The impact of skeletal muscle injury on the expression of Laminin and its role in regeneration

Abstract

Background:Laminins are high-molecular-weight proteins in the extracellular matrix; it is a major component ofthe basal lamina, influencing cell differentiation, migration, and adhesion. Laminin affects cellgrowth, besides effects in wound healing and embryonic development.Objective:The present study aims to assess the histological changes taking place during skeletal musclehealing.Methods:The Extensor digitorum longus muscle of 45 male rabbits was set as a skeletal muscle injury modeland examined 3&6 weeks after initiation of injury. These animals were divided into three groupscontrol (A) group with no injury, group (B) at 3rdpost-injury week, group (C) at 6th post-injury week. The muscle tissues were prepared and examinedhistologically using H&E and immunohistochemically using Laminin antibodies. Aperio image scopesoftware is used to analyze immunohistochemical reactivity quantitatively.The degeneration and regeneration process were overlapping with each other both in time andcellular morphological changes. Early myoblast like cell appearance and new myotube formation wasrecorded during the 3rd week. By the end of the6th-week postoperatively, the muscle histological maturation and muscle fascicles were noticed.Results:Immunohistochemical reactivity of Laminin antibody showed an intense reactivity in the 3rd-weekgroup while a less intense reactivity in the control and 6th-week groups’.A quantitative assessmentof Laminin using Aperio soft wear showed that the 3rd-week group has an intensity of 0.724 ± 0.03pixel, while the 6th week’s group was 0. 321 ± 0.02 pixel and the control groups was 0.293 ± 0.02pixel. The differences were statistically significant, P-value 0.0001.Conclusion: The process of regeneration is a dynamic type where degeneration andregeneration superimposed each other.