Molecular effects of sodium hyaluronate on the healing of avian supracoracoid tendon tear: according to in situ hybridization and real-time polymerase chain reaction.

Hyluronic acid (HA) on tissue healing has been controversial. We examined the molecular pharmacology of HA injection at the suture site in an acute model of supracoracoid tendon laceration using chickens, an injury of a nonweight-bearing joint considered similar to the human shoulder. Expression of mRNAs encoding alpha I (I) and alphaI (III) procollagens was localized using in situ hybridization (ISH). Intensities of mRNA expression for alpha I (I) and alpha I (III) procollagens, transforming growth factor-beta1 (TGF- beta1), basic fibroblast growth factor (bFGF), and insulin-like growth factor (IGF) were determined by quantitative reverse transcription-polymerase chain reaction (RT-PCR). Histologically, chickens with HA injection (HA group) showed early restoration of continuity at the laceration site than saline-injection controls (saline-injection group). By ISH, the expression rate of cells at the lesion site that contained alpha I (I) and alpha I (III) procollagen mRNAs were somewhat higher in the HA group than in the saline-injection group. By RT-PCR, the HA- and saline-injection groups showed no significant difference in expression of alpha I (I) and alpha I (III) procollagen mRNA between weeks 1 and 6. The saline -injection group exhibited significant decrease in TGF-beta1 expression between weeks 1 and 3, and in bFGF expression between weeks 1 and 2; however, the HA group showed no such decrease. As for IGF, no difference was appreciable in both groups between weeks 1 and 6. A single injection of HA could cause earlier restoration of continuity at the lacerated site of the supracoracoid tendon.