The role of nitric oxide in resistance to P. aeruginosa ocular infection.
OBJECTIVE
This study determined the role of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) in the resistance response of BALB/c mice to P. aeruginosa-induced keratitis.


METHODS
RT-PCR, nitrite detection, iNOS inhibition, ELISA, and immunohistochemistry were used.


RESULTS
Early after infection, iNOS mRNA expression and nitrite levels in cornea were elevated compared to levels in the uninfected cornea. Treatment with aminoguanidine sulfate (AG), an inhibitor of iNOS, resulted in extensive corneal destruction, reduced nitrite levels, and reduced nitrotyrosine staining. Infected mice also had increased bacterial burden and elevated levels of MIP-1alpha, IL-1beta, and MIP-2 in the cornea. Dual-labeling immunohistochemistry established the macrophage as the major source of iNOS in the infected cornea.


CONCLUSIONS
These data provide evidence that iNOS is constitutively expressed in the BALB/c cornea; that iNOS-derived NO is required for bacterial killing/stasis; and that the macrophage is the major cell source of NO.
Hazlett
Linda D
LD
Department of Anatomy/Cell Biology, Wayne State University, Detroit, MI 48201, USA. lhazlett@med.wayne.edu
McClellan
Sharon
S
Goshgarian
Christopher
C
Huang
Xi
X
Thakur
Archana
A
Barrett
Ronald
R
D000818:Animals; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D054426:Chemokine CXCL2; D018925:Chemokines / Q000378:metabolism; D003315:Cornea / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D004797:Enzyme-Linked Immunosorbent Assay; D015818:Eye Infections, Bacterial / Q000276:immunology* / Q000382:microbiology; D005260:Female; D006146:Guanidines / Q000627:therapeutic use; D007109:Immunity; D007150:Immunohistochemistry; D007375:Interleukin-1 / Q000378:metabolism; D007634:Keratitis / Q000276:immunology* / Q000382:microbiology; D019402:Macrophage Inflammatory Proteins / Q000378:metabolism; D008264:Macrophages / Q000201:enzymology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000235:genetics*; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000378:metabolism; D011552:Pseudomonas Infections / Q000276:immunology* / Q000382:microbiology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D054405:Chemokine CCL3; D054407:Chemokine CCL4; D054426:Chemokine CXCL2; D018925:Chemokines; C404915:Cxcl2 protein, mouse; D004791:Enzyme Inhibitors; D006146:Guanidines; D007375:Interleukin-1; D019402:Macrophage Inflammatory Proteins; D009573:Nitrites; D012333:RNA, Messenger; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C004479:pimagedine