Effects Of RGD Peptide Modified SLA Titanium Discs On Osseointegration In Diabetic Mini-Pigs

[Objective]The aim of this research was to observe whether the modified Sandblasted and Acid-etched (SLA) surface titanium discs by the immobilized Arg-Gly-Asp (RGD) peptide via chemical grafting methods could promote the osseointegration on a diabetic Guangxi BA-MA mini-pig model.[Methods]Five Guangxi BA-MA Mini-Pigs were used for this research. Three of them were randomly induced into diabetes models by using streptozotocin (STZ), and the other two pigs were set as a control group. RGD peptite was grafted on the SLA surface of titanium implant discs by chemical coupling method. Each Mini-Pig was implanted separately 3 SLA titanium discs and 3 SLA/RGD titanium discs (discs diameter=5mm) at Maxillae,. All animals were sacrificed at one month. Samples were then fixed by 4% formaldehyde and analyzed by using Micro-CT and undecalcified histology methods.[Results]There were no significant differences with the parameters of bone mineral density(BMD), bone trabecular thickness(Th.Th), trabecular number(Th.N), and trabecular spacing(Th.Sp) when non-diabetes SLA (NDM-SLA) compared with non-diabetes SLA/RGD (NDM-SLA/RGD) group, non-diabetes SLA (NDM-SLA) compared with diabetes SLA (DM-SLA) group, diabetes SLA (DM-SLA) compared with diabetes SLA/RGD (DM-SLA/RGD) group, and non-diabetes SLA/RGD (NDM-SLA/RGD) compared with diabetes SLA/RGD (DM-SLA/RGD) group. Resin embedded tissue histological analysis showed the bone to implant contact (BIC) value of RGD peptide modified SLA titanium discs in NDM group are significant higher than DM group (P<,0.05). In NDM group, the BIC value of RGD modified SLA titanium discs are also significant higher than normal SLA titanium discs (P<0.05). No significant differences were found when NDM-SLA compared with DM-SLA group, and DM-SLA group and DM-SLA/RGD group, and (p>0.05).[Conclusion]RGD peptide modified SLA titanium discs obviously promoted bone to implant contact; The diabetes models didn’t show negative effects on the osseointegration of SLA titanium discs when compared with NDM pigs. However, when the SLA discs were modified by RGD peptide, RGD obvious improved bone formation around implants in NDM group when compared with DM group, which implies DM may inhibit the effects of RGD. This study was supported by the Fundamental Research Funds for the Tertiary Education (021414310017), Key Project of Science and Technology Bureau of Jiangsu Province (BL2013002), The High Level Talent Selection and Training Project of "The Top Six Talents" in Jiangsu Province(2013-SWYY-006) and Second Level of Nanjing Training Project for the Young talents in the health area(2012-B2-226).