Scaffold-aided repair of articular cartilage studied by MRI.
OBJECTIVE
The objective of the study was to evaluate the ability of the noninvasive magnetic resonance techniques to monitor the scaffold-aided process of articular cartilage repair.


METHODS
Defects of 4 mm in diameter and 3 mm in depth were created in right knees of 30 adolescent white New Zealand rabbits. Fourteen rabbits were implanted with poly(lactide-co-glycolic acid) (PLGA) scaffold trimmed to match the size and the shape of the defect (PLGA+ group). No procedure was applied to the remaining 16 animals (PLGA- group). Animals were sacrificed sequentially at 4, 12, and 24 weeks after the surgery and magnetic resonance T (2)-weighted images (400 MHz) of the dissected bone plugs at eight different echo times were taken to derive T (2) relaxation time. The images and the T (2) time dependencies versus the tissue depth were statistically analyzed. Histological results of bone plugs were evaluated using semiquantitative histological scales.


RESULTS
The results obtained for PLGA repair tissue were evaluated versus the PLGA- group and the healthy tissue harvested from the opposite knee (reference group), and compared with histological results (hematoxylin and eosin staining). The magnetic resonance images and T (2) relaxation time profiles taken 4 weeks after surgery for both the PLGA- and PLGA+ group did not reveal the tissue reconstruction. After 12 weeks of treatment T (2) time dependence indicates a slight reconstruction for PLGA+ group. The T (2) time dependence obtained for PLGA+ samples taken after 24 weeks of treatment resembled the one observed for the healthy cartilage, indicating tissue reconstruction in the form of fibrous cartilage. The tissue reconstruction was not observed for PLGA- samples.


CONCLUSIONS
The study revealed correlation between magnetic resonance and histology data, indicating the potential value of using MRI and spatial variation of T (2) as the noninvasive tools to evaluate the process of articular cartilage repair. It also suggested, that the PLGA scaffold-aided treatment could help to restore the proper architecture of collagen fibrils.
Zalewski
Tomasz
T
Department of Macromolecular Physics, Adam Mickiewicz University, Ul. Umultowska 85, Poznań 61-614, Poland. tomekz@amu.edu.pl
Lubiatowski
Przemysław
P
Jaroszewski
Jacek
J
Szcześniak
Eugeniusz
E
Kuśmia
Sławomir
S
Kruczyński
Jacek
J
Jurga
Stefan
S
D000818:Animals; D002358:Cartilage, Articular / Q000473:pathology*; D007719:Knee Joint / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D011100:Polyglycolic Acid / Q000627:therapeutic use*; D011817:Rabbits; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds; D014945:Wound Healing / Q000502:physiology*
D011100:Polyglycolic Acid