title: Effect of hydroxyapatite microcrystals on macrophage activity.
abstract: Hydroxyapatite (HAp) microcrystals were synthesized by a neutralization reaction of Ca(OH)2 suspension and H3PO4 solution using an ultrasonic homogenizer. The in vitro interaction of HAp microcrystals with rat peritoneal macrophages was investigated by measuring the viability, acid phosphatase (ACP) activity, lactate dehydrogenase (LDH) activity and intracellular calcium content. HAp calcined at 800 degrees C and alpha-alumina particles (alumina) were used as comparative materials. Macrophages actively phagocytosed HAp microcrystals by dissolving them. However, no damage in macrophages exposed to HAp microcrystals was observed by transmission electron microscopy. Macrophages in the presence of HAp microcrystals showed less ACP and LDH activity and higher intracellular calcium content than those in the presence of calcined HAp and alumina. HAp microcrystals had excellent biocompatibility to macrophages as well as sintered HAp.
authors.affiliation: Division of Inorganic Materials, Tokyo Medical and Dental University, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Fukuchi
authors.forename: M
authors.initials: M
authors.lastname: Akao
authors.forename: A
authors.initials: A
authors.lastname: Sato
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000537:Aluminum Oxide / Q000494:pharmacology; D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002118:Calcium / Q000032:analysis; D002126:Calcium Hydroxide / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects; D003460:Crystallization; D017886:Durapatite / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D006358:Hot Temperature; D007424:Intracellular Fluid / Q000737:chemistry; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D008297:Male; D008854:Microscopy, Electron; D010587:Phagocytosis; D010756:Phosphoric Acids / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012995:Solubility
chemical_list: D001672:Biocompatible Materials; D010756:Phosphoric Acids; D017886:Durapatite; D007770:L-Lactate Dehydrogenase; D000135:Acid Phosphatase; D000537:Aluminum Oxide; D002126:Calcium Hydroxide; D002118:Calcium