Preparations Of RhIGF-I-loaded Gelatin Microspheres And Effects Of RhIGF-I-GMs On Human Periodontal Ligament Fibroblasts In Vitro

Objective:To prepare rhIGF-Ⅰ-loaded gelatin microspheres(rhIGF-Ⅰ-GMs) and investigate their general properties, in vitro drug release characteristics and evaluate the biological effects of rhIGF-Ⅰ-GMs on the proliferation and collagenⅠtype in human periodontal ligament fibroblasts(HPDLFs).In order to investigate the sustained released characteristics of rhIGF-Ⅰ-GMs and the effect on HPDLFs in timly and concentrain-related manner.It can provide us another way of cytokine sustained releasing in periodontal tissue engineering.Method:HPDLFs were cultured and identified in vitro.The rhIGF-I-loaded gelatin microspheres were prepared by improved emulsified cold-condensation method. Their general properties were observed by SEM. To measure the content of rhIGF-I-GMs by ELISA method to study their release characteristics in tivro. Three groups are differentiated:the group of rhIGF-I-GMs,five differents concentrations(0μg/L,g/L,10μg/L,50μg/L,100μg/L) of rhIGF-I that contained in GMs.the group of rhIGF-I, five differents concentrations (Oug/L, 1μg/L,10μg/L,50μg/L,100μg/L) of rhIGF-Ⅰ.The goup of GMs that contained nothing,were used to intervene normal periodontal ligament cells. The proliferation of the cultured fibroblast was measured with MTT method and collagen type I was measured with hydroxyprolline kit after rhIGF-Ⅰ-GMs and rhIGF-Ⅰbeing added to the DMEM culture medium.Results:The rhIGF-Ⅰ-GMs were good, even and uniform spheres with mean particle size of (12.51±3.53)μm. The lyophilized powder was pure white with good disparity. The drug loading amount and encapsulation efficiency of rhIGF-Ⅰ-GMs were 920ng/g and 92.0%. The drug release rate was 72.5% at the 7th days after plate culturing. HPDLFs were good culthuerd. Both rhIGF-Iand rhIGF-Ⅰ-GMs promoted the proliferation and collagenⅠtype of HPDLFs in a concentration and time related manner.Singnificantly greater proliferation and expression were found in rhIGF-Ⅰ-GMs group.Conclusion:The rhIGF-Ⅰ-GMs and their lyophilized powder have excellent pharmaceutical properties. The rhIGF-Ⅰ-GMs can significantly promote the proliferation and increase collagen typeⅠof HPDLFs by sustained release rhIGF-Ⅰ.