The fate of biodegradable microspheres injected into rat brain.
Biodegradable microspheres made with poly-[D,L-lactide-co-glycolide] represent an evolving technology for drug delivery into the central nervous system. Even though these microspheres have been shown to be engulfed by astrocytes in vitro, the purpose of the present study was to track the fate of biodegradable microspheres in vivo. This was accomplished using microspheres containing the fluorescent dye coumarin-6 followed 1 day, 1 week and 1 month after intracerebral injections of this material were made into the rat brain. Using dual color immunohistochemistry and antisera against glial fibrillary acidic protein for astrocytes versus phosphotyrosine for microglia, results demonstrate that phagocytosis of small coumarin-containing microspheres <7.5 microm in diameter was primarily by microglia in vivo during the first week post-injection. In contrast, only a small minority of these microspheres appeared to be engulfed by astrocytes.
Nicholas
Anthony P
AP
Department of Neurology, University of Alabama at Birmingham and the Birmingham Veterans Administration Medical Center, 619 19th Street South, Birmingham, AL 35249-7340, USA. tony@email.neuro.uab.edu
McInnis
Carey
C
Gupta
Kiran B
KB
Snow
William W
WW
Love
Darryl F
DF
Mason
David W
DW
Ferrell
Teresa M
TM
Staas
Jay K
JK
Tice
Thomas R
TR
D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001672:Biocompatible Materials / Q000008:administration & dosage / Q000493:pharmacokinetics; D001921:Brain / Q000378:metabolism*; D007276:Injections, Intraventricular; D019344:Lactic Acid / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D008297:Male; D008863:Microspheres; D011100:Polyglycolic Acid / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley
D001672:Biocompatible Materials; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid