J.P. Punke, R.Y. Au² , A.Y. Au², P.V. Phan², S.C. Budsberg¹, C.G. Frondoza².
¹University of Georgia, Athens, GA, United States, ²Nutramax Laboratories, Inc., Edgewood, MD, United States

ACVS Abstract 2007 

Periarticular tissues are known to participate in inflammatory processes that lead to osteoarthritis (OA). Recent studies have illustrated the need to better understand the pathogenesis of feline OA.

We hypothesize that propagated feline osteoblasts, ligament cells, and tenocytes can be used to evaluate the pathogenesis of OA due to their ability to respond to cytokine activation by producing prostaglandin E2 (PGE2). Feline osteoblasts, ligament cells, or tenocytes were propagated separately in monolayer culture or in microcarrier cultures. Collagen type I production was visualized by fluorescent immunostaining microscopy and Western blot. Cellular morphology was analyzed by phase-contrast and light microscopy. For activation analyses, cells were incubated in monolayer or in microcarrier cultures with media alone or activators, interleukin-1-beta (IL-1b) and tumor necrosis factor-alpha (TNF-a). PGE2 levels were measured by immunoassay.

Osteoblasts, ligament cells, and tenocytes were isolated with ease and proliferated in monolayer, as well as in microcarrier cultures. Light microscopy of microcarrier cultures showed adherent cells organized into several layers of cells surrounded by extracellular matrix. Type I collagen production was verified by intense immunostaining and by Western blots. Type I collagen band- ing at 160 kDa was identified in spent microcarrier culture supernatant.

All three cell types propagated in either culture system responded to IL-1b and TNF-a activation by a 50- to 200-fold increase in PGE2 synthesis. In conclusion, feline osteoblasts, ligament cells, and tenocytes attach, proliferate, and remain metabolically active in tissue culture. Thus, they can be employed to evaluate inflammatory processes involved in the pathogenesis of OA.