Corticosteroids reduce the tensile strength of isolated collagen fascicles.

Abstract

BACKGROUND:

Overuse tendon injuries are frequent. Corticosteroid injections are commonly used as treatment, although their direct effects on the material properties of the tendon are poorly understood.

PURPOSE:

To examine the influence of corticosteroids on the tensile strength of isolated collagen fascicles.

STUDY DESIGN:

Controlled laboratory study.

METHODS:

Single strands (300-500 mum) of rat-tail collagen fascicles were incubated in either high (1 mL of 40 mgmL(-1) mixed with 0.5 mL saline 9%) or low (1 mL of 40 mgmL(-1) mixed with 2 mL saline 9%) concentration of methylprednisolone acetate (Depomedrol) for 3 or 7 days, while the control segment from the same fascicle was kept in saline (N = 64). After the incubation period, the fascicles underwent displacement to failure in a mechanical test rig at 0.13 mm/s, and thereafter hydroxylysyl pyridinoline and lysyl pyridinoline cross-link content was evaluated in a high-performance liquid chromatography system. Data for each group were analyzed with a 2-way analysis of variance (time x incubation) for ultimate stress (mean +/- standard deviation).

RESULTS:

In the high-concentration groups, strength was reduced after 3 (16.6 +/- 4.6 MPa) and 7 (8.6 +/- 1.7 MPa) days compared to the controls (30.2 +/- 5.0 MPa and 25.6 +/- 4.6 MPa, respectively; P < .05). In the low-concentration groups, strength was reduced after 3 (12.0 +/- 3.1 MPa) and 7 days (10.9 +/- 2.5 MPa) compared to the controls (31.5 +/- 5.0 MPa and 32.4 +/- 5.6 MPa, respectively; P < .05). The amount of cross-linking was unaffected by the intervention.

CONCLUSION:

Data show that the tensile strength of isolated fascicles is markedly reduced after 3- and 7-day incubation in both high and low concentration of corticosteroids, although the observed effect on whole tendon remains unknown.

CLINICAL RELEVANCE:

Corticosteroids may weaken specific regions of the injected tendon and leave it more prone to rupture. This weakening effect is manifested in the individual collagen fascicles that constitute the tendon.

• Authors: Bjarki Thor Haraldsson, Henning Langberg, Per Aagaard, Anne-Marie Zuurmond, Benno van El, Jeroen Degroot, Michael Kjaer, S Peter Magnusson
• Journal: The American journal of sports medicine (Am J Sports Med) Vol. 34 Issue 12 Pg. 1992-7 (Dec 2006) ISSN: 0363-5465 [Print] United States
• PMID: 16902230 (Publication Type: Journal Article)

Chemical References

• Glucocorticoids
• Methylprednisolone Acetate
• Collagen
• Methylprednisolone

Topics

• Animals
• Collagen (physiology)
• Glucocorticoids (pharmacology, therapeutic use)
• In Vitro Techniques
• Male
• Methylprednisolone (analogs & derivatives, pharmacology)
• Methylprednisolone Acetate
• Rats
• Tendon Injuries (drug therapy)
• Tensile Strength (drug effects)