Introduction: Nowadays, platelet-rich plasma injection (PRP) has become a common treatment in the scope of reconstructive plastic surgery and trauma. PRP contains varies growth factors that accelerate cell regeneration and differentiation.
Objective of the Study: Evaluate the effect of a single-shot injection of PRP on induced muscle spindle injury.
Materials and Methods: Forty rats were categorized into three groups; control, one and three weeks after muscle injury. The injured muscles were either treated with PRP or left without treatment. The muscle specimens were processed for histological and immunohistochemical staining for desmin and Ki-67 followed by computer image analysis.
Results: PRP administration resulted in appearance of muscle spindles among numerous regenerating muscle fibers and numerous newly formed blood vessels at 1st week of injury. Meanwhile, untreated group exhibited granulation tissue accompanied inflammatory cell infiltration with marked amount of deposited collagen. Three weeks PRP treated group showed well differentiated muscle spindles surrounded by outer multi-laminar connective tissue capsule which were similar to the control group. The desmin was expressed in regenerating spindle fibers as well as in intact muscle spindles and the expression pattern of these intermediate filaments was more intense in PRP treated groups. A significant reduction in the Ki-67 level was detected in the apparently normal newly formed spindle muscle in PRP treated group.
Conclusion: A single dose PRP plays a major role in promoting the proliferation, differentiation and has a neurotrophic function in muscle spindle regeneration. These findings provide useful and indispensable application of PRP in muscle spindle injury.