The Expressions of iNOS and COX-2 in the Paraffin-embedded Skin Lesions of the Patients with Leprosy

Kim, Myung Hwa; Choi, Yoo Won; Choi, Hae Young; Myung, Ki Bum

Abstract

BACKGROUND: Nitric oxide(NO) produced by activated macrophages through the action of iNOS is the key molecule in the killing mycobacterium. Prostaglandins produced by the action of COX-2, also, are the important mediators of inflammation and other pathophysiologic process. A complex relationship is emerging with regard to "cross-talk" between the NO and COX-2 pathways.
OBJECTIVE
The purposes of this study were to investigate the expression of iNOS and COX-2 across the spectrum of leprosy in the paraffin-embedded skin lesions, to demonstrate the interaction between iNOS and COX-2 expression, and to demonstrate the differences in the cell types expressing the iNOS or COX-2. METHOD: In the paraffin-embedded skin lesions of 30 new cases of leprosy(TT, n=4; BT, n=4; BL, n=7; LL, n=15), iNOS and COX-2 expression were detected by using immunohistochemical staining.
RESULTS
iNOS expression was 2.0-55.8%(mean 15.9%) and the level of expression of iNOS in TT(31.2%) and BT(32.6%) lesions was significantly higher than that of BL(11.1%) and LL(8.6%) lesions(p<0.05). COX-2 expression was 3.6-74.5%(mean 27.1%) and the level of expression of COX-2 in TT(59.2%) lesions was significantly higher than that of BT, BL and LL lesions(p<0.05). There was positive correlation between iNOS and COX-2 expression, that is, the lesions which expressed high level of iNOS also expressed COX-2 highly. The correlation was statistically significant(r=0.535, p<0.05). The overall level of COX-2 expression(27.1%) was higher than that of iNOS expression(15.9%), and when compared the expression of them across the spectrum of leprosy, COX-2 expressed higher than iNOS in TT and LL lesions.
CONCLUSION
Both iNOS and COX-2 were expressed in all types of leprosy skin lesions and the level of iNOS expression in TT and BT lesions was significantly higher than that of BL and LL lesions. The level of expression of COX-2 in TT lesions was significantly higher than that of BT, BL and LL lesions. These results suggest that iNOS and COX-2 have important roles in anti-mycobacterial activities in leprosy lesions. The positive correlation between iNOS and COX-2 expression suggests that NO and COX-2 might interact synergistically or additively rather than suppress each other.