• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.234.3-235
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• 2003

The aim of this study is to evaluate the permeability of PEG-conjugated salmon calcitonin (sCT) across monolayers of Caco-2 cells that represent a model of the intestinal barrier. Caco-2 cells were grown to confluency on a permeable polycarbonate membrane to permit transport through it. Permeability experiments were performed with native-sCT and PEG-conjugated sCT (PEG M.W. 2000) at various concentrations (5uM, 10uM, 25uM, 50uM, 100uM) in the apical to basolateral direction. The barrier properties were assessed by detecting transport of markder molecules ($^3$H-mannitol) and by measuring transepithelial electrical resistance (TEER). (omitted)

• Asian-Australasian Journal of Animal Sciences
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• 제22권12호
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• pp.1667-1675
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• 2009

This study was conducted to determine whether L-arginine (Arg) supplementation could improve intestinal function in weaned pigs after an Escherichia coli lipopolysaccharide (LPS) challenge. Treatments included: i) non-challenged control (CONTR, pigs fed a control diet and injected with sterile saline); ii) LPS-challenged control (LPS, pigs fed the same control diet and challenged by injection with Escherichia coli LPS); iii) LPS+0.5% Arg (pigs fed a 0.5% Arg diet and challenged with LPS); and iv) LPS+1.0% Arg (pigs fed a 1.0% Arg diet and challenged with LPS). On d 16, pigs were administrated with LPS or sterile saline. D-xylose was orally administrated at 2 h following LPS challenge, and blood samples were collected at 3 h following LPS challenge. At 6 h post-challenge, pigs were sacrificed and intestinal mucosa samples were collected. Supplementation of Arg attenuated LPS-induced damage in gut digestive and barrier functions, as indicated by an increase in ileal lactase activity, and duodenal and ileal diamine oxidase activities (p<0.05). Arg administration also prevented the increase of jejunal malondialdehyde content and the decrease of ileal superoxide dismutase activity by LPS challenge (p<0.05). Furthermore, the jejunal nitric oxide level and inducible nitric oxide synthase activity were also improved after Arg supplementation (p<0.05). These results indicate that Arg supplementation has beneficial effects in alleviating the impairment of gut function induced by LPS challenge.

• Asian-Australasian Journal of Animal Sciences
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• 제29권8호
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• pp.1075-1082
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• 2016

Modern livestock production became highly intensive and large scaled to increase production efficiency. This production environment could add stressors affecting the health and growth of animals. Major stressors can include environment (air quality and temperature), nutrition, and infection. These stressors can reduce growth performance and alter immune systems at systemic and local levels including the gastrointestinal tract. Heat stress increases the permeability, oxidative stress, and inflammatory responses in the gut. Nutritional stress from fasting, antinutritional compounds, and toxins induces the leakage and destruction of the tight junction proteins in the gut. Fasting is shown to suppress pro-inflammatory cytokines, whereas deoxynivalenol increases the recruitment of intestinal pro-inflammatory cytokines and the level of lymphocytes in the gut. Pathogenic and viral infections such as Enterotoxigenic E. coli (ETEC) and porcine epidemic diarrhea virus can lead to loosening the intestinal epithelial barrier. On the other hand, supplementation of Lactobacillus or Saccharaomyces reduced infectious stress by ETEC. It was noted that major stressors altered the permeability of intestinal barriers and profiles of genes and proteins of pro-inflammatory cytokines and chemokines in mucosal system in pigs. However, it is not sufficient to fully explain the mechanism of the gut immune system in pigs under stress conditions. Correlation and interaction of gut and systemic immune system under major stressors should be better defined to overcome aforementioned obstacles.

• Journal of Microbiology and Biotechnology
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• 제28권11호
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• pp.1800-1805
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• 2018

Inflammatory bowel disease, including Crohn's disease and ulcerative colitis (UC), is a chronically relapsing inflammatory disorder of the gastrointestinal tract. Intestinal epithelial cells (IECs) constitute barrier surfaces and play a critical role in maintaining gut health. Dysregulated immune responses and destruction of IECs disrupt intestinal balance. Dextran sodium sulfate (DSS) is the most widely used chemical for inducing colitis in animals, and its treatment induces colonic inflammation, acute diarrhea, and shortening of the intestine, with clinical and histological similarity to human UC. Current treatments for this inflammatory disorder have poor tolerability and insufficient therapeutic efficacy, and thus, alternative therapeutic approaches are required. Recently, dietary supplements with probiotics have emerged as promising interventions by alleviating disturbances in the indigenous microflora in UC. Thus, we hypothesized that the probiotic Bifidobacterium animalis subsp. lactis strain BB12 could protect against the development of colitis in a DSS-induced mouse model of UC. In the present study, oral administration of BB12 markedly ameliorated DSS-induced colitis, accompanied by reduced tumor necrosis factor-${\alpha}$-mediated IEC apoptosis. These findings indicate that the probiotic strain BB12 can alleviate DSS-induced colitis and suggest a novel mechanism of communication between probiotic microorganisms and intestinal epithelia, which increases intestinal cell survival by modulating pro-apoptotic cytokine expression.

• BMB Reports
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• 제46권1호
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• pp.47-52
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• 2013

Intestinal epithelial cell (IEC) apoptosis induced by hypoxia compromise intestinal epithelium barrier function. Both Akt and Hsp90 have cytoprotective function. However, the specific role of Akt and $Hsp90{\beta}$ in IEC apoptosis induced by hypoxia has not been explored. We confirmed that hypoxia-induced apoptosis was reduced by $Hsp90{\beta}$ overexpression but enhanced by decreasing $Hsp90{\beta}$ expression. $Hsp90{\beta}$ overexpression enhanced BAD phosphorylation and thus reduced mitochondrial release of cytochrome C. Reducing $Hsp90{\beta}$ expression had opposite effects. The protective effect of $Hsp90{\beta}$ against apoptosis was negated by LY294002, an Akt inhibitor. Further study showed that Akt phosphorylation was enhanced by $Hsp90{\beta}$, which was not due to the activation of upstream PI3K and PDK1 but because of stabilization of pAkt via direct interaction between $Hsp90{\beta}$ and pAkt. These results demonstrate that $Hsp90{\beta}$ may play a significant role in protecting IECs from hypoxia-induced apoptosis via stabilizing pAkt to phosphorylate BAD and reduce cytochrome C release.

• Journal of Microbiology and Biotechnology
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• 제29권6호
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• pp.863-876
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• 2019

Farm animals such as piglets are often affected by environmental stress, which can disturb the gut ecosystem. Antibiotics were commonly used to prevent diarrhea in weaned piglets, but this was banned by the European Union due to the development of antibiotic resistance. However, the use of probiotics instead of antibiotics may reduce the risk posed by pathogenic microorganisms and reduce the incidence of gastrointestinal diseases. Therefore, this study was conducted to investigate the effects of Lactobacillus casei Zhang on the mechanical barrier and immune function of early-weaned piglets infected using Escherichia coli K88 based on histomorphology and immunology. Fourteen-day-old weaned piglets were divided into a control group and experimental groups that were fed L. casei Zhang and infected with E. coli K88 with or without prefeeding and/or postfeeding of L. casei Zhang. The L. casei Zhang dose used was $10^7CFU/g$ diet. Jejunum segments were obtained before histological, immunohistochemical, and western blot analyses were performed. In addition, the relative mRNA expression of toll receptors and cytokines was measured. Piglets fed L. casei Zhang showed significantly increased jejunum villus height, villus height-crypt depth ratio, muscle thickness, and expression of proliferating cell nuclear antigen and tight junction proteins ZO-1 and occludin. The use of L. casei Zhang effectively reduced intestinal inflammation after infection. We found that L. casei Zhang feeding prevented the jejunum damage induced by E. coli K88, suggesting that it may be a potential alternative to antibiotics for preventing diarrhea in early-weaned piglets.

• Asian-Australasian Journal of Animal Sciences
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• 제33권12호
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• pp.2008-2020
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• 2020

Objective: This study was conducted to investigate the effects of dietary corn resistant starch (RS) on the intestinal morphology and barrier functions of broilers. Methods: A total of 320 one-day-old broilers were randomly allocated to 5 dietary treatments: one normal corn-soybean (NC) diet, one corn-soybean-based diet supplementation with 20% corn starch (CS), and 3 corn-soybean-based diets supplementation with 4%, 8%, and 12% corn resistant starch (RS) (identified as 4% RS, 8% RS, and 12% RS, respectively). Each group had eight replicates with eight broilers per replicate. After 21 days feeding, one bird with a body weight (BW) close to the average BW of their replicate was selected and slaughtered. The samples of duodenum, jejunum, ileum, caecum digesta, and blood were collected. Results: Birds fed 4% RS, 8% RS and 12% RS diets showed lower feed intake, BW gain, jejunal villus height (VH), duodenal crypt depth (CD), jejunal VH/CD ratio, duodenal goblet cell density as well as mucin1 mRNA expressions compared to the NC group, but showed higher concentrations of cecal acetic acid and butyric acid, percentage of jejunal proliferating cell nuclear antigen-positive cells and delta like canonical Notch ligand 4 (Dll4), and hes family bHLH transcription factor 1 mRNA expressions. However, there were no differences on the plasma diamine oxidase activity and D-lactic acid concentration among all groups. Conclusion: These findings suggested that RS could suppress intestinal morphology and barrier functions by activating Notch pathway and inhibiting the development of goblet cells, resulting in decreased mucins and tight junction mRNA expression.

• Journal of Animal Science and Technology
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• 제63권2호
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• pp.211-247
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• 2021

Livestock species experience several stresses, particularly weaning, transportation, overproduction, crowding, temperature, and diseases in their life. Heat stress (HS) is one of the most stressors, which is encountered in livestock production systems throughout the world, especially in the tropical regions and is likely to be intensified due to global rise in environmental temperature. The gut has emerged as one of the major target organs affected by HS. The alpha- and beta-diversity of gut microbiota composition are altered due to heat exposure to animals with greater colonization of pathogenic microbiota groups. HS also induces several changes in the gut including damages of microstructures of the mucosal epithelia, increased oxidative insults, reduced immunity, and increased permeability of the gut to toxins and pathogens. Vulnerability of the intestinal barrier integrity leads to invasion of pathogenic microbes and translocation of antigens to the blood circulations, which ultimately may cause systematic inflammations and immune responses. Moreover, digestion of nutrients in the guts may be impaired due to reduced enzymatic activity in the digesta, reduced surface areas for absorption and injury to the mucosal structure and altered expressions of the nutrient transport proteins and genes. The systematic hormonal changes due to HS along with alterations in immune and inflammatory responses often cause reduced feed intake and production performance in livestock and poultry. The altered microbiome likely orchestrates to the hosts for various relevant biological phenomena occurring in the body, but the exact mechanisms how functional communications occur between the microbiota and HS responses are yet to be elucidated. This review aims to discuss the effects of HS on microbiota composition, mucosal structure, oxidant-antioxidant balance mechanism, immunity, and barrier integrity in the gut, and production performance of farm animals along with the dietary ameliorations of HS. Also, this review attempts to explain the mechanisms how these biological responses are affected by HS.

• 생명과학회지
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• 제26권9호
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• pp.1082-1087
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• 2016

본 연구에서는 염증성 사이토카인 IL-1α가 소장의 tight junction (TJ)의 integrity에 미치는 영향을 평가하고 항염증 효능이 있다고 알려진 curcumin (CCM)이 IL-1α에 의한 TJ 손상 예방효과를 알아보고자 Caco-2 세포 모델을 이용하여 실험하였다. Caco-2 세포 단층의 TJ integrity에 대한 IL-1α의 영향을 FITC-dextran flux와 transepithelial electrical resistance (TEER)를 측정하여 검증하였다. IL-1α를 100 ng/ml의 농도로 Caco-2 세포 단층의 상부에 24시간 동안 처리하였을 때 처리 2시간 이후 FITC-dextran의 flux가 유의적으로 증가하였고, IL-1α 처리시간에 비례하여 상승하였다. 또한 IL-1α의 처리는 TEER 값을 유의적으로 감소시켜 IL-1α에 의한 TJ 손상을 확인할 수 있었다. 반면 CCM의 전처리는 이러한 IL-1α에 의한 TJ 기능 저하를 거의 완전히 예방하는 것을 알 수 있었다. 이상의 결과로 염증성 사이토카인 IL-1α이 TJ의 integrity 조절에 부정적인 영향을 미치며 이는 강황에서 발견되는 CCM 전처리에 의해 효과적으로 억제될 수 있음을 보여준다. 본 연구 결과와 관련되어 TJ 구성단백질 발현 및 작용 기작에 대한 분자세포생물학적 연구와 in vivo 연구가 필요하다.

• Journal of Applied Biological Chemistry
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• 제64권4호
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• pp.383-389
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• 2021

비만은 숙주의 전신 염증 및 대사 기능 장애에 기여하는 장 상피 장벽 기능 저하와 관련이 있다. 한국의 전통 식품으로 식이섬유가 풍부한 콩 제품은 항염증 반응을 비롯한 다양한 생물학적 활성을 나타내어 왔으나 대장 건강에 대해서는 보고된 바가 없다. 본 연구에서는 고지방 식이(HFD)를 섭취한 비만 모델에서 콩(CSB)에 대한 장 건강 증진 효과를 조사하였다. SD 쥐에게 동물 실험 기간 동안 HFD 또는 10.6% CSB가 함유된 HFD (HFD + CSB)를 제공하였다. CSB의 섭취는 HFD로 유발된 체중과 지방 축적 증가를 현저하게 감소시켰다. 또한, CSB의 섭취는 대장 조직에서 HFD에 의해 감소된 밀착 결합 지표(ZO-1, Claudin-1 및 Occludin-1)의 mRNA 발현을 개선시켰다. 또한, 조직병리학적 평가에서도 CSB 섭취는 대장 조직에서 HFD에 의해 증가된 염증 세포 침윤과 대장 상피 조직 붕괴를 개선하는 것으로 나타났다. Genus 수준에서 HFD 섭취에 의해 Lactobacillus, Duncaniella, Alloprevotella 등 미생물 종의 abundance 차이는 확인되었으나, CSB 섭취로 인한 영향은 명확하게 나타나지 않았다. NMDS 분석에서 HFD 섭취에 의해 유의적인 장내미생물 생태 이동을 보여주었지만 CSB 섭취는 차이가 없었다. HFD와 CSB 간 유의적으로 차이가 나타나는 genera를 조사하기 위해 LEfSe를 수행한 결과, CSB는 Anaerotignum, Enterococcus, Clostridium sensu stricto 및 Escherichia/Shigella 속의 풍부함을 증가시킨 반면 Longicatena 및 Ligilactobacillus의 풍부함을 감소시켰다. 이러한 결과는 CSB 섭취는 긴밀한 접합 성분을 개선하여 HFD로 악화된 대장 건강을 개선하는 반면 장내미생물생태에 긍정적인 효과를 미치는지에 대해서는 명확하지 않았다.