Inflammatory mediators in autoimmune lacrimal gland disease in MRL/Mpj mice.
OBJECTIVE
MRL/MpJ-fas(+)/fas(+) (MRL/+) and MRL/MpJ-fas(lpr)/fas(lpr) (MRL/lpr) mice are congenic substrains of mice that have spontaneously developing lacrimal and salivary gland inflammation and are models for the human disorder Sjögren's syndrome. Nitric oxide (NO) and tumor necrosis factor (TNF)-alpha are proinflammatory and potential mediators of tissue damage. The presence of the inducible form of nitric oxide synthase (iNOS), which catalyzes the production of NO, and the presence TNF-alpha in the lacrimal glands of MRL/MpJ mice were assessed.


METHODS
Lacrimal glands from MRL/+ and MRL/lpr mice, at ages 1 through 9 months, were evaluated by real-time RT-PCR for iNOS and TNF-alpha mRNA and by immunohistochemistry for the presence of iNOS and of TNF-alpha. Age-matched BALB/c lacrimal glands were used as the control.


RESULTS
By quantitative real-time PCR (qPCR), mRNA for iNOS was detected in the lacrimal glands in significantly greater amounts in both MRL/+ (median, normalized to 18S rRNA, 2.90; P < 0.0003) and MRL/lpr mice (median 6.84, P < 0.001) than in BALB/c mice (median 0.34). By qPCR, mRNA for TNF-alpha in the lacrimal glands was detected in significantly greater amounts in aged MRL/+ mice than in BALB/c mice (median, normalized to actin, 221.8 vs. 77.8, P = 0.011) and in MRL/lpr mice than in BALB/c mice (median 136.7 vs. 72.5, P = 0.001). Immunohistochemistry demonstrated both iNOS and TNF-alpha in scattered mononuclear cells throughout the lacrimal glands and in mononuclear cells at the junction of the focal inflammatory infiltrates and normal acinar tissue in both MRL/+ and MRL/lpr mice.


CONCLUSIONS
As demonstrated by the greater presence of iNOS and TNF-alpha in the lacrimal glands of MRL/MpJ mice than in control glands, both NO and TNF-alpha are potential mediators of lacrimal gland damage in these murine models of Sjögren's syndrome.
Jabs
Douglas A
DA
Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA. djabs@jhmi.edu
Gérard
Hérvé C
HC
Wei
Yuewang
Y
Campbell
Adam L
AL
Hudson
Alan P
AP
Akpek
Esen Karamursel
EK
Lee
Bella
B
Prendergast
Robert A
RA
Whittum-Hudson
Judith A
JA
D000818:Animals; D001327:Autoimmune Diseases / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D007124:Immunoenzyme Techniques; D018836:Inflammation Mediators / Q000378:metabolism*; D007765:Lacrimal Apparatus / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D019463:Mice, Inbred MRL lpr; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012859:Sjogren's Syndrome / Q000378:metabolism* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics* / Q000378:metabolism
D018836:Inflammation Mediators; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse