ABSTRACT
We have designed a composite scaffold for potential use in tendon or ligament tissue engineering. The composite scaffold was made of a cellularized alginate gel that encapsulated a knitted structure. Our hypothesis was that the alginate would act as a cell carrier and deliver cells to the injury site while the knitted structure would provide mechanical strength to the composite construct. The mechanical behaviour and the degradation profile of the poly(lactic-co-glycolic acid) knitted scaffolds were evaluated. We found that our scaffolds had an elastic modulus of 750 MPa and that they lost their physical integrity within 7 weeks of in vitro incubation. Autologous rabbit mesenchymal stem cell seeded composite scaffolds were implanted in a 1-cm-long defect created in the rabbit tendon, and the biomechanical properties and the morphology of the regenerated tissues were evaluated after 13 weeks. The regenerated tendons presented higher normalized elastic modulus of (60%) when compared with naturally healed tendons (40%). The histological study showed a higher cell density and vascularization in the regenerated tendons.
Subject(s)
Achilles Tendon/cytology , Achilles Tendon/drug effects , Lactic Acid/chemistry , Lactic Acid/pharmacology , Polyglycolic Acid/chemistry , Polyglycolic Acid/pharmacology , Tissue Engineering/methods , Tissue Scaffolds/chemistry , Achilles Tendon/metabolism , Achilles Tendon/physiology , Alginates/chemistry , Animals , Biomechanical Phenomena/drug effects , Female , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , Hydrogen-Ion Concentration , Polylactic Acid-Polyglycolic Acid Copolymer , Rabbits , Regeneration/drug effects , Tensile Strength/drug effects , ViscosityABSTRACT
It is well known today that mechanical forces are one of the important factors that induce a variety of cellular responses including morphological changes, protein synthesis, and gene expression and which are involve in tissue remodelling. We studied the effect of uniaxial cyclic stretching on the proliferation, collagens, and tenascin C mRNA expression of fibroblasts under different concentrations of foetal bovine serum. Proliferation was studied by cell cycle analysis, mRNA expression of collagen and tenascin C was studied by RT-PCR. Human fibroblasts were grown in silicon sheet coated with 1% gelatin. Cyclic stretching (5% elongation) was applied at 0.5 Hz (30 cycle/min), for 24 h with two concentrations of the serum (0.5%, 10% FBS). We showed that stretching enhances the synthesis of collagen and tenascin C, but do not act on the proliferation. In contrast, higher concentration of serum enhances the proliferation. These findings suggest that both mechanical stretching and serum concentration can modulate proliferation and extra cellular matrix synthesis in human fibroblasts.
