Metrenperone enhances collagen turnover and remodeling in the early stages of healing of tendon injury in rabbit.
BACKGROUND
This study evaluated the effects of metrenperone on healing of unilateral, collagenase-induced lesions in the Superficial Digital Flexor Tendons (SDFT) of rabbits.


METHODS
After controlled injury of the left SDFT, nine rabbits received daily treatment with metrenperone for 28 days. Another nine were untreated controls; in both groups the contra-lateral tendons served as uninjured controls. Histological and ultrastructural changes, mechanical properties, dry weight, collagen content, and amount of DNA in healing and control tendons were assessed 28 days after injury.


RESULTS
Restoration of structural hierarchy was more organized in treated than in untreated tendons while cellularity was greater in the latter. At the ultrastructural level, collagen in treated lesions was predominantly in the form of small-diameter, new fibrils, with few large, old fibrils; in untreated lesions there was a high proportion of large, old fibrils but relatively few small, new ones. The amount of DNA in untreated injuries was much greater than in normal tendons, while in treated lesions it was not significantly different from that of uninjured controls. There were no significant differences in total collagen, stiffness and ultimate strength of injured, treated, and untreated tendons 28 days after injury. Both were significantly weaker than their corresponding contralaterals.


CONCLUSIONS
The findings suggest that metrenperone had positive effects on collagen turnover, remodelling, and organization during acute inflammation and fibroplasia. Provided that the new fibrils subsequently matured in a normal manner, mechanical characteristics of the organized scar should be better than those of an untreated lesion.
Oryan
Ahmad
A
Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran. oryan@shirazu.ac.ir
Silver
Ian A
IA
Goodship
Allen E
AE
D000818:Animals; D001696:Biomechanical Phenomena; D003094:Collagen / Q000378:metabolism*; D017364:Collagenases; D004247:DNA / Q000032:analysis; D005260:Female; D010880:Piperidines / Q000494:pharmacology*; D011817:Rabbits; D058830:Serotonin 5-HT2 Receptor Antagonists / Q000494:pharmacology*; D013708:Tendon Injuries / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D013710:Tendons / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D013718:Tensile Strength / Q000187:drug effects; D014945:Wound Healing / Q000187:drug effects*
D010880:Piperidines; D058830:Serotonin 5-HT2 Receptor Antagonists; D003094:Collagen; D004247:DNA; D017364:Collagenases; C046881:metrenperone