Glucosamine sulfate suppresses the expressions of urokinase plasminogen activator and inhibitor and gelatinases during the early stage of osteoarthritis

BackgroundGlucosamine sulfate may have an ex vivo inhibitory effect on the plasminogen activator (PA)/plasmin system and gelatinases expression during the early development of osteoarthritis (OA).MethodsWe compared the levels of urokinase-type PA (u-PA), PA inhibitor-1 (PAI-1) and gelatinases (matrix metalloproteinase-2 and -9 [MMP-2 and -9]) in a series of chondral, meniscal, and synovial cultures of early OA after treatment with or without glucosamine sulfate.ResultsGelatin zymography revealed that glucosamine sulfate could suppress MMP-2 secretion in chondral, meniscal and synovial cultures and also decrease MMP-9 production in synovial and meniscal cultures. ELISA data also showed the suppressive effects of glucosamine sulfate on u-PA and PAI-1 production in synovial cultures at 48 h.ConclusionsOur data suggest that one of the therapeutic effects of glucosamine sulfate is to down-regulate the expressions of u-PA, PAI-1, MMP-2 and MMP-9 that underlie the destruction of articular cartilage in the early stage of OA, and therefore to delay the joint failure.