title: In vivo biocompatibility studies of poly(D,L-lactide)/poly(ethylene glycol)-poly(L-lactide) microspheres containing all-trans-retinoic acid.
abstract: Biocompatibility studies of all-trans-retinoic acid (RA)-loaded microspheres were carried out after they were subcutaneously injected into rats. To characterize the inflammatory response to these microspheres, tissue reactions at the implantation site and cell types in the interstices of the microspheres were evaluated for 180 days. On the 15th day, the cross-sectional area of the fibrous capsules surrounding the implantation site of the RA-loaded microspheres was four times larger than that of the control microspheres. The size of the fibrous capsules surrounding the implantation site of the RA-loaded microspheres decreased significantly over a period of 75 days, while the size of the fibrous capsules surrounding the implantation site of the control microspheres remained almost constant throughout the entire course of 180 days. The tissue response to the RA-loaded microspheres was more intensified by the increased extensive cellular infiltration of macrophages, granulation tissue, and fibrosis than that to the control microspheres. The difference in the inflammatory response between the RA-loaded microspheres and the control microspheres was significant for 75 days after implantation. It was suggested that the released RA from the microspheres stimulated inflammatory responses. However, no further enhanced inflammation reactions were detected after RA had been completely released from the microspheres.
authors.affiliation: Department of Materials Science and Engineering, Kwangju Institute of Science and Technology, Gwangju, Korea.
authors.forename: Yongdoo
authors.initials: Y
authors.lastname: Choi
authors.forename: Sang Yoon
authors.initials: SY
authors.lastname: Kim
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Kim
authors.forename: Tae Gwan
authors.initials: TG
authors.lastname: Park
authors.forename: Hyun Tae
authors.initials: HT
authors.lastname: Moon
authors.forename: Youngro
authors.initials: Y
authors.lastname: Byun
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D016503:Drug Delivery Systems / Q000009:adverse effects / Q000379:methods*; D005260:Female; D005355:Fibrosis / Q000139:chemically induced / Q000473:pathology; D006097:Granulation Tissue / Q000187:drug effects / Q000473:pathology; D007249:Inflammation / Q000139:chemically induced / Q000473:pathology; D007279:Injections, Subcutaneous; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D008422:Materials Testing; D008863:Microspheres; D011091:Polyesters / Q000008:administration & dosage* / Q000633:toxicity; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000633:toxicity; D051381:Rats; D014212:Tretinoin / Q000008:administration & dosage*
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011092:Polyethylene Glycols; C033616:poly(lactide); D014212:Tretinoin; C083464:poly(ethyleneglycol-lactide)