High rate of joint capsule matrix turnover in chronic human elbow contractures

Abstract

The joint capsule is a key component in posttraumatic joint contractures. The capsule is described as thickened, but little data exist supporting the observation. Our hypotheses were that mRNA levels of (1) collagen; (2) decorin and biglycan; (3) matrix metalloproteinases; and (4) tissue inhibitors of matrix metalloproteinases were significantly elevated in anterior joint capsules obtained from 11 patients having surgery for posttraumatic contractures when compared with nine elbows, from organ donors, that were free of contractures. Reverse transcription-polymerase chain reaction was used to evaluate mRNA expression normalized to a housekeeping gene, glyceraldehyde-3-phosphate dehydrogenase. In the joint capsules of the patients with elbow contractures, relative mRNA levels were increased for: collagen Types I, III, and V (1.5-2.5 times); biglycan (1.5 times); and matrix metalloproteinases-1, -2, -9, -13, and -15 (1.6-3.9 times). In contrast, expression of tissue inhibitors of matrix metalloproteinases-1, -2, and -4 were decreased (1/3-3/4 times) in the capsules of patients with contractures. There was no difference between the groups in relative mRNA expression for decorin, matrix metalloproteinases-8, -14 and -16, and tissue inhibitor of matrix metalloproteinase-3. The results indicate that joint capsule matrix molecule mRNA levels are altered in the chronic stages of posttraumatic elbow contractures in humans, potentially creating an environment with high matrix turnover rates.

Fig 1

A–B. (A) The mRNA expression of collagen Types I, III, and V (col-1, col-3, and col-5, respectively) normalized to GAPDH mRNA expression is shown. (B) An example of the intensity of collagen Type III and GAPDH on gel analysis is shown (bp = length of primer product in base pairs).

Fig 2

A–B. (A) The mRNA expression of biglycan and decorin normalized to GAPDH mRNA expression is shown. (B) The intensity of decorin and GAPDH expression on gel analysis is shown (bp = length of primer product in base pairs).

Fig 3

A–B. (A) The mRNA expression of MMP-1, -2, -8, -9, and -13 to GAPDH mRNA expression is shown on this graph. (B) An example of the intensity of MMP-1 and GAPDH is shown on gel analysis (bp = length of primer product in base pairs).

Fig 4

A–B. (A) The mRNA expression of MMP-14, -15, and -16 normalized to GAPDH mRNA expression is shown. (B) The intensity of MMP-14 and GAPDH on gel analysis is shown (bp = length of primer product in base pairs).

Fig 5

A–B. (A) The mRNA expression of TIMP-1, -2, -3, and -4 normalized to GAPDH mRNA expression is shown. (B) An example of the intensity of TIMP-2 and GAPDH is shown on gel analysis.