티타늄과 니켈ᅳ티타늄 합금의 입자들이 생쥐의 복강내 대식세포에 미치는 영향

EFFECT OF TITANIUM AND NICKEL-TITANIUM PARTICLES ON MOUSE PERITONEAL MACROPHAGES

Titanium has been widely used as an implant material but particles can be liberated from the surface of implant during function and they may be toxic to the adjacent tissue. Nickel - titanium(shape memory) alloy may be not suitable for implant material because of containing toxic nickel. This study was designed to evaluate the effect of particles of titanium and nickel - titanium (Ni-Ti) alloy on mouse peritoneal macrophages. The particle sizes were below 150 jum. Macrophages were cultured at a density of 2X106 cells ml-1 and particles were used at a concentration of 0.025, 0-05 and 0.1 mg m l 1 in Hanks balanced salt solution(HBSS). The cells and particles were incubated for a period of 6，12，24 and 48 hours at 37c respectively. Control group was cultured in the same way without particulate material. Biological effects of these materials were measured by the assay of two enzymes. Lactic dehydrogenase (LDH) released into the supernatant indicates a damage of cell membrane and decreased intracellular level of glucose - 6 - phosphate dehydrogenase(G6PD) indicates a lowered phagocytic activity of the cells. Morphological changes were judged by microscopic examination after staining with hematoxylin and eosin. The results were as follows ; 1. The increase of LDH release towards the end of the culture period was observed in the control and the test groups. The rates of LDH release in test groups, especially in Ni-Ti alloy, were greater than in the control group. Comparatively the LDH release was increased with concentrations in both test groups. But there were no significant differences between the control and the test groups, and in concentrations of the test groups (p)0 .05). 2. A little changes in the activity of G6PD were detected in the control and the test groups with increasing time. The activities of G6PD in tKe test groups were relatively lower than those in the control and were decreased with concentrations in both test groups. But there were no significant differences in the concentrations of the test groups(p〉0.05X). 3. On microscopic examination, it was observed that the macrophages were unaffected by both materials as compared with the control group, and that the cells phagocytosing the small particles of metals were increased in number with time. Some of the cells were degenerated in the control and the test groups at 48 hours. Although titanium and Ni - Ti alloy affected the permeability of the cell membranes and the phagocytic activity of the cells to some extent, they were relatively well tolerated under the test conditions described here. So they may be biocompatible and suitable for implant materials.