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Developmental changes in cyclooxygenase mRNA expression in the gastric mucosa of rats
Takeshi Tomomasa1, Tetsushi Ogawa, Akio Hikima
1Department of Pediatrics, Gunma University School of Medicine, Maebashi, Japan. tomomasa@showa.gunma-u.ac.jp
Insights
Young rats exhibit enhanced gastric protection due to higher cyclooxygenase-2 (COX-2) mRNA levels. This finding highlights COX-2
Area of Science:
- Gastroenterology
- Developmental Biology
- Molecular Biology
Background:
- Newborn rat gastric mucosa is more vulnerable to damage but recovers faster than in older rats.
- Prostaglandin metabolism is investigated as a potential protective mechanism in developing rats.
Purpose of the Study:
- To investigate the role of cyclooxygenase (COX) mRNA expression in the developing rat gastric mucosa.
- To determine if prostaglandin metabolism influences age-related differences in gastric mucosal defense.
Main Methods:
- Quantitative real-time polymerase chain reaction (PCR) was used to analyze cyclooxygenase-1 (COX-1) and COX-2 mRNA expression in rat gastric mucosa across different ages.
- COX mRNA levels were standardized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression.
Main Results:
- COX-1 mRNA expression was lowest in 1-week-old rats and peaked at 4 weeks, with no significant increase following mucosal damage.
- COX-2 mRNA expression increased with age and was significantly upregulated by mucosal injury, particularly in 1-week-old rats.
- Lipopolysaccharide administration also elevated COX-2 mRNA levels in both 1- and 4-week-old rats.
Conclusions:
- The elevated COX-2 mRNA expression in the gastric mucosa of 1-week-old rats likely contributes to their enhanced gastric mucosal defense mechanisms.
- These findings suggest a critical role for COX-2 in the rapid recovery of gastric mucosa in young rats.
Background:
In newborn rats, gastric mucosa is more susceptible to various damaging agents and recovers from injury more quickly than in older animals. To determine whether metabolism of prostaglandins is responsible for this mucosal protective mechanism in developing rats, we studied cyclooxygenase (COX) mRNA expression in the mucosa using quantitative real-time polymerase chain reaction (PRC).
Methods:
Cyclooxygenase-1 and COX-2 mRNA was extracted from the gastric mucosa of rats of various ages and quantitatively analyzed using real-time PCR with dual-labeled fluorogenic probes. The copy numbers of cDNA for COX-1 and COX-2 were standardized to glyceraldehyde-3-phosphate dehydrogenase from the same sample.
Results:
Cyclooxygenase-1 mRNA expression was lowest in 1-week-old rats and highest in 4-week-old rats. Mucosal damage produced by 150 mmol/L HCl and 60% ethyl alcohol did not increase COX-1 mRNA expression in any age group. Cyclooxygenase-2 mRNA expression increased significantly with age. Mucosal injury increased COX-2 mRNA in each age group, especially in 1-week-old rats. Intraperitoneal lipopolysaccharide also increased COX-2 mRNA in both 1- and 4-week old rats.
Conclusion:
The high level of COX-2 mRNA expression in the gastric mucosa of 1-week-old rats may be responsible for the physiologic characteristics of gastric mucosal defenses in this age group.