Abstract
The possible participation of cyclooxygenase (COX)-2 in angiogenesis in granulation tissue was analyzed using an air pouch-type carrageenin-induced inflammation model in rats. Injection of carrageenin solution into an air pouch induced gradual increases in the pouch fluid volume and granulation tissue weight as well as angiogenesis in granulation tissue. NS-398 (10–100 μg) inhibited all of these parameters in a dose-dependent manner. NS-398 (100 μg), indomethacin (100 μg), and dexamethasone (10 μg) markedly reduced prostaglandin (PG) E2 levels in the pouch fluid at day 6. NS-398 and indomethacin did not affect protein levels of COX-1 and COX-2 but dexamethasone significantly reduced the level of COX-2 in granulation tissue at day 6. Protein levels of vascular endothelial growth factor (VEGF) in granulation tissue and in the pouch fluid were higher at day 6 than at day 3, and the levels were decreased by treatment with NS-398 (10–100 μg) in a dose-dependent manner. The inhibitory effects of NS-398 (100 μg) were almost the same as those of indomethacin (100 μg). Dexamethasone (10 μg) also reduced VEGF protein levels in granulation tissue at day 6. To clarify the role of PGE2 in VEGF production, minced granulation tissue obtained 3 days after carrageenin injection from the indomethacin-treated rats was incubated in the presence of various concentrations of PGE2. It was shown that VEGF mRNA and protein levels in the minced granulation tissue were increased by PGE2 in a concentration-dependent manner. These findings suggest that COX-2-derived PGE2 plays a significant role in angiogenesis in the carrageenin-induced granulation tissue through VEGF formation.
Footnotes
-
Send reprint requests to: Kazuo Ohuchi, Ph.D., Prof., Laboratory of Pathophysiological Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, Japan. E-mail:ohuchi-k{at}mail.pharm.tohoku.ac.jp
-
↵1 This study was supported in part by a Grant-in-Aid for Exploratory Research (11877381) and Scientific Research (11470481) from the Ministry of Education, Science, Sports and Culture of Japan.
- Abbreviations:
- COX
- cyclooxygenase
- PG
- prostaglandin
- VEGF
- vascular endothelial growth factor
- EMEM
- Eagle's minimal essential medium
- RT-PCR
- reverse transcription-polymerase chain reaction
- bp
- base pair
- GAPDH
- glyceraldehyde 3-phosphate dehydrogenase
- Received May 19, 2000.
- Accepted August 4, 2000.
- The American Society for Pharmacology and Experimental Therapeutics
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|