Objective—To characterize gelatinases in bronchoalveolar
lavage fluid (BALF) and gelatinases produced
by alveolar macrophages of healthy calves.
Sample Population—Samples of BALF and alveolar
macrophages obtained from 20 healthy 2-month-old
Procedure—BALF was examined by use of gelatin
zymography and immunoblotting to detect gelatinases
and tissue inhibitor of metalloproteinase (TIMP)-1
and -2. Cultured alveolar macrophages were stimulated
with lipopolysaccharide (LPS), and conditioned
medium was subjected to zymography. Alveolar
macrophage RNA was used for reverse transcriptasepolymerase
chain reaction assay of matrix metalloproteinases
(MMPs), cyclooxygenase-2, and inducible
nitric oxide synthase.
Results—Gelatinolytic activity in BALF was evident at
92 kd (14/20 calves; latent MMP-9) and 72 kd (18/20;
latent MMP-2). Gelatinolytic activity was evident at 82
kd (10/20 calves; active MMP-9) and 62 kd (17/20;
active MMP-2). Gelatinases were inhibited by metal
chelators but not serine protease inhibitors.
Immunoblotting of BALF protein and conditioned
medium confirmed the MMP-2 and -9 proteins.
Endogenous inhibitors (ie, TIMPs) were detected in
BALF from all calves (TIMP-1) or BALF from only 4
calves (TIMP-2). Cultured alveolar macrophages
expressed detectable amounts of MMP-9 mRNA but
not MMP-2 mRNA.
Conclusions and Clinical Relevance—Healthy
calves have detectable amounts of the gelatinases
MMP-2 and -9 in BALF. Endogenous inhibitors of
MMPs were detected in BALF (ie, TIMP-1, all calves;
TIMP-2, 4 calves). Lipopolysaccharide-stimulated alveolar
macrophages express MMP-9 but not MMP-2
mRNA. The role of proteases in the pathogenesis of
lung injury associated with pneumonia has yet to be
determined. (Am J Vet Res 2004;65:163–172)
Objective—To determine the quantity (concentration) and quality (molecular weight) of synovial fluid hyaluronan with respect to presence and severity of osteoarthritis in stifle joints of dogs.
Animals—21 purpose-bred dogs and 6 clinically affected large-breed dogs (cranial cruciate ligament [CrCL] disease with secondary osteoarthritis).
Procedures—Research dogs underwent arthroscopic surgery in 1 stifle joint to induce osteoarthritis via CrCL transection (CrCLt; n = 5 stifle joints), femoral condylar articular cartilage groove creation (GR; 6), or meniscal release (MR; 5); 5 had sham surgery (SH) performed. Contralateral stifle joints (n = 21) were used as unoperated control joints. Synovial fluid was obtained from research dogs at time 0 and 12 weeks after surgery and from clinically affected dogs prior to surgery. All dogs were assessed for lameness, radiographic signs of osteoarthritis, and pathologic findings on arthroscopy as well as for quantity and quality of hyaluronan.
Results—Clinically affected dogs had significantly greater degrees of pathologic findings, compared with dogs with surgically induced osteoarthritis (ie, those with CrCLt, GR, and MR stifle joints), and with respect to lameness scores, radiographic signs of osteoarthritis, pathologic findings on arthroscopy, and synovial fluid hyaluronan concentration. Synovial fluid from stifle joints of dogs with surgically induced osteoarthritis had hyaluronan bands at 35 kd on western blots that synovial fluid from SH and clinically affected stifle joints did not.
Conclusions and Clinical Relevance—Synovial fluid hyaluronan quantity and quality were altered in stifle joints of dogs with osteoarthritis, compared with control stifle joints. A specific hyaluronan protein fragment may be associated with early pathologic changes in affected joints.