Role of insulin like growth factor-I in repair response in immature cartilage.
OBJECTIVE
The purpose of this study was to investigate the effects of exogenous local Insulin like growth factor-I (IGF-I) on the repair of full-thickness articular cartilage defects in immature rabbits.


METHODS
Thirty-six skeletally immature New Zealand rabbits between 6 and 8 weeks old were used. A single defect, 3.5-mm-wide by 4-mm-deep full-thickness articular cartilage defect in the medial femoral condyle, was created. The defect was either filled with a collagen sponge or with a collagen sponge impregnated with 5 mug of recombinant IGF-I. The animals were sacrificed at 4, 8 or 12 weeks, and the repair tissue was examined macroscopically and histologically. Repair tissue was also examined immunohistochemically for the presence of type-I collagen, type-II collagen and PCNA at all weeks.


RESULTS
Newly formed tissue in all of the defects in the IGF-I group had the gross, histological and histochemical appearance of a smooth, intact hyaline articular cartilage. The average total scores on the histological grading scale were significantly better (p<0.05) for the defects treated with recombinant IGF-I at all time points. Immunostaining with an antibody against type-II collagen showed the diffuse presence of the repair cartilage in the IGF-I treated defects. The control groups demonstrated minimum staining with type-II collagen antibody.


CONCLUSIONS
These findings suggest that repair of full-thickness immature cartilage defects can be enhanced by recombinant IGF-I.
Tuncel
Mehmet
M
Orthopaedics and Traumatology Department, Medical Faculty, Erciyes University, Kayseri 38039, Turkey. mtuncel@erciyes.edu.tr
Halici
Mehmet
M
Canoz
Ozlem
O
Yildirim Turk
Cemil
C
Oner
Mithat
M
Ozturk
Figen
F
Kabak
Sevki
S
D000818:Animals; D002358:Cartilage, Articular / Q000187:drug effects* / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D024042:Collagen Type I / Q000378:metabolism; D024043:Collagen Type II / Q000378:metabolism; D004195:Disease Models, Animal; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011817:Rabbits; D011994:Recombinant Proteins / Q000494:pharmacology; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects* / Q000502:physiology
D024042:Collagen Type I; D024043:Collagen Type II; D018809:Proliferating Cell Nuclear Antigen; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I