BONE CELL BEHAVIOR ON MATRIGEL(R)-COATED CA P COATINGS OF VARYING CRYSTALLINITIES/

Rat calvarial cell mitogenic behavior was investigated on various biom aterials coated with Matrigel(R), a basement membrane matrix containin g growth factors. Low (20-40%) and high (70-90%) crystallinity hydroxy apatite (rHA and cHA), rough titanium (Ti), and tissue culture polysty rene (TP) surfaces were compared. Surface chemistry and calcium resorp tion of HA coatings, alkaline phosphatase activity (APA), and growth o f cells were measured for Matrigel(R)-coated and uncoated surfaces at 2, 7, and 14 days. Gene expression for four noncollagenous bone-relate d proteins (osteonectin, osteopontin, alkaline phosphatase, and osteoc alcin) was also investigated by reverse transcription and polymerase c hain reaction up to 28 days. Ca concentration in incubating solutions increased with time for the two types of HA coatings and was always gr eater for rHA than cHA. Surface chemistry and coating dissolution rate s were not affected by the presence of Matrigel(R) or cells throughout the study. APA of cells on the two HA-coated surfaces was comparably enhanced in the presence of Matrigel(R) and was greater than on Ti sur faces. Only HA surfaces showed an increased APA of cells with time in the presence of Matrigel(R). Cell growth peaked at 7 days and was grea test for cells on the two HA surfaces and without Matrigel(R). At 14 d ays, cell growth was comparable on the four surfaces. The presence of HA and Matrigel(R) enhanced cell-specific APA at 14 days. Gene express ion for all four proteins investigated showed no differences between s urfaces after 7 days. At 2 and 7 days,gene expression was indicative o f proliferation for Ti, and of proliferation, differentiation, and min eralization for HA and TP more so without Matrigel(R). The addition of this matrix significantly enhanced mitogenicity of calvarial cells on HA only after 14 days. Matrigel(R) eliminated differences seen betwee n the two HA coatings. Gene expression was not enhanced or inhibited b y the presence of Matrigel(R). (C) 1998 John Wiley & Sons, Inc.