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Hepatic inducible nitric oxide synthase expression increases upon exposure to hypergravity.

Kim HS, Jung YY, Do SI - Braz. J. Med. Biol. Res. (2014)

Bottom Line: At 0 and 1 h, weak cytoplasmic iNOS immunoreactivity was found in some hepatocytes surrounding terminal hepatic venules.The majority of positively stained cells showed a strong intensity of iNOS expression.These results suggest that exposure to hypergravity significantly upregulates iNOS at both transcriptional and translational levels.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.

ABSTRACT
Stimulation by a number of conditions, including infection, cytokines, mechanical injury, and hypoxia, can upregulate inducible nitric oxide synthase (iNOS) in hepatocytes. We observed that exposure to hypergravity significantly upregulated the transcription of the hepatic iNOS gene. The aim of this study was to confirm our preliminary data, and to further investigate the distribution of the iNOS protein in the livers of mice exposed to hypergravity. ICR mice were exposed to +3 Gz for 1 h. We investigated the time course of change in the iNOS expression. Hepatic iNOS mRNA expression progressively increased in centrifuged mice from 0 to 12 h, and then decreased rapidly by 18 h. iNOS mRNA levels in the livers of centrifuged mice was significantly higher at 3, 6, and 12 h than in uncentrifuged control mice. The pattern of iNOS protein expression paralleled that of the mRNA expression. At 0 and 1 h, weak cytoplasmic iNOS immunoreactivity was found in some hepatocytes surrounding terminal hepatic venules. It was noted that at 6 h there was an increase in the number of perivenular hepatocytes with moderate to strong cytoplasmic immunoreactivity. The number of iNOS-positive hepatocytes was maximally increased at 12 h. The majority of positively stained cells showed a strong intensity of iNOS expression. The expression levels of iNOS mRNA and protein were significantly increased in the livers of mice exposed to hypergravity. These results suggest that exposure to hypergravity significantly upregulates iNOS at both transcriptional and translational levels.

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Related in: MedlinePlus

Effect of hypergravity exposure on inducible nitric oxide synthase (iNOS)mRNA expression in the livers of mice. Quantitative real-time RT-PCR analysisof iNOS mRNA was performed. Data are reported as the means±SE of 3 independentexperiments in each group. The 3, 6, and 12 h groups displayed significantlyhigher iNOS mRNA levels in the liver than the control group (*P<0.01 and**P<0.001, Student t-test). In contrast, in the 18 and 24 hgroups, hepatic iNOS mRNA was undetectable.
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f01: Effect of hypergravity exposure on inducible nitric oxide synthase (iNOS)mRNA expression in the livers of mice. Quantitative real-time RT-PCR analysisof iNOS mRNA was performed. Data are reported as the means±SE of 3 independentexperiments in each group. The 3, 6, and 12 h groups displayed significantlyhigher iNOS mRNA levels in the liver than the control group (*P<0.01 and**P<0.001, Student t-test). In contrast, in the 18 and 24 hgroups, hepatic iNOS mRNA was undetectable.

Mentions: None of the animals displayed remarkable changes in behavior during or aftercentrifugation. As shown in Figure 1, hepaticiNOS mRNA was almost undetectable in the control group. However, exposure tohypergravity upregulated the transcription of hepatic iNOS gene in the centrifugedgroups. In the livers of the 0 and 1 h groups, iNOS mRNA was present, albeit at lowlevels, and it did not reach statistical significance. The 3 h group showed a4.8-fold increase in the amount of hepatic iNOS mRNA, which was significantlydifferent from that of the 0 h group (P=0.002). Exposure to hypergravity for 6 hinduced a further increase in iNOS mRNA. Compared to the 0 h group, the 6 h groupshowed a 20.8-fold increase in the amount of iNOS mRNA (P<0.001). Maximalexpression of hepatic iNOS mRNA was observed at 12 h. The livers of the 12 h groupdemonstrated a 23.6-fold increase in iNOS mRNA level compared with that of the 0 hgroup (P<0.001). In contrast, at 18 and 24 h, hepatic iNOS mRNA expression wasundetectable.


Hepatic inducible nitric oxide synthase expression increases upon exposure to hypergravity.

Kim HS, Jung YY, Do SI - Braz. J. Med. Biol. Res. (2014)

Effect of hypergravity exposure on inducible nitric oxide synthase (iNOS)mRNA expression in the livers of mice. Quantitative real-time RT-PCR analysisof iNOS mRNA was performed. Data are reported as the means±SE of 3 independentexperiments in each group. The 3, 6, and 12 h groups displayed significantlyhigher iNOS mRNA levels in the liver than the control group (*P<0.01 and**P<0.001, Student t-test). In contrast, in the 18 and 24 hgroups, hepatic iNOS mRNA was undetectable.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230283&req=5

f01: Effect of hypergravity exposure on inducible nitric oxide synthase (iNOS)mRNA expression in the livers of mice. Quantitative real-time RT-PCR analysisof iNOS mRNA was performed. Data are reported as the means±SE of 3 independentexperiments in each group. The 3, 6, and 12 h groups displayed significantlyhigher iNOS mRNA levels in the liver than the control group (*P<0.01 and**P<0.001, Student t-test). In contrast, in the 18 and 24 hgroups, hepatic iNOS mRNA was undetectable.
Mentions: None of the animals displayed remarkable changes in behavior during or aftercentrifugation. As shown in Figure 1, hepaticiNOS mRNA was almost undetectable in the control group. However, exposure tohypergravity upregulated the transcription of hepatic iNOS gene in the centrifugedgroups. In the livers of the 0 and 1 h groups, iNOS mRNA was present, albeit at lowlevels, and it did not reach statistical significance. The 3 h group showed a4.8-fold increase in the amount of hepatic iNOS mRNA, which was significantlydifferent from that of the 0 h group (P=0.002). Exposure to hypergravity for 6 hinduced a further increase in iNOS mRNA. Compared to the 0 h group, the 6 h groupshowed a 20.8-fold increase in the amount of iNOS mRNA (P<0.001). Maximalexpression of hepatic iNOS mRNA was observed at 12 h. The livers of the 12 h groupdemonstrated a 23.6-fold increase in iNOS mRNA level compared with that of the 0 hgroup (P<0.001). In contrast, at 18 and 24 h, hepatic iNOS mRNA expression wasundetectable.

Bottom Line: At 0 and 1 h, weak cytoplasmic iNOS immunoreactivity was found in some hepatocytes surrounding terminal hepatic venules.The majority of positively stained cells showed a strong intensity of iNOS expression.These results suggest that exposure to hypergravity significantly upregulates iNOS at both transcriptional and translational levels.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.

ABSTRACT
Stimulation by a number of conditions, including infection, cytokines, mechanical injury, and hypoxia, can upregulate inducible nitric oxide synthase (iNOS) in hepatocytes. We observed that exposure to hypergravity significantly upregulated the transcription of the hepatic iNOS gene. The aim of this study was to confirm our preliminary data, and to further investigate the distribution of the iNOS protein in the livers of mice exposed to hypergravity. ICR mice were exposed to +3 Gz for 1 h. We investigated the time course of change in the iNOS expression. Hepatic iNOS mRNA expression progressively increased in centrifuged mice from 0 to 12 h, and then decreased rapidly by 18 h. iNOS mRNA levels in the livers of centrifuged mice was significantly higher at 3, 6, and 12 h than in uncentrifuged control mice. The pattern of iNOS protein expression paralleled that of the mRNA expression. At 0 and 1 h, weak cytoplasmic iNOS immunoreactivity was found in some hepatocytes surrounding terminal hepatic venules. It was noted that at 6 h there was an increase in the number of perivenular hepatocytes with moderate to strong cytoplasmic immunoreactivity. The number of iNOS-positive hepatocytes was maximally increased at 12 h. The majority of positively stained cells showed a strong intensity of iNOS expression. The expression levels of iNOS mRNA and protein were significantly increased in the livers of mice exposed to hypergravity. These results suggest that exposure to hypergravity significantly upregulates iNOS at both transcriptional and translational levels.

Show MeSH
Related in: MedlinePlus