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Growth factor expression after supraspinatus tear: a quantitative polymerase chain reaction (PCR) study in rats
Jorge Díaz Heredia1, M A Ruiz Iban2, J Martínez-Botas3,4
1Unidad de Hombro y Codo, Servicio de Traumatología y Cirugía Ortopédica, Hospital Universitario Ramón y Cajal, Madrid, Spain. drdiazheredia@gmail.com.
Introduction:
The objective of this study was to evaluate the temporal expression pattern of three different growth factors (VEGF, IL-1β, and TGF-1β) in a supraspinatus tendon lesion in an animal model. The hypothesis of this study is that there are variations in the expression of these factors in the first 8 weeks after injury.
Materials And Methods:
A full thickness defect was made in the supraspinatus tendon of 40 rat shoulders. The animal were sacrificed at 0, 3, 7, 14 and 56 days after injury and three tissue samples were obtained: bone from the tendon footprint; the supraspinatus tendon stump, and a fragment of the myotendinous junction. After mRNA extraction, quantitative PCR analysis was performed, and the expression of three different growth factors were evaluated in each zone.
Results:
There was an increased expression of IL-1β during the first week after injury at all levels evaluated with a clear peak in the first day after injury. There was also a significant increase in TGF-1β expression levels all along the first week in the three zones. There were no variations in VEGF expression in the three zones along the 8 weeks.
Conclusion:
IL-1β was expressed predominantly in the initial stages after injury; TGF initiated its expression after the initial phase since day three, whereas VEGF remained basically unchanged during the entire process.
