the bioactivity about anti-sca-1/basic fibroblast growth factor-urinary bladder matrix scaffold for pelvic reconstruction.

Introduction and hypothesis: Pelvic support structure injury is the major cause of pelvic organ prolapse. At present, polypropylene-based filler material has been suggested as a common method to treat pelvic organ prolapse. However, it cannot functionally rehabilitate the pelvic support structure. In addition to its poor long-term efficiency, the urinary bladder matrix was the most suitable biological scaffold material for pelvic floor repair. Here, we hypothesize that anti-sca-1 monoclonal antibody and basic fibroblast growth factor were cross-linked to urinary bladder matrix to construct a two-factor bioscaffold for pelvic reconstruction. METHODS: Through a bispecific cross-linking reagent, sulfosuccinimidyl 4-[N-maleimidomethyl] cyclohexane-1-carboxylate (sulfo-smcc) immobilized anti-sca-1 and basic fibroblast growth factor to urinary bladder matrix. Then scanning electron microscope and plate reader were used to detect whether the anti-sca-1/basic fibroblast growth factor-urinary bladder matrix scaffold was built successfully. After that, the capacity of enriching sca-1 positive cells was measured both in vitro and in vivo. In addition, we evaluated the differentiation capacity and biocompatibility of the scaffold. Finally, western blotting was used to detect the level of fibulin-5 protein. RESULTS: The scanning electron microscope and plate reader revealed that the double-factor biological scaffold was built successfully. The scaffold could significantly enrich a large number of sca-1 positive cells both in vitro and in vivo, and obviously accelerate cells and differentiate functional tissue with good biocompatibility. Moreover, the western blotting showed that the scaffold could improve the expression of fibulin-5 protein. CONCLUSION: The anti-sca-1/basic fibroblast growth factor-urinary bladder matrix scaffold revealed good biological properties and might serve as an ideal scaffold for pelvic reconstruction.

Neferine Protects Endothelial Glycocalyx via Mitochondrial ROS in Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome.

Damage to the endothelial glycocalyx is a critical factor in increased pulmonary vascular permeability, which is the basic pathological feature of acute respiratory distress syndrome (ARDS). Neferine (Nef), a bisbenzylisoquinoline alkaloid isolated from green seed embryos of Nelumbo nucifera Gaertn, has extensive pharmacological activity. In this study, we showed that Nef reduced lung-capillary permeability, down-regulated the production of cytokines (IL-1ß, IL-6, TNF-α, and IL-10) and inhibited the activation of the NF-κB signaling pathway in mice with lipopolysaccharide (LPS)-induced ARDS. Further analysis indicated that Nef provided protection against endothelial glycocalyx degradation in LPS-induced ARDS mice (in vivo) and in LPS-stimulated human umbilical vein endothelial cells (in vitro). The glycocalyx-protective effect of Nef may be initiated by suppressing the production of mitochondrial ROS (mtROS) and decreasing oxidative damage. Nef was also found to promote glycocalyx restoration by accelerating the removal of mtROS in endothelial cells in LPS-induced ARDS. These results suggested the potential of Nef as a therapeutic agent for ARDS associated with Gram-negative bacterial infections and elucidated the mechanisms underlying the protection and restoration of the endothelial glycocalyx.

Decitabine and 5-azacitidine both alleviate LPS induced ARDS through anti-inflammatory/antioxidant activity and protection of glycocalyx and inhibition of MAPK pathways in mice.

Decitabine (5-aza-2'-deoxycytidine, DAC) and 5-azacitidine (Aza), an inhibitor of DNA methyltransferases, possess a wide range of anti-metabolic and anti-cancer activities. This study examined the effects of DAC and Aza on inflammatory and oxidative injuries, as well as on glycocalyx and MAPK signaling pathways, in a LPS-stimulated ARDS mouse model. Results of ELISA revealed that DAC and Aza significantly inhibited the production of TNF-α and IL-1ß and prevented LPS-induced elevation of myeloperoxidase and malondialdehyde levels in serum. The W/D ratio of lung and histopathologic examination with hematoxylin and eosin staining showed that DAC and Aza pretreatment substantially improved lung tissue injury. DAC and Aza reduced the level of glycocalyx degradation products (e.g., heparan sulfate and haluronic acid) and protected glycocalyx integrity. Western blot assay demonstrated that DAC and Aza both significantly suppressed LPS-induced activation of the MAPK signaling pathways by blocking the phosphorylation of JNK, ERK and P38 in lung tissues. Bisulfite sequencing PCR and real time-PCR showed that DAC reversed the RASSF1A promoter hypermethylation and furthermore elevated the expression of RASSF1A, which is a tumor suppressor that regulates MAPK signaling pathway. These results suggested that DAC inhibited the MAPK signaling pathway in LPS-induced ARDS mice might via demethylation in RASSF1A promoter region and by restoring its expression. This study highlighted the close relationship between DNA methylation and the development and progression of ARDS.

Ulinastatin attenuates pulmonary endothelial glycocalyx damage and inhibits endothelial heparanase activity in LPS-induced ARDS.

Acute respiratory distress syndrome (ARDS) is a syndrome of acute respiratory failure characterized by major pathologic mechanisms of increased microvascular permeability and inflammation. The glycocalyx lines on the endothelial surface, which determines the vascular permeability, and heparanase play pivotal roles in the degradation of heparan sulfate (HS). HS is the major component of the glycocalyx. The aim of this study is to examine the effects of Ulinastatin (UTI) on vascular permeability and pulmonary endothelial glycocalyx dysfunction induced by lipopolysaccharide (LPS). In our study, C57BL/6 mice and human umbilical vein endothelial cells were stimulated with LPS to induce injury models. After 6 h of LPS stimulation, pulmonary pathological changes, pulmonary edema, and vascular permeability were notably attenuated by UTI. UTI inhibited LPS-induced endothelial glycocalyx destruction and significantly decreased the production of HS as determined by ELISA and immunofluorescence. UTI also reduced the active form of heparanase (50 kDa) expression and heparanase activity. Moreover, lysosome pH was investigated because heparanase (65 kDa) can be reduced easily in its active form at 50 kDa in a low pH environment within lysosome. Results showed that UTI could inhibit LPS-induced pH elevation in lysosome. In conclusion, UTI protects pulmonary endothelial glycocalyx integrity and inhibits heparanase activity during LPS-induced ARDS.

Astilbin alleviates LPS-induced ARDS by suppressing MAPK signaling pathway and protecting pulmonary endothelial glycocalyx.

Acute respiratory distress syndrome (ARDS) is a devastating disorder that is characterized by increased vascular endothelial permeability and inflammation. Unfortunately, no effective treatment beyond supportive care is available for ARDS. Astilbin, a flavonoid compound isolated from Rhizoma Smilacis Glabrae, has been used for anti-hepatic, anti-arthritic, and anti-renal injury treatments. This study examined the effects of Astilbin on pulmonary inflammatory activation and endothelial cell barrier dysfunction caused by Gram-negative bacterial endotoxin lipopolysaccharide (LPS). Endothelial cells from human umbilical veins or male Kunming mice were pretreated with Astilbin 24h before LPS stimulation. Results showed that Astilbin significantly attenuated the pulmonary histopathological changes and neutrophil infiltration 6h after the LPS challenge. Astilbin suppressed the activities of myeloperoxidase and malondialdehyde, as well as the expression of tumor necrosis factor-α and interleukin-6 in vivo and in vitro. As indices of pulmonary edema, lung wet-to-dry weight ratios, were markedly decreased by Astilbin pretreatment. Western blot analysis also showed that Astilbin inhibited LPS-induced activation of mitogen-activated protein kinase (MAPK) pathways in lung tissues. Furthermore, Astilbin significantly inhibited the activity of heparanase and reduced the production of heparan sulfate in the blood serum as determined by ELISA. These findings indicated that Astilbin can alleviate LPS-induced ARDS, which potentially contributed to the suppression of MAPK pathway activation and the degradation of endothelial glycocalyx.