Abstract
Purpose. Using two animal models to determine which isoform of cyclooxygenase (COX), constitutive COX-1 or inducible COX-2, is involved in the progression of anterior ocular inflammation. Methods. Lambda-carrageenan (500 μg/eye) or bacterial lipopolysaccharide (LPS; 3 μg/eye) was injected into rat conjunctiva to induce conjunctivitis. Vascular permeability in inflamed conjunctiva was measured by uptake of systemic Evans blue. Changes in mRNA for COX-1 and COX-2 in conjunctiva were detected by RT-PCR. Changes in COX-2 protein were detected by immunoblotting after immunoprecipitation. To assess involvement of COX-2 in carrageenan- and LPS-induced conjunctivitis, NS-398 (a selective COX-2 inhibitor) or indomethacin (non-selective COX inhibitor) was topically administrated at 15 and 30 minutes before inflammatory stimulator-injection. Results. In the carrageenan-injected model, the dye content of conjunctiva (12.4 ± 2.8 mg/eye) was significantly increased 4 hours after injection compared to saline-injected control rats (3.7 ± 1.1 mg/eye). mRNA for COX-2 was significantly increased by 2 hours and gradually increased until 24 hours; COX-1 mRNA did not show major changes until 24 hours after injection. COX-2 protein was markedly elevated 4 hours after injection of carrageenan. COX-2 protein levels were well correlated with increased mRNA levels. In the LPS-injected model, the dye content of conjunctiva (5.8 ± 1.2 mg/eye) was significantly increased 4 hours after injection compared to saline-injected control rats (3.1 ± 0.6 mg/eye). Expression of COX-2 mRNA was increased 1 hour after injection, peaked at 2 hours, and decreased at 4 hours. mRNA for COX-1 did not change by 24 hours. COX-2 protein increased 2 hours after injection of LPS. COX-2 protein levels were well correlated with increased mRNA. Topical administration of 1% NS-398 exhibited strong inhibition of dye-leakage into conjunctiva 4 hours after injection of carrageenan or LPS, since 59% or 83% of dye-uptake were inhibited, respectively. 1% of indomethacin eye drops showed only a minimal effect. Conclusions. These results suggest that the mechanism for anterior ocular inflammation may be due to up-regulation of COX-2.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 27-34 |
| Number of pages | 8 |
| Journal | Current Eye Research |
| Volume | 29 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jul 2004 |
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Keywords
- Animal model
- Carrageenan
- Conjunctivitis
- Cyclooxygenase inhibitor
- Lipopolysaccharide
ASJC Scopus subject areas
- Ophthalmology
- Sensory Systems
Cite this
Involvement of cyclooxygenase-2 in rat models of conjunctivitis. / Oka, Takayuki; Shearer, Thomas (Tom); Azuma, Mitsuyoshi.
In: Current Eye Research, Vol. 29, No. 1, 07.2004, p. 27-34.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Involvement of cyclooxygenase-2 in rat models of conjunctivitis
AU - Oka, Takayuki
AU - Shearer, Thomas (Tom)
AU - Azuma, Mitsuyoshi
PY - 2004/7
Y1 - 2004/7
N2 - Purpose. Using two animal models to determine which isoform of cyclooxygenase (COX), constitutive COX-1 or inducible COX-2, is involved in the progression of anterior ocular inflammation. Methods. Lambda-carrageenan (500 μg/eye) or bacterial lipopolysaccharide (LPS; 3 μg/eye) was injected into rat conjunctiva to induce conjunctivitis. Vascular permeability in inflamed conjunctiva was measured by uptake of systemic Evans blue. Changes in mRNA for COX-1 and COX-2 in conjunctiva were detected by RT-PCR. Changes in COX-2 protein were detected by immunoblotting after immunoprecipitation. To assess involvement of COX-2 in carrageenan- and LPS-induced conjunctivitis, NS-398 (a selective COX-2 inhibitor) or indomethacin (non-selective COX inhibitor) was topically administrated at 15 and 30 minutes before inflammatory stimulator-injection. Results. In the carrageenan-injected model, the dye content of conjunctiva (12.4 ± 2.8 mg/eye) was significantly increased 4 hours after injection compared to saline-injected control rats (3.7 ± 1.1 mg/eye). mRNA for COX-2 was significantly increased by 2 hours and gradually increased until 24 hours; COX-1 mRNA did not show major changes until 24 hours after injection. COX-2 protein was markedly elevated 4 hours after injection of carrageenan. COX-2 protein levels were well correlated with increased mRNA levels. In the LPS-injected model, the dye content of conjunctiva (5.8 ± 1.2 mg/eye) was significantly increased 4 hours after injection compared to saline-injected control rats (3.1 ± 0.6 mg/eye). Expression of COX-2 mRNA was increased 1 hour after injection, peaked at 2 hours, and decreased at 4 hours. mRNA for COX-1 did not change by 24 hours. COX-2 protein increased 2 hours after injection of LPS. COX-2 protein levels were well correlated with increased mRNA. Topical administration of 1% NS-398 exhibited strong inhibition of dye-leakage into conjunctiva 4 hours after injection of carrageenan or LPS, since 59% or 83% of dye-uptake were inhibited, respectively. 1% of indomethacin eye drops showed only a minimal effect. Conclusions. These results suggest that the mechanism for anterior ocular inflammation may be due to up-regulation of COX-2.
AB - Purpose. Using two animal models to determine which isoform of cyclooxygenase (COX), constitutive COX-1 or inducible COX-2, is involved in the progression of anterior ocular inflammation. Methods. Lambda-carrageenan (500 μg/eye) or bacterial lipopolysaccharide (LPS; 3 μg/eye) was injected into rat conjunctiva to induce conjunctivitis. Vascular permeability in inflamed conjunctiva was measured by uptake of systemic Evans blue. Changes in mRNA for COX-1 and COX-2 in conjunctiva were detected by RT-PCR. Changes in COX-2 protein were detected by immunoblotting after immunoprecipitation. To assess involvement of COX-2 in carrageenan- and LPS-induced conjunctivitis, NS-398 (a selective COX-2 inhibitor) or indomethacin (non-selective COX inhibitor) was topically administrated at 15 and 30 minutes before inflammatory stimulator-injection. Results. In the carrageenan-injected model, the dye content of conjunctiva (12.4 ± 2.8 mg/eye) was significantly increased 4 hours after injection compared to saline-injected control rats (3.7 ± 1.1 mg/eye). mRNA for COX-2 was significantly increased by 2 hours and gradually increased until 24 hours; COX-1 mRNA did not show major changes until 24 hours after injection. COX-2 protein was markedly elevated 4 hours after injection of carrageenan. COX-2 protein levels were well correlated with increased mRNA levels. In the LPS-injected model, the dye content of conjunctiva (5.8 ± 1.2 mg/eye) was significantly increased 4 hours after injection compared to saline-injected control rats (3.1 ± 0.6 mg/eye). Expression of COX-2 mRNA was increased 1 hour after injection, peaked at 2 hours, and decreased at 4 hours. mRNA for COX-1 did not change by 24 hours. COX-2 protein increased 2 hours after injection of LPS. COX-2 protein levels were well correlated with increased mRNA. Topical administration of 1% NS-398 exhibited strong inhibition of dye-leakage into conjunctiva 4 hours after injection of carrageenan or LPS, since 59% or 83% of dye-uptake were inhibited, respectively. 1% of indomethacin eye drops showed only a minimal effect. Conclusions. These results suggest that the mechanism for anterior ocular inflammation may be due to up-regulation of COX-2.
KW - Animal model
KW - Carrageenan
KW - Conjunctivitis
KW - Cyclooxygenase inhibitor
KW - Lipopolysaccharide
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U2 - 10.1080/02713680490513164
DO - 10.1080/02713680490513164
M3 - Article
VL - 29
SP - 27
EP - 34
JO - Current Eye Research
JF - Current Eye Research
SN - 0271-3683
IS - 1
ER -