TITLE:
The Knee Joint Tissues Differ Significantly in TGFβ1 Expression and Its Sensitivity
AUTHORS:
Sadanand Fulzele, Monte Hunter, Rajnikumar Sangani, Norman Chutkan, Carlos Isales, Mark W. Hamrick
KEYWORDS:
Meniscus; Outer Meniscus; Inner Meniscus; TGFβ1; Articular Cartilage
JOURNAL NAME:
CellBio,
Vol.2 No.4,
December
4,
2013
ABSTRACT: The knee joint is the largest and most complex joint in the human body. In
this study, we investigated TGFβ1
expression in the outer meniscus, inner meniscus and articular cartilage of
rabbit and human knee tissue (outer and inner menisci) in order to determine
the potential role of this factor in normal meniscal function. We also examined
the potential of TGF-β1 stimulation
to promote tissue regeneration in the two different regions of rabbit knee
meniscus tissue. Immunohistochemical investigations of TGF-β1 were performed on rabbit and human knee tissue. The rabbit
outer, inner and articular cartilage cells were culture and stimulated with
TGF-β1 followed by cell proliferation
assay and extracellular matrix analysis. Regulatory studies were performed
using TGF-β1 inhibitors SB-431542 and
PD98059. Gene expression was analyzed by quantitative polymerase chain
reaction. We found marked regional variation in the expression of TGF-β1 in rabbit and human knee. TGF-β1
expressions are relatively greater in the outer meniscus than inner meniscus.
Furthermore, we found that exogenous TGF-β1
stimulation increased cell proliferation and aggrecan synthesis more so in the
outer than in the inner meniscus. Articular cartilage tissue shows moderate
levels of cell proliferation and ECM synthesis when compared with outer and
inner meniscus. These findings suggest that growth factors used to enhance the
repair and regeneration of meniscal tissue should be tailored to enhance
region-specific variation in cell proliferation and extracellular matrix
synthesis.