Introduction: Platelet-rich plasma (PRP) is a platelet concentration obtained from a few millilitres of blood. It releases several growth factors and can enhance tissue repair(). The aim of the study was to evaluate the efficacy and the safety of PRP in the treatment of experimental induced muscle lesions.

Materials and Methods: 22 adult Wistar rats were used. Blood collected from 2 rats was mixed with citrate-phosphate-dextrose and centrifuged to a gel consistency. Growth factor release was stimulated by the addition of CaCl and thrombin. Identical bilateral incisions were performed on the longissimum dorsi muscle of 20 Wistar rats. Each site was marked by placing a hollow PVC vessel containing PRP on the bottom of the defect. An empty marker was placed on the bottom of the contralateral lesion, as control. Animals were killed 40 or 60 days from surgery. Muscle samples were stained with haematoxylin-eosin. Histomorhometric parameters investigated were: number of regenerating fibres, amount of neoangiogenesis and fibrous tissue, presence of inflammatory cells, metaplasia, calcification and ossification (Leika, Quantimet SD).

Results: Treated muscles exhibited greater neoangiogenesis and a larger number of miocytes in regenerating phase compared with controls. Both groups showed a similar amount of fibrous tissue and some inflammatory cells. Metaplasia, ossification or heterotopic calcification were seen in none of the samples.

Conclusions: To our knowledge this is the first investigation of PRP in muscle healing. Data showed that PRP is effective in improve muscle healing without adverse local effects. Additional experiments are in progress in view of a clinical trial.