Abstract:Aim To explore the controlled release effect of the recombinant Ephrin-b2/Fc chimera from self assembling peptide of RAD16-Ⅱ and the immunogenicity of RAD16-Ⅱ. Take RAD16-Ⅱas a delivery vehicle to prevent the ungroomed Ephrin-b2/Fc protein from being degraded in vivo and increase therapeutic effect. Methods The moulding of the oligopeptide was observed by macroscopy and microscopy. The releasing effect was assayed by releasing curve obtained from test in vitro. In vivo, Sprague-Dawley rats were prepared to acute myocardial infarction models by ligation of the left anterior descending branch. The survival rats were divided into 2 groups and separately intra myocardially injected recombinant Ephrin-b2/Fc proteins(E group,n25) and sapeptide- Ephrin-b2/Fc protein complex(ES group,n25). At set time(1 h,3 h,24 h,7 d,14 d),the samples of the myocardial tissue and sera were collected and respectively used for immunofluorescence and westernblot to determine the remaining or losing of the protein. RAD16-Ⅱ solution was administrated through subcutaneous injection. 5 weeks later, the titer of anti-sapeptide in serum was assayed by ELISA. Results It is observed that RAD16-Ⅱsolution can self-assemble into nanofibers which fabricate net structure in condition of PBS. Within net structure, the releasing duration of chimeric Ephrin-b2/Fc lasted up to 144 h and more than 50% mass was released in 120 h. As shown in immunofluorescence, the retention duration of the chimeric protein in ES group was significantly longer than that in E group at the same time(P<0.05). And westernbolt also demonstrated the amount of protein releasly into blood in ES group was less significant than that in E group(P<0.05). The titer of the antibody was not significantly different from RAD16-Ⅱ administration to negative control group, which showed that RAD16-Ⅱ would not trigger immune response. Conclusion RAD16-Ⅱ oligopeptide can postpone the release of chimeric Ephrin-b2/Fc both in vivo and in vitro. It is a relatively reliable and safe biomaterial delivery vehicle of Ephrin-b2/Fc protein in myocardial infarction and ischemia research.