Influence of Platelet Rich Plasma on the Skeletal Muscle Fibrosis after Limb Lengthening in Mice

CATEGORY: Basic Sciences/Biologics INTRODUCTION/PURPOSE: Skeletal muscle fibrosis induced by the increase of collagen occurs after limb lengthening which is also called distraction osteogenesis. Although there are studies about influence of platelet rich plasma (PRP) on tissues healing process, its effectiveness is still controversial. The aim of this study was to examine whether PRP decreased the skeletal muscle fibrosis induced by limb lengthening. METHODS: Tibial osteotomy was done to 8-week-old wild type mice. Tibia was lengthened at a rate of 0.42 mm/day during 2 weeks, launching 1 week after tibial osteotomy. Just after lengthening completed (3 weeks after tibial osteotomy), PRP was injected into the gastrocnemius muscle (PRP group). As a sham group, phosphate buffered saline (PBS) was injected into the gastrocnemius muscle (non-PRP group). The gastrocnemius (GC) muscles were taken and analyzed at 4, 6, 8 and 10 weeks after tibial osteotomy. RESULTS: The fibrotic area of the GC muscles in the both groups increased at 4 weeks after tibial osteotomy in histological analysis (Figure). Then, it gradually decreased at 6, 8, and 10 weeks after tibial osteotomy. There were no significant differences between the both groups at 6, 8, and 10 weeks after tibial osteotomy. Hydroxyproline, which was a major constituent of collagen, increased in the non-PRP and PRP groups by limb lengthening as well. However, significant changes were not found between the both groups at all any points. CONCLUSION: At first, we anticipated that PRP should reduce the skeletal muscle fibrosis after limb lengthening significantly. But our results implied that PRP did not decrease the skeletal muscle fibrosis induced by limb lengthening.