Platelet-rich plasma enhances recovery of skeletal muscle atrophy after immobilization stress in rat: A histological and immunohistochemical study

Abstract

Background: Immobilization stress occurs in various clinical situations as chronic inflammatory and neuromuscular diseases leading to disuse muscle atrophy. Recovery of skeletal muscle after immobilization is slow and incomplete. Platelet-rich plasma (PRP) was previously used in improving traumatic muscle injuries, yet, its role in accelerating muscle recovery upon immobilization stress has not been studied. Aim of the work: to study the possible adjuvant effect of PRP on skeletal muscle atrophy during recovery after immobilization stress in rat using different histological and immunohistochemical teschniques.Material and Methods: Thirty-six adult male rats were equally divided into four groups; control, immobilization stress (restrained in reduced sized cages for 4 weeks), recovery alone (4 weeks), and recovery & PRP groups. Skeletal muscle specimens were processed for histological and immunohistochemical studies.Results: Immobilized group showed splitting of the muscle fibers, internalization of the nuclei, loss of striation, undulated disrupted sarcolemma with signs of inflammation. Ultrastructural examination revealed myocytes with indented nuclei, mitochondria of abnormal shape and size, atrophied myofibrils with loss of myofilaments and splitting of myofibrils. A significant reduction of both mean muscle fiber cross sectional area and area percentage was reported together with a significant downregulation in desmin immunohistochemical expression. Recovery group revealed persistence of histological and immunohistochemical alterations. Recovery & PRP group showed a near normal morphology together with a non-significant difference in desmin immunohistochemical expression compared to control.Conclusion: PRP offered a promising improvement of skeletal muscle atrophy after immobilization stress. It is recommended to apply adjuvant PRP therapy with recovery rather than recovery alone.