title: Fibroblast growth factor-2-overexpressing myoblasts encapsulated in alginate spheres increase proliferation, reduce apoptosis, induce adipogenesis, and enhance regeneration following skeletal muscle injury in rats.
abstract: The fibroblast growth factor 2 (FGF-2) is known as pleiotropic cytokine with myoblast proliferative properties. In the present study, we tested the hypothesis that gene transfer of human FGF-2 via transplantation of genetically modified L8-myoblast encapsulated in alginate modulates the skeletal muscle recovery after crush injury in Wistar rats. Therefore, we performed a crush injury to the soleus muscle and transplanted alginate spheres containing myoblasts genetically modified to overexpress human FGF-2 (FGF-2) or a luciferase (LUC) cDNA at the site of injury. Animals that underwent muscle injury without transplantation of alginate spheres served as control (control). At day 4 after trauma the FGF-2 group showed significant higher mean values of cell proliferation (bromodeoxyuridine immunohistochemistry) and significant lower values of cell apoptosis (terminal deoxynucleotidyl transferase nick end labeling histology) compared to animals receiving luciferase-overexpressing myoblasts. At the same time point adiponectin expression (ACRP30 immunohistochemistry) was increased in the FGF-2 group exclusively. The p75(NTR) expression (p75(NTR) immunohistochemistry) significantly improved in both the FGF-2 and LUC group compared to the control group. Functional analysis of the injured muscle did not reveal a significant increase of the muscle force in the FGF-2 group compared to the control and LUC group 14 days after injury. In vitro analysis for 14 days of the FGF-2-modified spheres demonstrated at day 7 and day 14 a significant increase of the relative cell count as well as of the relative viable cell count in the FGF-2 myoblast spheres compared to luciferase myoblast spheres. Additionally, the expression of FGF-2 (enzyme-linked immunosorbent assay analysis) and luciferase (chemiluminescence analysis) persisted in vitro for 4 and 14 days, respectively. These results demonstrate that FGF-2-overexpressing myoblasts cannot considerably improve muscle strength but are able to modulate the proliferation as well as the apoptosis of injured muscle tissue mainly by conducting adipogenesis.
authors.affiliation: Institute for Experimental Surgery, University of Rostock, Rostock, Germany.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Stratos
authors.forename: Henning
authors.initials: H
authors.lastname: Madry
authors.forename: Robert
authors.initials: R
authors.lastname: Rotter
authors.forename: Anja
authors.initials: A
authors.lastname: Weimer
authors.forename: Johannes
authors.initials: J
authors.lastname: Graff
authors.forename: Magali
authors.initials: M
authors.lastname: Cucchiarini
authors.forename: Thomas
authors.initials: T
authors.lastname: Mittlmeier
authors.forename: Brigitte
authors.initials: B
authors.lastname: Vollmar
mesh_terms: D050156:Adipogenesis / Q000502:physiology*; D000464:Alginates / Q000737:chemistry*; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002460:Cell Line; D049109:Cell Proliferation; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D007150:Immunohistochemistry; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries*; D032446:Myoblasts / Q000166:cytology* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012038:Regeneration / Q000502:physiology*
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D016222:Fibroblast Growth Factor 2; D020723:Glucuronic Acid