[Influence of dosage on cell biocompatibility of hydroxyapatite/tricalcium phosphate].
OBJECTIVE
To investigate the influence of different dose levels of hydroxyapatite/tricalcium phosphate (HA/TCP) on the proliferation and alkaline phosphatase (ALP) activity of rabbit osteoblasts.


METHODS
Three different dose levels of HA/TCP (10%, 40%, 70%) were co-cultivated with rabbit osteoblasts respectively. The proliferation and ALP expression capacity of osteoblasts were examined with MTT method and enzyme histochemistry once every 24 hours until 5 days. Three control groups of other materials were treated and examined in the same way: rabbit osteoblasts as normal control; polyvinylchloride as positive control; titanium alloy as negative control.


RESULTS
There was remarkable time-effect relationship in the proliferation of osteoblasts. Ten percent HA/TCP did not affect osteoblasts growth while 40% HA/TCP could slow the cell growth rate down though time-effect relationship still existed. The proliferation of osteoblasts stagnated when co-cultivated with 70% HA/TCP. On the other hand, 10% HA/TCP could cause reversible damage on ALP activity of osteoblasts, whereas when the dose was 40%, and the cultivation lasted 6 days the damage was irreversible. Three different dose levels of titanium alloy (10%, 40%, 70%) had no effect on the proliferation or ALP activity of osteoblasts.


CONCLUSIONS
Dosage is an important factor affecting the biocompatibility evaluation of biomaterial. It suggests that dose choosing should be more specified upon each individual biomaterial. It also indicates that ALP may be a good supplementary index of the cell compatibility of material.
Zhang
Zhen
Z
Laboratory of Transplant Engineering and Transplant Immunology, West China Hospital, Sichuan University, Chengdu, Sichuan, P. R. China 610041.
Lu
Xiao-Feng
XF
Wang
Zhi-Ming
ZM
Lu
Bing
B
Cheng
Jing-Qiu
JQ
Li
You-Ping
YP
D000818:Animals; D018786:Bone Substitutes; D002130:Calcium Phosphates / Q000008:administration & dosage* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006882:Hydroxyapatites / Q000008:administration & dosage* / Q000494:pharmacology; D066298:In Vitro Techniques; D010006:Osteoblasts / Q000187:drug effects* / Q000502:physiology; D011817:Rabbits
D018786:Bone Substitutes; D002130:Calcium Phosphates; D006882:Hydroxyapatites; C485817:beta-tricalcium phosphate; C018392:tricalcium phosphate