Doxycycline improves cage activity, but not exercised, supraspinatus tendon and muscle in a rat model.

The objective of this study was to investigate the effects of doxycycline, a broad-spectrum MMP inhibitor, on cage activity and exercised supraspinatus tendon and muscle using a Sprague-Dawley rat model of non-injurious exercise. Because exercise may alter muscle and tendon MMP activity and matrix turnover, we hypothesized that doxycycline would abolish the beneficial adaptations found with exercise but have no effect on cage activity muscle and tendon properties. Rats were divided into acute or chronic exercise (EX) or cage activity (CA) groups, and half of the rats received doxycycline orally.

FOXO1 regulates VEGFA expression and promotes angiogenesis in healing wounds.

Angiogenesis is a critical aspect of wound healing. We investigated the role of keratinocytes in promoting angiogenesis in mice with lineage-specific deletion of the transcription factor FOXO1. The results indicate that keratinocyte-specific deletion of Foxo1 reduces VEGFA expression in mucosal and skin wounds and leads to reduced endothelial cell proliferation, reduced angiogenesis, and impaired re-epithelialization and granulation tissue formation.

Rat supraspinatus tendon responds acutely and chronically to exercise.

The objective of this study was to identify acute responses and chronic adaptations of supraspinatus tendon to noninjurious exercise. We hypothesized that chronic exercise (EX) increases tendon mechanical properties, and a single exercise bout increases matrix metalloproteinase (MMP) activity acutely. Rats were divided into acute or chronic EX or cage activity groups.

Ibuprofen Differentially Affects Supraspinatus Muscle and Tendon Adaptations to Exercise in a Rat Model.

Background: Previous studies have shown that ibuprofen is detrimental to tissue healing after acute injury; however, the effects of ibuprofen when combined with noninjurious exercise are debated.

Hypothesis: Administration of ibuprofen to rats undergoing a noninjurious treadmill exercise protocol will abolish the beneficial adaptations found with exercise but will have no effect on sedentary muscle and tendon properties.

Study Design: Controlled laboratory study.

Effect of scapular dyskinesis on supraspinatus repair healing in a rat model.

Background: Rotator cuff tears are common conditions that often require surgical repair to improve function and to relieve pain. Unfortunately, repair failure remains a common problem after rotator cuff repair surgery. Several factors may contribute to repair failure, including age, tear size, and time from injury.

Overuse activity in the presence of scapular dyskinesis leads to shoulder tendon damage in a rat model.

Shoulder tendon injuries are common clinical conditions and are a significant source of pain and dysfunction. These conditions are more common in individuals who perform repetitive overhead activities and in individuals who have abnormal scapular kinematics, termed scapular dyskinesis (SD). However, the long term consequences associated with overuse activity in the presence of SD are unknown.

Scapular dyskinesis is detrimental to shoulder tendon properties and joint mechanics in a rat model.

Shoulder tendon injuries are frequently seen in the presence of abnormal scapular motion, termed scapular dyskinesis. The cause and effect relationship between scapular dyskinesis and shoulder injury has not been directly defined. We developed and used an animal model to examine the initiation and progression of pathological changes in the rotator cuff and biceps tendon.