Rabbit extrasinovial regenerating tendon: an experimental study

The roles of the extrasynovial tendon cells (Achilles tendon) throughout the repairing process following injury are controversial. This study was performed to investigate the ultrastructural features of activated tenocytes and collagen synthesis experienced while healing after partial tenotomy and repair.Adult rabbit Achilles tendons were partially tenotomized. Before the suture of the paratenon, the borders of the surgical dissection were treated with different substances copolimerized with hydrogel. Hydrogel non-treated, tenotomized tendons were considered as controls. The rest of the samples were treated with hydrogel alone or hydrogel with E-vitamin. Rabbit legs were immobilized for 3, 10, 20 and 30 days. Samples from tenotomized and normal tendons were embedded in parafin and in Spurr and Araldite resins by conventional methods.With LM, a more pronounced healing process was observed in tendons treated with hydrogels if compared with controls, but this comparative study needs further investigation. During the process of repair, different stages can be identified: inflammation, revascularization and angiogenesis, cell proliferation, collagen synthesis and fibrillogenesis, and alignment/organization of collagen fibers into bundles oriented in the longitudinal axis of the tendon.

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The Effect of Ciprofloxacin on Tendon, Paratenon, and Capsular Fibroblast Metabolism

The American Journal of Sports Medicine ◽

10.1177/03635465000280031401 ◽

2000 ◽

Vol 28 (3) ◽

pp. 364-369 ◽

Cited By ~ 108

Author(s):

Riley J. Williams ◽

Erik Attia ◽

Thomas L. Wickiewicz ◽

Jo A. Hannafin

Keyword(s):

Cell Proliferation ◽

Achilles Tendon ◽

Protease Activity ◽

Collagen Synthesis ◽

Culture Media ◽

Fibroblast Cell ◽

Inhibitory Effect ◽

Proteoglycan Synthesis ◽

Ground Substance

The pathologic mechanisms underlying fluoroquinolone-induced tendinopathy are poorly understood. The observed incidence of tendinitis and tendon rupture in patients treated with ciprofloxacin hydrochloride suggests that the fluoroquinolone antibiotics alter tendon fibroblast metabolism. The purpose of this study was to examine the effect of ciprofloxacin on fibroblast metabolism in vitro. Canine Achilles tendon, paratenon, and shoulder capsule specimens were maintained in culture with ciprofloxacin (5, 10, or 50 g/ml). Fibroblast proliferation, collagen synthesis, proteoglycan synthesis, and matrix-degrading activity were analyzed. Incubation of Achilles tendon, Achilles paratenon, and shoulder capsule fibroblasts with ciprofloxacin resulted in a statistically significant 66% to 68% decrease in cell proliferation compared with control cells at day 3 in culture. Ciprofloxacin caused a statistically significant 36% to 48% decrease in collagen synthesis compared with controls in all fibroblast cultures. Ciprofloxacin caused a statistically significant 14% to 60% decrease in proteoglycan synthesis in all fibroblast cell lines. Compared with unstimulated control fibroblasts, culture media from Achilles tendon, paratenon, and shoulder capsule cells that were exposed to ciprofloxacin demonstrated statistically significant increases in matrix-degrading proteolytic activity after 72 hours in culture. This study demonstrates that ciprofloxacin stimulates matrix-degrading protease activity from fibroblasts and that it exerts an inhibitory effect on fibroblast metabolism. The increase in protease activity and the inhibition of both cell proliferation and the synthesis of matrix ground substance may contribute to the clinically described tendinopathies associated with ciprofloxacin therapy.

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