Responses of growth performance,antioxidant function,small intestinal morphology and mRNA expression of jejunal tight junction protein to dietary iron in yellow-feathered broilers

This study aimed to investigate the dose-effect of iron on growth performance,antioxidant function.intestinal morphology,and mRNA expression of jejunal tight junction protein in 1-to21-d-old yellow-feathered broilers.A total of 7201-d-old yellow-feathered maleb roilers were allocated to 9 treatments with 8 replicate cages of 10 birds per cage.The dietary treatments were consisted of a basal diet(contained 79.6 mg Fe kg^(-1))supplemented with 0,20,40,60,80,160,320,640,and 1,280 mg Fe kg^(-1)in the form of FeSO_(4)·7H_(2)O.Compared with the birds in the control group,birds supplemented with 20mg Fe kg^(-1)had higher average daily gain(ADG)(P<0.0001).Adding 640 and 1,280 mg Fe kg^(-1)significantly decreased ADG(P<0.0001)and average daily feed intake(ADFI)(P<0.0001)compared with supplementation of 20mg Fe kg^(-1).Malondialdehyde(MDA)concentration in plasma and duodenum increased linearly(P<0.0001),but MDA concentration in liver and jejunum increased linearly(P<0.05)or quadratically(P<0.05)with increased dietary Fe concentration.The villus height(VH)in duodenum and jejunum,and the ratio of villus height to crypt depth(V/C)in duodenum decreased linearly(P?0.05)as dietary Feincreased.As dietary Fe increased,the jejunal relative mRNA abundance of claudin-1 decreased linearly(P=0.001),but the jejunal relative mRNA abundance of zona occludens-1(ZO-1)and occludin decreased linearly(P?0.05)or quadratically(P?0.05).Compared with the supplementation of 20 mg Fe kg^(-1),the supplementation of640 mg Fe kg^(-1)or higher increased(P?0.05)MDA concentrations in plasma,duodenum,and jejunum,decreased VH in the duodenum and jejunum,and the addition of 1,280 mg Fe kg^(-1)reduced(P?0.05)the jejunal tight junction protein(claudin-1,ZO-1,occludin)mRNA abundance.In summary,640 mg of supplemental Fe kg^(-1)or greater was associated with decreased growth performance,increased oxidative stress,disrupted intestinal morphology,and reduced mRNA expression of jejunal tight junction protein.

Dietary protocatechuic acid ameliorates inflammation and up-regulates intestinal tight junction proteins by modulating gut microbiota in LPS-challenged piglets

Background: Weaning is one of the major factors that cause stress and intestinal disease in piglets. Protocatechuic acid(PCA) is an active plant phenolic acid which exists in Chinese herb, Duzhong(Eucommia ulmoides Oliver), and is also considered as the main bioactive metabolite of polyphenol against oxidative stress and inflammation. This study aimed to investigate the effect of PCA on growth performance, intestinal barrier function, and gut microbiota in a weaned piglet model challenged with lipopolysaccharide(LPS).Methods: Thirty-six piglets(Pig Improvement Company line 337 × C48, 28 d of age, 8.87 kg ± 0.11 kg BW) were randomly allocated into 3 treatments and fed with a basal diet(CTL), a diet added 50 mg/kg of aureomycin(AUR), or a diet supplemented with 4000 mg/kg of PCA, respectively. The piglets were challenged with LPS(10 μg/kg BW) on d 14 and d 21 by intraperitoneal injection during the 21-d experiment. Animals(n = 6 from each group) were sacrificed after being anesthetized by sodium pentobarbital at 2 h after the last injection of LPS. The serum was collected for antioxidant indices and inflammatory cytokines analysis, the ileum was harvested for detecting mRNA and protein levels of tight junction proteins by PCR and immunohistochemical staining, and the cecum chyme was collected for intestinal flora analysis using 16 S rRNA gene sequencing.Results: Dietary supplementation of PCA or AUR significantly increased the expression of tight junction proteins including ZO-1 and claudin-1 in intestinal mucosa, and decreased the serum levels of thiobarbituric acid reactive substances(TBARS) and IL-6, as compared with CTL group. In addition, PCA also decreased the serum levels of IL-2 and TNF-α(P < 0.05). Analysis of gut microbiota indicated that PCA increased the Firmicutes/Bacteroidetes ratio(P < 0.05). Spearman's correlation analysis at the genus level revealed that PCA reduced the relative abundance of Prevotella 9, Prevotella 2, Holdemanella, and Ruminococcus torques group(P < 0.05), and increased the relative abundance of Roseburia and Desulfovibrio(P < 0.05), whereas AUR had no significant effect on these bacteria.Conclusions: These results demonstrated that both PCA and AUR had protective effect on oxidative stress, inflammation and intestinal barrier function in piglets challenged with LPS, and PCA potentially exerted the protective function by modulating intestinal flora in a way different from AUR.

New tight junction protein 2 variant causing progressive familial intrahepatic cholestasis type 4 in adults: A case report

BACKGROUND Progressive familial intrahepatic cholestasis(PFIC)encompasses a group of autosomal recessive disorders with high morbidity and mortality.Variants in the gene encoding tight junction protein-2(TJP2)have been linked to PFIC type 4(PFIC4),which predominantly presents in childhood.However,there are only limited data from adults with TJP2-related PFIC4.We report a family with an autosomal recessive disorder with a novel variant in the TJP2 gene in adults with very variable expression of PFIC4.CASE SUMMARY The index patient presented at 19 years old with liver cirrhosis and variceal bleeding and was treated with endoscopic banding and beta-blockers.In 2018,he developed primary liver cancer that was treated with radiofrequency ablation followed by liver transplantation in 2019.Genetic testing revealed a novel homozygous TJP2 variant causing PFIC4(TJP2([NM_004817.3]:c.[3334C>T];[3334C>T])).The consanguineous family consists of the father and mother(both heterozygous)and their 12 children,of which five carry the variant in a homozygous state;however,these five siblings have highly variable expression of PFIC4.Two homozygous brothers had cirrhosis and portal hypertension at diagnosis at the ages of 19 and 36.Two other homozygous brothers,age 23 and 19,and the homozygous sister,age 21,have elevated liver enzymes but presently no cirrhosis,which may suggest an age-dependent penetrance.In addition,five sisters had severe and mild intrahepatic cholestasis of pregnancy and carry the TJP2 variant in a homozygous and heterozygous state,respectively.CONCLUSION This novel TJP2 variant is associated with PFIC4 causing severe liver disease with cirrhosis and primary liver cancer in adolescents/adults.

Cinnamicaldehyde regulates the expression of tight junction proteins and amino acid transporters in intestinal porcine epithelial cells

Background： Cinnamicaldehyde（CA） is a key flavor compound in cinnamon essential oil possessing various bioactivities. Tight junction（TJ） proteins are vital for the maintenance of intestinal epithelial barrier function,transport, absorption and utilization of dietary amino acids and other nutrients. In this study, we tested the hypothesis that CA may regulate the expression of TJ proteins and amino acid transporters in intestinal porcine epithelial cells（IPEC-1） isolated from neonatal pigs.Results： Compared with the control, cells incubated with 25 μmol/L CA had increased transepithelial electrical resistance（TEER） and decreased paracellular intestinal permeability. The beneficial effect of CA on mucosal barrier function was associated with enhanced protein abundance for claudin-4, zonula occludens（ZO）-1, ZO-2, and ZO-3. Immunofluorescence staining showed that 25 μmol/L CA promoted the localization of claudin-1 and claudin-3 to the plasma membrane without affecting the localization of other TJ proteins, including claudin-4, occludin,ZO-1, ZO-2, and ZO-3, compared with the control cells. Moreover, protein abundances for rBAT, xCT and LAT2 in IPEC-1 cells were enhanced by 25 μmol/L CA, while that for EAAT3 was not affected.Conclusions： CA improves intestinal mucosal barrier function by regulating the distribution of claudin-1 and claudin-3 in enterocytes, as well as enhancing protein abundance for amino acid transporters rBAT, xCT and LAT2 in enterocytes. Supplementation with CA may provide an effective nutritional strategy to improve intestinal integrity and amino acid transport and absorption in piglets.

Effects of Simulated Weightlessness on Tight Junction Protein Occludin and Zonula Occluden-1 Expression Levels in the Intestinal Mucosa of Rats

This study investigated the tight junction（TJ） protein expression of the intestinal mucosa in a rat tail-suspension model under simulated weightlessness.Twenty-four Wistar rats were randomly divided into three groups：CON group（n=8）,control; SUS-14 d group（n=8）,tail-suspension for 14 days; SUS-21 d group（n=8）,tail-suspension for 21 days.Occludin and Zonula Occluden-1（ZO-1） expression levels were determined by immunohistochemical analysis and mRNA fluorescent quantitative PCR.Plasma levels of diamine oxidase（DAO） and d-lactate were determined using enzymatic spectrophotometry.Immunohistochemical results for occludin and ZO-1 showed disruption of the TJs in the intestinal mucosa in SUS-14 d and SUS-21 d groups.The expression levels of occludin and ZO-1 in SUS-21 d group were lower than those in SUS-14 d group,and significantly lower than those in CON group（Occldin：0.86±0.02 vs 1.01±0.03 vs 1.63±0.03 and ZO-1：0.82±0.01 vs 1.00±0.02 vs 1.55±0.01,P〈0.01）.Moreover,the levels of plasma DAO and d-lactate in SUS-21 d group were higher than those in SUS-14 d group,and significantly higher than those in CON group（DAO：27.58±0.49 vs 20.74±0.49 vs 12.94±0.21 and d-lactate：37.86±0.74 vs 28.26±1.01 vs 17.76±0.91,P〈0.01）.There were significant negative correlations between occludin or ZO-1 expression levels and DAO（r2=0.9014,r2=0.9355,P〈0.01） or d-lactate levels（r2=0.8989,r2=0.9331,P〈0.01）.Occludin and Zo-1 were reduced in intestinal mucosa both in mRNA and protein levels in the rat tail-suspension model.The significant negative correlations between expression levels of TJs and plasma levels of DAO or d-lactate support the hypothesis that intestinal permeability is increased due to a decrease in TJ protein expression during tail-suspension from 14 days to 21 days.

Side-stream smoking reduces intestinal inflammation and increases expression of tight junction proteins

AIM:To investigate the effect of side-stream smoking on gut microflora composition,intestinal inflammation and expression of tight junction proteins.METHODS:C57BL/6 mice were exposed to side-stream cigarette smoking for one hour daily over eight weeks.Cecal contents were collected for microbial composition analysis.Large intestine was collected for immunoblotting and quantitative reverse transcriptase polymerase chain reaction analyses of the inflammatory pathway and tight junction proteins.RESULTS:Side-stream smoking induced significant changes in the gut microbiota with increased mouse intestinal bacteria,Clostridium but decreased Fermicutes(Lactoccoci and Ruminococcus),Enterobacteriaceae family and Segmented filamentous baceteria compared to the control mice.Meanwhile,side-stream smoking inhibited the nuclear factor-κB pathway with reduced phosphorylation of p65 and IκBα,accompanied with unchanged mRNA expression of tumor necrosis factor-α or interleukin-6.The contents of tight junction proteins,claudin3 and ZO2 were up-regulated in the large intestine of mice exposed side-stream smoking.In addition,side-stream smoking increased c-Jun N-terminal kinase and p38 MAPK kinase signaling,while inhibiting AMPactivated protein kinase in the large intestine.CONCLUSION:Side-stream smoking altered gut microflora composition and reduced the inflammatory response,which was associated with increased expression of tight junction proteins.

Protective Effect of Simvastatin on Impaired Intestine Tight Junction Protein ZO-1 in a Mouse Model of Parkinson's Disease

Summary： Recently, several studies showed that gastrointestinal tract may be associated with patho- physiology of Parkinson＇s disease （PD）. Intestine tight junction protein zonula occluden-1 （ZO-1） is an important component of intestinal barrier which can be degraded by matrix metallopeptidase 9 （MMP-9）. In our previous study, a significant decline in ZO-1 was observed along with enhanced MMP-9 activity in the duodenum and distal colon of 1-methyl-4-phenyl-l,2,3,6-tetrahydropyridine （MPTP）-intoxicated mice. In this study, the protective effect of simvastatin on ZO-1 was investigated using an MPTP mouse model of PD. Seven days after the end of MPTP application, the expression level of ZO-1 was evaluated by immunohistochemistry. The protein expression levels of ZO-1 and MMP9 were detected by Western blotting. Meanwhile, MMP-9 activity was analyzed by gelatin zymography. MPTP treatment led to a decrease in the expression of ZO-1, which was accompanied by elevated MMP-9 activity. Treatment with simvastatin could partly reverse the MPTP-induced changes in ZO-I expression and reduce MMP-9 protein and activity. Taken together, these findings suggest that simvas- tatin administration may partially reverse the impairment of ZO-1 induced by MPTP via inhibiting the activity of MMP9, fortify the impaired intestinal barrier and limit gut-derived toxins that＇pass across the intestinal barrier.

Diabetes exacerbates inflammatory bowel disease in mice with dietinduced obesity

BACKGROUND The increased prevalence of inflammatory bowel disease(IBD)among patients with obesity and type 2 diabetes suggests a causal link between these diseases,potentially involving the effect of hyperglycemia to disrupt intestinal barrier integrity.AIM To investigate whether the deleterious impact of diabetes on the intestinal barrier is associated with increased IBD severity in a murine model of colitis in mice with and without diet-induced obesity.METHODS Mice were fed chow or a high-fat diet and subsequently received streptozotocin to induce diabetic-range hyperglycemia.Six weeks later,dextran sodium sulfate was given to induce colitis.In select experiments,a subset of diabetic mice was treated with the antidiabetic drug dapagliflozin prior to colitis onset.Endpoints included both clinical and histological measures of colitis activity as well as histochemical markers of colonic epithelial barrier integrity.RESULTS In mice given a high-fat diet,but not chow-fed animals,diabetes was associated with significantly increased clinical colitis activity and histopathologic markers of disease severity.Diabetes was also associated with a decrease in key components that regulate colonic epithelial barrier integrity(colonic mucin layer content and epithelial tight junction proteins)in diet-induced obese mice.Each of these effects of diabetes in diet-induced obese mice was ameliorated by restoring normoglycemia.CONCLUSION In obese mice,diabetes worsened clinical and pathologic outcomes of colitis via mechanisms that are reversible with treatment of hyperglycemia.Hyperglycemia-induced intestinal barrier dysfunction offers a plausible mechanism linking diabetes to increased colitis severity.These findings suggest that effective diabetes management may decrease the clinical severity of IBD.

Rifaximin Prevents Intestinal Barrier Dysfunction and Alleviates Liver Injury in MCT-induced HSOS Mice

Objective Rifaximin is an effective component of treatment strategies for liver and intestinal diseases.However,the efficacy of rifaximin in hepatic sinusoidal obstruction syndrome(HSOS)has not been explored.The present study aimed to investigate the efficacy and mechanism of rifaximin in HSOS.Methods An HSOS model was established in mice through the administration of monocrotaline(MCT,800 mg/kg),and part of the HSOS mice were intragastrically administered with rifaximin.Then,the efficacy of rifaximin in HSOS was evaluated based on the liver pathological findings,liver proinflammatory cytokines,and alanine aminotransferase and aspartate aminotransferase levels.The Ussing chamber was used to evaluate the intestinal permeability,and tight junction(TJ)proteins were measured by Western blotting and real-time polymerase chain reaction to evaluate the intestinal barrier integrity.Then,the serum proinflammatory cytokine levels were evaluated by enzyme-linked immunosorbent assay.Afterwards,an in vitro experiment was performed to determine the relationship between rifaximin and TJ proteins.Results Rifaximin effectively alleviated the MCT-induced HSOS liver injury,suppressed the expression of liver proinflammatory cytokines,and reduced the serum levels of tumor necrosis factor-alpha and interleukin-6.Furthermore,rifaximin reduced the intestinal permeability,improved the intestinal barrier integrity,and promoted the expression of TJ proteins.Conclusion The results revealed that the intestinal barrier integrity was destroyed in MCT-induced HSOS.The significant alleviation of MCT-induced HSOS induced by rifaximin might be correlated to the repairment of intestinal barrier integrity via the regulation of the TJ protein expression.

Protective effect and mechanism insight of purified Antarctic krill phospholipids against mice ulcerative colitis combined with bioinformatics

Antarctic krill oil is functional oil and has a complex phospholipids composition that poses difficulties in elucidating its effect mechanism on ulcerative colitis(UC).The mechanism of UC action was studied by bioinformatics,and the therapeutic effect of Antarctic krill phospholipids(APL)on dextran sulfate sodium(DSS)-induced colitis mice was verified.GO functional enrichment analysis uncovered an enrichment of these genes in the regulation of cell-cell adhesion,membrane region,signaling receptor activator activity,and cytokine activity.Meanwhile,the KEGG results revealed the genes were enriched in the TNF signaling pathway,pathogenic Escherichia coli infection,inflammatory bowel disease and tight junction.Animal experiments showed that APL treatment alleviated the UC symptoms and reduced inflammatory damage.Meanwhile,the expressions of the tight junction(TJ)proteins,ZO-1 and occludin,were restored,and the levels of IL-6 and TNF-αwere reduced.Moreover,Firmicutes/Bacteroidetes ratio in the intestinal microbiota was regulated,and the contents of short-chain fatty acids metabolites were raised.These findings would provide an insight for the beneficial effects of APL and dietary therapy strategies for UC.

Effect of Tebuconazole exposure on oral Atenolol absorption in rats,based on bile acid homeostasis

Objective:This study is aimed to explore the effect of triazole fungicide tebuconazole(TEB)exposure on the oral absorption behavior of atenolol(AT),based on the homeostasis of bile acids(BAs).Methods:TEB was daily gavaged to rats with 3 mg/kg dose for 28 days to establish the TEB-exposure rat model.The amounts of glycocholic acid,glycochenodeoxycholic acid,taurocholic acid and taurine deoxycholic acid in the small intestine contents of normal and TEB-exposure rats were detected by LC-MS/MS.AT(10 mg/kg)were gavaged to the normal and TEB-exposure rats,and then blood were collected from orbital venous plexus at predetermined time-points.The concentration of AT in plasma was detected by LC-MS/MS,and the pharmacokinetic parameters were calculated by the DAS pharmacokinetic software.An intestinal circulation perfusion model was established in normal rats,and perfused with the perfusates containing the model drug of fluorescein and the BAs with the same compositions as the normal/TEB-exposure rats.After perfusion,the absorption and permeability of fluorescein in intestine were detected,as well as the oxidative stress status and ZO-1 expression level in the intestinal tissues.Results:Compared with normal rats,TEB-exposure increased the amounts of glycocholic acid,glycochenodeoxycholic acid,taurocholic acid and taurine deoxycholic acid in intestine significantly(P<0.001).In TEB-exposure rats,the maximum plasma concentration and area under the curve of AT were increased significantly than those of normal rats(P<0.05),and the peak time was significantly delayed(P<0.05).The TEB-induced BAs homeostasis perturbance increased intestinal permeability,and this effect was associated with the elevation of oxidative stress and the down-regulation of intercellular tight junction proteins in intestinal tissues.Conclusion:TEB-exposure can affect the oral absorption behavior of AT,which is probably related with the intestinal BAs homeostasis perturbance,thus it might affect the clinical efficacy and safety of this drug.

Dexmedetomidine attenuates traumatic brain injury: action pathway and mechanisms

Traumatic brain injury induces potent inflammatory responses that can exacerbate secondary blood-brain barrier（BBB） disruption, neuronal injury, and neurological dysfunction. Dexmedetomidine is a novel α2-adrenergic receptor agonist that exert protective effects in various central nervous system diseases. The present study was designed to investigate the neuroprotective action of dexmedetomidine in a mouse traumatic brain injury model, and to explore the possible mechanisms. Adult male C57 BL/6 J mice were subjected to controlled cortical impact. After injury, animals received 3 days of consecutive dexmedetomidine therapy（25 μg/kg per day）. The modified neurological severity score was used to assess neurological deficits. The rotarod test was used to evaluate accurate motor coordination and balance. Immunofluorescence was used to determine expression of ionized calcium binding adapter molecule-1, myeloperoxidase, and zonula occluden-1 at the injury site. An enzyme linked immunosorbent assay was used to measure the concentration of interleukin-1β（IL-1β）, tumor necrosis factor α, and IL-6. The dry-wet weight method was used to measure brain water content. The Evans blue dye extravasation assay was used to measure BBB disruption. Western blot assay was used to measure protein expression of nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3（NLRP3）, caspase-1 p20, IL-1β, nuclear factor kappa B（NF-κB） p65, occluding, and zonula occluden-1. Flow cytometry was used to measure cellular apoptosis. Results showed that dexmedetomidine treatment attenuated early neurological dysfunction and brain edema. Further, dexmedetomidine attenuated post-traumatic inflammation, up-regulated tight junction protein expression, and reduced secondary BBB damage and apoptosis. These protective effects were accompanied by down-regulation of the NF-κB and NLRP3 inflammasome pathways. These findings suggest that dexmedetomidine exhibits neuroprotective effects against acute（3 days） post-traumatic inflammatory responses, potentially via suppression of NF-κB and NLRP3 inflammasome activation.

Effects of protein sources and levels in antibiotic-free diets on diarrhea,intestinal morphology, and expression of tight junctions in weaned piglets

This study examined effects of dietary protein sources and levels on intestinal health of 21 to 35 d-old weaned piglets fed antibiotics-free diets. A total of 150 weaned piglets(21 d of age) were allotted to 5 dietary treatment groups. Diets were formulated, based on corn-soybean meal, with different protein sources(fish meal and soy protein concentrate) to provide different dietary CP levels. Piglets within 5 dietary treatments were fed diets as follows, respectively: 1) control diet of 17% CP(control); 2) 19% CP diets formulated with more soy protein concentrate(SPC19); 3) fish meal(FM19); 4) 23.7% CP diets formulated with more soy protein concentrate(SPC23); 5) fish meal(FM23). The results showed that piglets from control group had higher ADG and lower incidence of diarrhea compared with those of other groups(P < 0.05). The incidence of diarrhea of piglets in FM19 group was lower than those from SPC23 group and FM23 group(P < 0.05). With the higher CP levels, villous height and villous height to crypt depth ratio of piglets in the duodenum and jejunum were decreased(P < 0.05), but crypt depth was increased(P < 0.05). Comparing control group and other groups, we found the expression of inflammatory cytokines interleukin-1β(IL-1β) and interferon-γ(IFN-γ) were increased(P < 0.05) in the jejunum and colon of piglets, as did cystic fibrosis transmembrane conductance regulators(CFTR) in the distal colon. The relative transcript abundance of Zonula occludens-1(ZO-1) in the jejunum, and occludin in the jejunum and ileum of piglets fed 23.7% CP diets were reduced compared with those fed control diet(P < 0.05). In conclusion, the 17% CP diet without in-feed antibiotics helped improve growth performance and relief of diarrhea of 21 to 35 d-old weaned piglets. Dietary CP level, rather than its source(either fish meal or soy protein concentrate), has more significant impacts on the growth performance and intestinal health of 21 to 35 d-old weaned piglets when fed antibiotics-free diets.

Combined probiotic bacteria promotes intestinal epithelial barrier function in interleukin-10-gene-deficient mice

AIM: To investigate the protective effects of combinations of probiotic (Bifico) on interleukin (IL)-10-gene-deficient (IL-10 KO) mice and Caco-2 cell monolayers.

Urolithin A alleviates blood-brain barrier disruption and attenuates neuronal apoptosis following traumatic brain injury in mice

Urolithin A(UA)is a natural metabolite produced from polyphenolics in foods such as pomegranates,berries,and nuts.UA is neuroprotective against Parkinson’s disease,Alzheimer’s disease,and cerebral hemorrhage.However,its effect against traumatic brain injury remains unknown.In this study,we established adult C57BL/6J mouse models of traumatic brain injury by controlled cortical impact and then intraperitoneally administered UA.We found that UA greatly reduced brain edema;increased the expression of tight junction proteins in injured cortex;increased the immunopositivity of two neuronal autophagy markers,microtubule-associated protein 1A/B light chain 3A/B(LC3)and p62;downregulated protein kinase B(Akt)and mammalian target of rapamycin(mTOR),two regulators of the phosphatidylinositol 3-kinase(PI3K)/Akt/mTOR signaling pathway;decreased the phosphorylation levels of inhibitor of NFκB(IκB)kinase alpha(IKKα)and nuclear factor kappa B(NFκB),two regulators of the neuroinflammation-related Akt/IKK/NFκB signaling pathway;reduced blood-brain barrier permeability and neuronal apoptosis in injured cortex;and improved mouse neurological function.These findings suggest that UA may be a candidate drug for the treatment of traumatic brain injury,and its neuroprotective effects may be mediated by inhibition of the PI3K/Akt/mTOR and Akt/IKK/NFκB signaling pathways,thus reducing neuroinflammation and enhancing autophagy.

Dual therapy with zinc acetate and rifaximin prevents from ethanolinduced liver fibrosis by maintaining intestinal barrier integrity

BACKGROUND Hepatic overload of gut-derived lipopolysaccharide dictates the progression of alcoholic liver disease(ALD)by inducing oxidative stress and activating Kupffer cells and hepatic stellate cells through toll-like receptor 4 signaling.Therefore,targeting the maintenance of intestinal barrier integrity has attracted attention for the treatment of ALD.Zinc acetate and rifaximin,which is a nonabsorbable antibiotic,had been clinically used for patients with cirrhosis,particularly those with hepatic encephalopathy,and had been known to improve intestinal barrier dysfunction.However,only few studies focused on their efficacies in preventing the ALD-related fibrosis development.AIM To investigate the effects of a combined zinc acetate with rifaximin on liver fibrosis in a mouse ALD model.METHODS To induce ALD-related liver fibrosis,female C57BL/6J mice were fed a 2.5%(v/v)ethanol-containing Lieber-DeCarli liquid diet and received intraperitoneal carbon tetrachloride(CCl4)injection twice weekly(1 mL/kg)for 8 wk.Zinc acetate(100 mg/L)and/or rifaximin(100 mg/L)were orally administered during experimental period.Hepatic steatosis,inflammation and fibrosis as well as intestinal barrier function were evaluated by histological and molecular analyses.Moreover,the direct effects of both agents on Caco-2 barrier function were assessed by in vitro assays.RESULTSIn the ethanol plus CCl4-treated mice,combination of zinc acetate and rifaximin attenuated oxidative lipid peroxidation with downregulation of Nox2 and Nox4.This combination significantly inhibited the Kupffer cells expansion and the proinflammatory response with blunted hepatic exposure of lipopolysaccharide and the toll-like receptor 4/nuclear factor kB pathway.Consequently,liver fibrosis and hepatic stellate cells activation were efficiently suppressed with downregulation of Mmp-2,-9,-13,and Timp1.Both agents improved the atrophic changes and permeability in the ileum,with restoration of tight junction proteins(TJPs)by decreasing the expressions of tumor necrosis factorαand myosin light chain kinase.In the in vitro assay,both agents directly reinforced ethanol or lipopolysaccharide-stimulated paracellular permeability and upregulated TJPs in Caco-2 cells.CONCLUSION Dual therapy with zinc acetate and rifaximin may serve as a strategy to prevent ALD-related fibrosis by maintaining intestinal barrier integrity.

Hyperoside protects the blood-brain barrier from neurotoxicity of amyloid beta 1–42

Mounting evidence indicates that amyloid β protein（Aβ） exerts neurotoxicity by disrupting the blood-brain barrier（BBB） in Alzheimer＇s disease. Hyperoside has neuroprotective effects both in vitro and in vivo against Aβ. Our previous study found that hyperoside suppressed Aβ1-42-induced leakage of the BBB, however, the mechanism remains unclear. In this study, bEnd.3 cells were pretreated with 50, 200, or 500 μM hyperoside for 2 hours, and then exposed to Aβ1-42 for 24 hours. Cell viability was determined using 3-（4,5-dimethyl-2-thiazolyl）-2,5-diphenyl-2-H-tetrazolium bromide assay. Flow cytometry and terminal deoxynucleotidyl transferase-mediated d UTP nick-end labeling assay were used to analyze cell apoptosis. Western blot assay was carried out to analyze expression levels of Bax, Bcl-2, cytochrome c, caspase-3, caspse-8, caspase-9, caspase-12, occludin, claudin-5, zonula occludens-1, matrix metalloproteinase-2（MMP-2）, and MMP-9. Exposure to Aβ1-42 alone remarkably induced bEnd.3 cell apoptosis; increased ratios of cleaved caspase-9/caspase-9, Bax/Bcl-2, cleav ed caspase-8/caspase-8, and cleaved caspase-12/caspase-12; increased expression of cytochrome c and activity of caspase-3; diminished levels of zonula occludens-1, claudin-5, and occludin; and increased levels of MMP-2 and MMP-9. However, hyperoside pretreatment reversed these changes in a dose-dependent manner. Our findings confirm that hyperoside alleviates fibrillar Aβ1-42-induced BBB disruption, thus offering a feasible therapeutic application in Alzheimer＇s disease.

CircLphn3 protects the blood-brain barrier in traumatic brain injury

Circular RNAs(circRNAs)are a new and large group of non-coding RNA molecules that are abundantly expressed in the central nervous system.However,very little is known about their roles in traumatic brain injury.In this study,we firstly screened differentially expressed circ RNAs in normal and injured brain tissues of mice after traumatic brain injury.We found that the expression of circ Lphn3 was substantially decreased in mouse models of traumatic brain injury and in hemin-treated b End.3(mouse brain cell line)cells.After overexpressing circ Lphn3 in b End.3 cells,the expression of the tight junction proteins,ZO-1,ZO-2,and occludin,was upregulated,and the expression of mi R-185-5 p was decreased.In b End.3 cells transfected with mi R-185-5 p mimics,the expression of ZO-1 was decreased.Dual-luciferase reporter assays showed that circ Lphn3 bound to mi R-185-5 p,and that mi R-185-5 p bound to ZO-1.Additionally,circ Lphn3 overexpression attenuated the hemin-induced high permeability of the in vitro b End.3 cell model of the blood-brain barrier,while mi R-185-5 p transfection increased the permeability.These findings suggest that circ Lphn3,as a molecular sponge of mi R-185-5 p,regulates tight junction proteins'expression after traumatic brain injury,and it thereby improves the permeability of the blood-brain barrier.This study was approved by the Animal Care and Use Committee of Chongqing Medical University of China(approval No.2021-177)on March 22,2021.

Long-term effect of subacute ruminal acidosis on the morphology and function of rumen epithelial barrier in lactating goats

Grain-induced subacute ruminal acidosis(SARA)impairs rumen epithelial barrier function,but it is yet to be determined if SARA can cause persistent damage to the morphology and function of the rumen epithelial barrier.The objective of the present study was to investigate if SARA has persistent effects on the morphological structure and permeability of ruminal epithelium and the expression of the genes involved in epithelial barrier function using a lactating goat model.Twelve mid-lactating Saanen goats with rumen cannulas were randomly assigned to 1 of 2 groups:control group(Ctrl,n=4)fed a basal diet with a non-fiber carbohydrate(NFC)to neutral detergent fiber(NDF)ratio of 1.40,and SARA group(SARA,n=8)fed the same basal diet but with increasing NFC to NDF ratio from 1.4 to 1.79,2.31,and 3.23 overtime to induce SARA.At the end of the SARA challenge(post-SARA),4 goats were randomly selected from the SARA group and fed only hay mixture ad libitum for another 4 weeks to allow for restitution(post-SARA).Ruminal pH was continuously recorded to monitor the severity of SARA.Samples of the ventral ruminal epithelium were collected after slaughter to examine the structural and functional changes of the ruminal epithelium using transmission electron microscopy(TEM),Ussing chambers,qRT-PCR,and Western bolt analyses.Compared with the Ctrl group,ruminal papilla length,width,surface area and thickness of stratum corneum increased(P<0.05),while stratum spinosum and basale thickness,and total depth of the epithelium decreased(P<0.05)in the SARA group.These changes diminished or tended to return to the levels of the Ctrl group in the post-SARA group(P>0.05).The SARA challenge also decreased cellular junction and widened the intercellular space between epithelial cells.Rumen transepithelial short-circuit current(Isc),tissue conductance(Gt),and mucosa-to-serosa flux of paracellular horseradish peroxidase(HRP)all increased(P<0.05)both in the SARA and post-SARA groups,which indicates that SARA can induce a sustained increase in epithelial permeability and barrier dysfunction.Moreover,the mRNA and protein expressions of CLDN1,OCLN and ZO-1 were down-regulated(P<0.01)in both the SARA and post-SARA groups.The results of this study showed that SARA could result in sustained epithelial barrier dysfunction,at both structural and functional levels,which is associated with decreased expression of rumen epithelial tight junction proteins,and the restitution of rumen epithelial barrier function is slower than that of its morphology.

Propofol protects against blood-spinal cord barrier disruption induced by ischemia/reperfusion injury

Propofol has been shown to exert neuroprotective effects on the injured spinal cord.However,the effect of propofol on the blood-spinal cord barrier（BSCB） after ischemia/reperfusion injury（IRI） is poorly understood.Therefore,we investigated whether propofol could maintain the integrity of the BSCB.Spinal cord IRI（SCIRI） was induced in rabbits by infrarenal aortic occlusion for 30 minutes.Propofol,30 mg/kg,was intravenously infused 10 minutes before aortic clamping as well as at the onset of reperfusion.Then,48 hours later,we performed histological and m RNA/protein analyses of the spinal cord.Propofol decreased histological damage to the spinal cord,attenuated the reduction in BSCB permeability,downregulated the m RNA and protein expression levels of matrix metalloprotease-9（MMP-9） and nuclear factor-κB（NF-κB）,and upregulated the protein expression levels of occludin and claudin-5.Our findings suggest that propofol helps maintain BSCB integrity after SCIRI by reducing MMP-9 expression,by inhibiting the NF-κB signaling pathway,and by maintaining expression of tight junction proteins.