Role of inflammation in tendon injuries studied

Typical microscopic appearance of normal and injured equine flexor tendons.
Typical microscopic appearance of normal and injured equine flexor tendons.
Longitudinal histology sections stained with Haematoxylin and Eosin showing: (A) normal superficial digital flexor tendon (SDFT) from a 6 year old horse showing regular arrangement of parallel collagen fibrils. Scale bar = 100 µm. (B) Sub-acutely injured SDFT 3 weeks post injury from a 4 year old horse showing marked cellular infiltration (black arrows). Scale bar = 100 µm. (C) Chronic injured SDFT >3 months post injury from a 12 year old horse showing increased cellularity and poor organisation of collagen fibrils compared to (A). Scale bar = 100 µm.

A recent British study investigated the role of prostaglandins and inflammation-resolving mediators in naturally occurring equine tendon injuries.

The study, published in the open-access journal PLoS ONE, by Dr Stephanie Dakin and other researchers from the Royal Veterinary College’s Tendon Biology group, showed that during early-stage injury, alterations in tendon prostaglandin metabolism and lipid mediator profiles were present compared to normal (uninjured) tendons.

Injured tendons showed an age-associated decline in expression of the inflammation-resolving lipoxin A4 receptor with concurrent increased PGE2 levels with age.

An in vitro model of tendon inflammation showed IL-1β treated tendon explants from younger but not older horses were better able to mount a protective resolving response to inflammation.

The findings from this study suggest prostaglandins such as PGE2 are implicated in the development of tendon inflammation and its ensuing resolution.

Furthermore, tendons from aged individuals exhibit a reduced capacity to resolve inflammation, which may contribute to the development of tendon re-injury.

The full study can be read online here.


Dakin SG, Dudhia J, Werling NJ, Werling D, Abayasekara DRE, Smith, RKW (2012) Inflamm-Aging and Arachadonic Acid Metabolite Differences with Stage of Tendon Disease. PLoS ONE 7(11): e48978. doi:10.1371/journal.pone.0048978




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