Morin exerts antiosteoarthritic properties: an in vitro and in vivo study

Morin is a flavonoid isolated from members of the Moraceae family. Morin has been reported to possess antioxidative and anticarcinogenic activities. However, the antiosteoarthritic properties of morin have not been investigated. In this study, we evaluate the antiarthritic properties of morin through in vitro and in vivo studies. We examined the effects of morin on the expression levels of matrix metalloproteinase (MMP)-3, MMP-13 and tissue inhibitors of metalloproteinase (TIMP)-1 in interleukin-1β (IL-1β)-induced rat chondrocytes by realtime polymerase chain reaction and Western blotting. The effects of morin on the phosphorylation of mitogen-activated protein kinases were also investigated. The in vivo antiosteoarthritic effects of morin were evaluated in the rat model of anterior cruciate ligament transection (ACLT)-induced osteoarthritis (OA). We found that morin inhibited the expression of MMP-3 and MMP-13 and increased the expression of TIMP-1 in IL-1β-induced rat chondrocytes. In addition, morin inhibited IL-1β-induced phosphorylation of extracellular signal-regulated kinase and p38. For the in vivo study in a rat model of OA induced by ACLT, in which morin was orally administered to rat, the results show that morin suppressed cartilage degradation. Our results suggest that morin may be considered as a possible therapeutic agent for the treatment of OA.