SYNTHETIC/NATURAL HYBRID SCAFFOLD FOR TISSUE REGENERATION - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 318

immunopositivity at the specific region of the in vitro fibrin/PLGA
hybrid construct, mainly localized surrounding the pericellular and
interterritorial matrix. After in vivo implantation, the fibrin/PLGA
hybrid construct showed more homogeneous distribution of colla-
gen type II than in the PLGA scaffold at each time point. Analysis
of collagen type I in fibrin/PLGA hybrid constructs showed moder-
ate positive immunoreactivity throughout the ECM of specimens at
each time point of one and two weeks postimplantation. Interest-
ingly, after four weeks' implantation, both fibrin/PLGA hybrid con-
structs and the PLGA group showed no collagen type I expression;
however, in some cases, both groups showed very weak collagen
type I expression.
The fibrin/PLGA hybrid scaffold promotes chondrogenesis of
rabbit articular chondrocytes proven by means of morphology, his-
tology, immunohistochemistry, chondrogenic gene expression, and
sGAG production. This study suggests that the fibrin/PLGA hybrid
scaffold may serve as a potential cell delivery vehicle and a struc-
tural basis for in vitro development of tissue-engineered articular
cartilageconstructs.Futurestudiesusingappropriateanimalmodel
for an autologous in vivo system are necessary to further validate
the feasibility of fibrin/PLGA hybrid constructs for articular carti-
lage restoration.
16.2.2 Fibrin/PLGA Hybrid Scaffolds for IVD in vitro
The intervertebral disc (IVD) is the cornerstone of the joint com-
plex comprising the spinal motion segment. The IVD functions to
permit limited motion and flexibility, while maintaining segmental
stability by absorbing and distributing external loads. The structure
of the normal IVD includes the nucleus pulposus (NP) composed
primarily of proteoglycans and collagen type II with a capacity to
absorbanddistributeloadandtheouterannulusfibrosus(AF)with
well-organized layers consisting of collagen type II and collagen
type I serving to stabilize the motion segment. The structure and
function of the IVD may be altered by processes including normal
physiological aging, mechanical factors, that is, trauma and repeti-
tive stress, segmental instability of the spine, and inflammatory and