Influence Of Surface Modification Of Titanium On The OPG/RANKL MRNA Secretion And Expression Of MG-63 Human Osteoblast-like Cells

Objective:The purpose of the study was to investigate the effects of surface modification of titanium on bioactivity of MG-63 human osteoblast-like cells and to study the relationship between surface microtopography and OPG/RANKL mRNA regulation ofMG-63 human osteobiast-like cells. So provides more information of fundamental research concerning the interaction of titanium implant-bone interface and surface modidication of titanium implants.Materials and methods:1. Polish the pure titanium plates with Al₂O₃ paper-grinding, anodic oxidation and sandblasting and acid-basement,labeled as PT group,AO group and SB-AB group,respectively.Surface microtopography was observed by SEM and parameter Ra was measured by XP-2 .2. MG-63 osteoblast-like cells were sed on the experimental group and control group.The cells on the plates surfaces were collected at the second,forth,sixth and eighth day and then the OPGmRNA was quantified by RT-PCR and real time PCR. 3. MG-63 osteoblast-like cells were sed on the experimental group and control group.The cells on the plates surfaces were collected at the second,forth,sixth and eighth day and then the RANKLmRNA was quantified by RT-PCR and real time PCR.Results:1.Ttitanium plates demonstrate different surface microtopography. PT group reveal grooves with the same direction;AO group contain a well-proportioned and honeycombed surface with the diameter about l-3um;SB-AB group have a multiporous and tatinum-gel layer with the diameter about 5-10um.Parameter Ra values are as follows:SB-AB group(Ra=3.4um)>PT group>AO group.2. MG-63 cells co-coltured with modified titanium plates can secret OPGmRNA and the quantity of the OPGmRNA is surface-specific and time-dependent. The OPGmRNA is sensitive to the surface microphotography. The expression of the OPGmRNA is up-regulated on the SB-AB group and AO group .The relation of the OPGmRNA and time is positive.Even surface microtopography and time are mutual,which can upregulate the OPGmRNA synergistically.3. MG-63 cells,co-cultured with the modified titanium plates can produce RANKLmRNA.The quantity of RANKLmRNA are more on the SB-AB group and PT group than the AO group and control group.The maximum is at the sixth day.Concultion:1 .Different surface modifications creat different microtopography of tatinium plates.PT group characterized by mechanical grooves with the same direction.AO group characterized by a well-proportioned and honeycombed surface and SB-AB group by a multiporous and tatinum-gel layer. 2. Expression of the OPGmRNA is surface-dependent and time-dependent. Certain microgrough surface and time can upregulate the OPGmRNA synergistically.3. Expression of the RANKLmRNA is related to the surface roughness. High roughness may upregulate the RANKLmRNA. RANKLmRNA is lower when time goes. Thus the ratio OPG/RANKL is up-regulated respectively and osteogenesis may occour.