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Effect of bile pigments on the compromised gut barrier function in a rat model of bile duct ligation.

Zhou K, Jiang M, Liu Y, Qu Y, Shi G, Yang X, Qin X, Wang X - PLoS ONE (2014)

Bottom Line: Trypsin and chymotrypsin of the gut were also measured to determine how these digestive proteases may relate to the observed effects of bile pigments.Free bilirubin but not bilirubin ditaurate or biliverdin showed significant inhibitions on trypsin and chymotrypsin as well as alleviated changes of histological and biochemical parameters related to gut barrier disruption.Bile may protect the gut from damage through inhibiting digestive proteases like trypsin and chymotrypsin by free bilirubin.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Heilongjiang Provincial Science and Technology Innovation Team in Higher Education Institutes for Infection and Immunity, Harbin Medical University, Harbin, China.

ABSTRACT

Background: Studies have shown that the absence of bile in the gut lumen, either by bile duct ligation or bile diversion, induces mucosal injury. However, the mechanism remains elusive. In this study, the role of bile pigments in gut barrier function was investigated in a rat model of bile duct ligation.

Methods: Male Sprague Dawley (SD) rats were used in this study. After ligation of bile duct, the animals were administrated with free bilirubin, bilirubin ditaurate, or biliverdin by intragastric gavage. 1, 2, or 3 days later, the animals were sacrificed and the damage of mucosa was assessed by histological staining as well as biochemical parameters such as changes of diamine oxidase (DAO) and D-lactate (D-Lac) in the blood. Trypsin and chymotrypsin of the gut were also measured to determine how these digestive proteases may relate to the observed effects of bile pigments.

Results: Bile duct ligation (BDL) caused significant increases in gut trypsin and chymotrypsin along with damage of the mucosa as demonstrated by the histological findings under microscope, the reduced expression of tight junction molecules like occludin, and significant changes in DAO and D-lac in the blood. Free bilirubin but not bilirubin ditaurate or biliverdin showed significant inhibitions on trypsin and chymotrypsin as well as alleviated changes of histological and biochemical parameters related to gut barrier disruption.

Conclusion: Bile may protect the gut from damage through inhibiting digestive proteases like trypsin and chymotrypsin by free bilirubin.

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Related in: MedlinePlus

Markers and the histopathologic changes of gut barrier disruption.After BDL, the serum concentrations of DAO (A) and D-Lac (B) were assayed by spectrophotometric assay. Protein expression of occludin (65 kDa) was analyzed by Western blot (C). Occludin bands were normalized by actin and expressed as relative to control (D). Intestinal slices were stained with HE staining and analyzed by inverted fluorescence microscope, middle small intestine were blindly assessed for the degree of histopathology (E), all photos were captured at ×40 magnification (F). Results are mean ± SD from at least three independent experiments. ***p<0.001 vs. respective control.
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pone-0098905-g002: Markers and the histopathologic changes of gut barrier disruption.After BDL, the serum concentrations of DAO (A) and D-Lac (B) were assayed by spectrophotometric assay. Protein expression of occludin (65 kDa) was analyzed by Western blot (C). Occludin bands were normalized by actin and expressed as relative to control (D). Intestinal slices were stained with HE staining and analyzed by inverted fluorescence microscope, middle small intestine were blindly assessed for the degree of histopathology (E), all photos were captured at ×40 magnification (F). Results are mean ± SD from at least three independent experiments. ***p<0.001 vs. respective control.

Mentions: Next, we evaluated the effects of BDL on DAO, D-Lac levels in serum as well as the barrier protein expression of occludin in epithelial tight junction of intestinal mucosa, as these proteins are important indicators of intestinal permeability and integrity [21]–[23]. The results are reported in Figure 2.


Effect of bile pigments on the compromised gut barrier function in a rat model of bile duct ligation.

Zhou K, Jiang M, Liu Y, Qu Y, Shi G, Yang X, Qin X, Wang X - PLoS ONE (2014)

Markers and the histopathologic changes of gut barrier disruption.After BDL, the serum concentrations of DAO (A) and D-Lac (B) were assayed by spectrophotometric assay. Protein expression of occludin (65 kDa) was analyzed by Western blot (C). Occludin bands were normalized by actin and expressed as relative to control (D). Intestinal slices were stained with HE staining and analyzed by inverted fluorescence microscope, middle small intestine were blindly assessed for the degree of histopathology (E), all photos were captured at ×40 magnification (F). Results are mean ± SD from at least three independent experiments. ***p<0.001 vs. respective control.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4044053&req=5

pone-0098905-g002: Markers and the histopathologic changes of gut barrier disruption.After BDL, the serum concentrations of DAO (A) and D-Lac (B) were assayed by spectrophotometric assay. Protein expression of occludin (65 kDa) was analyzed by Western blot (C). Occludin bands were normalized by actin and expressed as relative to control (D). Intestinal slices were stained with HE staining and analyzed by inverted fluorescence microscope, middle small intestine were blindly assessed for the degree of histopathology (E), all photos were captured at ×40 magnification (F). Results are mean ± SD from at least three independent experiments. ***p<0.001 vs. respective control.
Mentions: Next, we evaluated the effects of BDL on DAO, D-Lac levels in serum as well as the barrier protein expression of occludin in epithelial tight junction of intestinal mucosa, as these proteins are important indicators of intestinal permeability and integrity [21]–[23]. The results are reported in Figure 2.

Bottom Line: Trypsin and chymotrypsin of the gut were also measured to determine how these digestive proteases may relate to the observed effects of bile pigments.Free bilirubin but not bilirubin ditaurate or biliverdin showed significant inhibitions on trypsin and chymotrypsin as well as alleviated changes of histological and biochemical parameters related to gut barrier disruption.Bile may protect the gut from damage through inhibiting digestive proteases like trypsin and chymotrypsin by free bilirubin.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Heilongjiang Provincial Science and Technology Innovation Team in Higher Education Institutes for Infection and Immunity, Harbin Medical University, Harbin, China.

ABSTRACT

Background: Studies have shown that the absence of bile in the gut lumen, either by bile duct ligation or bile diversion, induces mucosal injury. However, the mechanism remains elusive. In this study, the role of bile pigments in gut barrier function was investigated in a rat model of bile duct ligation.

Methods: Male Sprague Dawley (SD) rats were used in this study. After ligation of bile duct, the animals were administrated with free bilirubin, bilirubin ditaurate, or biliverdin by intragastric gavage. 1, 2, or 3 days later, the animals were sacrificed and the damage of mucosa was assessed by histological staining as well as biochemical parameters such as changes of diamine oxidase (DAO) and D-lactate (D-Lac) in the blood. Trypsin and chymotrypsin of the gut were also measured to determine how these digestive proteases may relate to the observed effects of bile pigments.

Results: Bile duct ligation (BDL) caused significant increases in gut trypsin and chymotrypsin along with damage of the mucosa as demonstrated by the histological findings under microscope, the reduced expression of tight junction molecules like occludin, and significant changes in DAO and D-lac in the blood. Free bilirubin but not bilirubin ditaurate or biliverdin showed significant inhibitions on trypsin and chymotrypsin as well as alleviated changes of histological and biochemical parameters related to gut barrier disruption.

Conclusion: Bile may protect the gut from damage through inhibiting digestive proteases like trypsin and chymotrypsin by free bilirubin.

Show MeSH
Related in: MedlinePlus