The Effect On Osseointegration And The Expression Of OPG And RANKL By Nano Hydroxyapatite Modificated Titanium Surface

Objective:The purpose of this study was to observe the effect on osseointegration and the expression of OPG and RANKL by nano hydroxyapatite modificated titanium surface.In order to explore the effect of titanium implants modified by nHA promote the osseointegration.So as to provide some relevant research basis for clinical implant surface design.Methods:The health New Zealand rabbits(about june months old)were randomly divided into 3groups.Each rabbit adopted bilateral autologous control,in other words,the right femur lateral were implanted 1 experimental group(nHA)implant,the same part of the left were implanted 1 control group(Ti)implant.After surgery,the rabbits were sacrificed in 2 w、4w、8 w respectively,then get the samples about 15mm3,and were observed with the general observation,HE staining,Masson staining and immunohistochemical of OPG、RANKL which can detect the expression of OPG and RANKL in osseointegration process by MOD.The experimental date were analyzed by SPSS17.0,P < 0.05 thinks the difference was significant.Results:General observation: All the implants had good osseointegration and no loose phenomenon.There were no complications such as infection,fester and abnormal tissue around the implants.X-ray observation: After the implants were implanted in vivo,the range of the low density image in two groups was gradually decrease or disappear with the increase of time.But at 2 w and 4 w,the range of the low density image in experimental group peri-implant was less than control group.At 8 w,the bone density in two groups peri-implant compared with the normal bone density have no significant difference.HE staining: After the implants implant in vivo,the area of the newly formed bone and bone trabeculae in two groups peri-implant show an increasing trend.But at 2 w and 4w,Compared with the control group,the percentage of trabecular bone area in the experimental group was significantly higher than that in the control group,which indicated that nHA could promote the early osseointegration.At 8 w,the new bone was continuous red dye around the implant in two groups,the percentage of trabecular bone area in the two groups were very high,and there was no significant difference between the two groups,which indicated that the growth of new bone tissue reached a stable level at 8 w.Immunohistochemical of OPG、RANKL: The expression of RANKL and OPG can be detected in two groups.At 2 w、4 w、8 w,the experimental group and the control group RANKL,OPG values were compared separately,the differences were statistically significant.At 2 w and 4 w,the MOD(Mean optical density)values of RANKL of two groups were greater than the MOD of OPG,and the walues were in contrast to the results of 8w,which revealed the active degree of early osteoclastic was higher than that of late stage.At 2 w,the ratio of RANKL/OPG in experimental group was greater than that in the control group,and the difference was statistically significant.The results showed that the osteoclast of the experimental group was more active in the early stage.At 4 w,the ratio of RANKL/OPG in the experimental group was less than that in the control group,and the difference was statistically significant,which showed that the activity of osteoclasts of the experimental group was decrease.At 8 w,the ratio of RANKL/OPG in the experimental group was slightly smaller than the control group,the difference was not statistically significant,the results showed that there was no significant difference between the two groups about the activity of osteoclasts at the late stage.Conclusion:nHA implanted in bone is of good biocompatibility and can promote early osseointegration.Both RANKL and OPG protein were expressed in the process osseointegration,and the change of RANKL/OPG ratio was consistent with the osseointegration process,It is suggested that nHA modification of titanium implants can promote the early osseointegration may be related to the promotion of the formation and differentiation of osteoclasts in osseointegration process.