Bacterial Endotoxin Induces Oxidative Stress and Reduces Milk Protein Expression and Hypoxia in the Mouse Mammary Gland
The aim of this study was to investigate the mechanisms underlying the reduced milk production during mastitis. We hypothesized that bacterial endotoxin induces hypoxia, oxidative stress, and cell apoptosis while inhibiting milk gene expression in the mammary gland. To test this hypothesis, the left...
Main Authors: | , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Hindawi Limited
2020-01-01
|
Series: | Oxidative Medicine and Cellular Longevity |
Online Access: | http://dx.doi.org/10.1155/2020/3894309 |
id |
doaj-be6fc9d68c3b494aa46a1143912c7cfa |
---|---|
record_format |
Article |
spelling |
doaj-be6fc9d68c3b494aa46a1143912c7cfa2020-11-25T02:28:15ZengHindawi LimitedOxidative Medicine and Cellular Longevity1942-09001942-09942020-01-01202010.1155/2020/38943093894309Bacterial Endotoxin Induces Oxidative Stress and Reduces Milk Protein Expression and Hypoxia in the Mouse Mammary GlandAlexander Jonathan Spitzer0Qing Tian1Ratan K. Choudhary2Feng-Qi Zhao3Department of Animal and Veterinary Sciences, University of Vermont, 570 Main Street, Burlington, VT 05452, USADepartment of Animal and Veterinary Sciences, University of Vermont, 570 Main Street, Burlington, VT 05452, USADepartment of Animal and Veterinary Sciences, University of Vermont, 570 Main Street, Burlington, VT 05452, USADepartment of Animal and Veterinary Sciences, University of Vermont, 570 Main Street, Burlington, VT 05452, USAThe aim of this study was to investigate the mechanisms underlying the reduced milk production during mastitis. We hypothesized that bacterial endotoxin induces hypoxia, oxidative stress, and cell apoptosis while inhibiting milk gene expression in the mammary gland. To test this hypothesis, the left and right sides of the 4th pair of mouse mammary glands were alternatively injected with either lipopolysaccharide (LPS, E. coli 055: B5, 100 μL of 0.2 mg/mL) or sterile PBS through the teat meatus 3 days postpartum. At 10.5 and 22.5 h postinjection, pimonidazole HCl, a hypoxyprobe, was injected intraperitoneally. At 12 or 24 h after the LPS injection, the 4th glands were individually collected (n=8) and analyzed. LPS treatment induced mammary inflammation at both 12 and 24 h but promoted cell apoptosis only at 12 h. Consistently, H2O2 content was increased at 12 h (P<0.01), but dropped dramatically at 24 h (P<0.01) in the LPS-treated gland. Nevertheless, the total antioxidative capacity in tissue tended to be decreased by LPS at both 12 and 24 h (P=0.07 and 0.06, respectively). In agreement with these findings, LPS increased or tended to increase the mRNA expression of antioxidative genes Nqo1 at 12 h (P=0.05) and SLC7A11 at 24 h (P=0.08). In addition, LPS inhibited mammary expression of Csn2 and Lalba across time and protein expression of Csn1s1 at 24 h (P<0.05). Furthermore, hypoxyprobe staining intensity was greater in the alveoli of the PBS-treated gland than the LPS-treated gland at both 12 and 24 h, demonstrating a rise in oxygen tension by LPS treatment. In summary, our observations indicated that while intramammary LPS challenge incurs inflammation, it induces oxidative stress, increases cell apoptosis and oxygen tension, and differentially inhibits the milk protein expression in the mammary gland.http://dx.doi.org/10.1155/2020/3894309 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Alexander Jonathan Spitzer Qing Tian Ratan K. Choudhary Feng-Qi Zhao |
spellingShingle |
Alexander Jonathan Spitzer Qing Tian Ratan K. Choudhary Feng-Qi Zhao Bacterial Endotoxin Induces Oxidative Stress and Reduces Milk Protein Expression and Hypoxia in the Mouse Mammary Gland Oxidative Medicine and Cellular Longevity |
author_facet |
Alexander Jonathan Spitzer Qing Tian Ratan K. Choudhary Feng-Qi Zhao |
author_sort |
Alexander Jonathan Spitzer |
title |
Bacterial Endotoxin Induces Oxidative Stress and Reduces Milk Protein Expression and Hypoxia in the Mouse Mammary Gland |
title_short |
Bacterial Endotoxin Induces Oxidative Stress and Reduces Milk Protein Expression and Hypoxia in the Mouse Mammary Gland |
title_full |
Bacterial Endotoxin Induces Oxidative Stress and Reduces Milk Protein Expression and Hypoxia in the Mouse Mammary Gland |
title_fullStr |
Bacterial Endotoxin Induces Oxidative Stress and Reduces Milk Protein Expression and Hypoxia in the Mouse Mammary Gland |
title_full_unstemmed |
Bacterial Endotoxin Induces Oxidative Stress and Reduces Milk Protein Expression and Hypoxia in the Mouse Mammary Gland |
title_sort |
bacterial endotoxin induces oxidative stress and reduces milk protein expression and hypoxia in the mouse mammary gland |
publisher |
Hindawi Limited |
series |
Oxidative Medicine and Cellular Longevity |
issn |
1942-0900 1942-0994 |
publishDate |
2020-01-01 |
description |
The aim of this study was to investigate the mechanisms underlying the reduced milk production during mastitis. We hypothesized that bacterial endotoxin induces hypoxia, oxidative stress, and cell apoptosis while inhibiting milk gene expression in the mammary gland. To test this hypothesis, the left and right sides of the 4th pair of mouse mammary glands were alternatively injected with either lipopolysaccharide (LPS, E. coli 055: B5, 100 μL of 0.2 mg/mL) or sterile PBS through the teat meatus 3 days postpartum. At 10.5 and 22.5 h postinjection, pimonidazole HCl, a hypoxyprobe, was injected intraperitoneally. At 12 or 24 h after the LPS injection, the 4th glands were individually collected (n=8) and analyzed. LPS treatment induced mammary inflammation at both 12 and 24 h but promoted cell apoptosis only at 12 h. Consistently, H2O2 content was increased at 12 h (P<0.01), but dropped dramatically at 24 h (P<0.01) in the LPS-treated gland. Nevertheless, the total antioxidative capacity in tissue tended to be decreased by LPS at both 12 and 24 h (P=0.07 and 0.06, respectively). In agreement with these findings, LPS increased or tended to increase the mRNA expression of antioxidative genes Nqo1 at 12 h (P=0.05) and SLC7A11 at 24 h (P=0.08). In addition, LPS inhibited mammary expression of Csn2 and Lalba across time and protein expression of Csn1s1 at 24 h (P<0.05). Furthermore, hypoxyprobe staining intensity was greater in the alveoli of the PBS-treated gland than the LPS-treated gland at both 12 and 24 h, demonstrating a rise in oxygen tension by LPS treatment. In summary, our observations indicated that while intramammary LPS challenge incurs inflammation, it induces oxidative stress, increases cell apoptosis and oxygen tension, and differentially inhibits the milk protein expression in the mammary gland. |
url |
http://dx.doi.org/10.1155/2020/3894309 |
work_keys_str_mv |
AT alexanderjonathanspitzer bacterialendotoxininducesoxidativestressandreducesmilkproteinexpressionandhypoxiainthemousemammarygland AT qingtian bacterialendotoxininducesoxidativestressandreducesmilkproteinexpressionandhypoxiainthemousemammarygland AT ratankchoudhary bacterialendotoxininducesoxidativestressandreducesmilkproteinexpressionandhypoxiainthemousemammarygland AT fengqizhao bacterialendotoxininducesoxidativestressandreducesmilkproteinexpressionandhypoxiainthemousemammarygland |
_version_ |
1715478029956808704 |