title: Pore size regulates cell and tissue interactions with PLGA-CaP scaffolds used for bone engineering.
abstract: A common subject in bone tissue engineering is the need for porous scaffolds to support cell and tissue interactions aiming at repairing bone tissue. As poly(lactide-co-glycolide)-calcium phosphate (PLGA-CaP) scaffolds can be manufactured with different pore sizes, the aim of this study was to evaluate the effect of pore diameter on osteoblastic cell responses and bone tissue formation. Scaffolds were prepared with 85% porosity, with pore diameters in the ranges 470-590, 590-850 and 850-1200 µm. Rat bone marrow stem cells differentiated into osteoblasts were cultured on the scaffolds for up to 10 days to evaluate cell growth, alkaline phosphatase (ALP) activity and the gene expression of the osteoblast markers RUNX2, OSX, COL, MSX2, ALP, OC and BSP by real-time PCR. Scaffolds were implanted in critical size rat calvarial defects for 2, 4, and 8 weeks for histomorphometric analysis. Cell growth and ALP activity were not affected by the pore size; however, there was an increase in the gene expression of osteoblastic markers with the increase in the pore sizes. At 2 weeks all scaffolds displayed a similar amount of bone and blood vessels formation. At 4 and 8 weeks much more bone formation and an increased number of blood vessels were observed in scaffolds with pores of 470-590 µm. These results show that PLGA-CaP is a promising biomaterial for bone engineering. However, ideally, combinations of larger (-1000 µm) and smaller (-500 µm) pores in a single scaffold would optimize cellular and tissue responses during bone healing.
authors: Cell Culture Laboratory, School of Dentistry of Ribeirao Preto, University of Sao Paulo, Brazil.
authors: Luciana Gonçalves
authors: LG
authors: Sicchieri
authors: Grasiele Edilaine
authors: GE
authors: Crippa
authors: Paulo Tambasco
authors: PT
authors: de Oliveira
authors: Marcio Mateus
authors: MM
authors: Beloti
authors: Adalberto Luiz
authors: AL
authors: Rosa
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001842:Bone and Bones / Q000187:drug effects* / Q000502:physiology; D002130:Calcium Phosphates / Q000494:pharmacology*; D002450:Cell Communication / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects; D019344:Lactic Acid / Q000494:pharmacology*; D008297:Male; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000166:cytology* / Q000201:enzymology; D010012:Osteogenesis / Q000187:drug effects; D011100:Polyglycolic Acid / Q000494:pharmacology*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D016062:Porosity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012886:Skull / Q000098:blood supply / Q000187:drug effects / Q000473:pathology; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D002130:Calcium Phosphates; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C020243:calcium phosphate; D000469:Alkaline Phosphatase