| Objective: The objective of the research was to prepare recombinant human like collagen based-bone materials and to carry on biological activity processing, which avoid virus-danger of animal-sourced collagen. Furthermore, improve the biocompatibility and inductivity of the scaffold materials. Obtain the novel bone repair material which has a promising broad market. Study the cicatrisation process and the effect on rabbit radius damage. The main purpose of this experiment was to give preliminary experimental evidence and to prove the novel composites as potential bone substitutions or bone tissue engineering scaffold.Methods: 1. Preparation of materials: the material was manufactured in biomaterial group lab of Tsinghua University. This composite was compounded by electrostatic self-assembly recombinant human like collagen and nano-hydroxyapatite (n-HA). Its characteristics included biodegradable, nontoxic, nonhemolysis, nonpyrogen that had been confirmed in the experiments of acute toxicity, pyrogen, hemolysis etc. It had right biological characteristics which met the basic conditions demand in bone tissue engineering. After preparation, the physical and chemical properties of the composites were studied.2. Cell experiment: Planted the same density of MC3T3E1 cells into these materials separately. P: PLA group; PN: recombinant human like collagen/ nano-hydroxyapatite group; PNA: recombinant human like collagen/ nano- hydroxyapatite/AsAP-Dex group; PNJ: electrostatic self-assembly of recombinant human like collagen/nano-hydroxyapatite group; PNAJ: electrostatic self-assembly of recombinant human like collagen/ nano-hydroxyapatite/ AsAP-Dex group. MTT (methyl thiazolyl tetrazolium) assay, the scanning electronic microscope observation and the laser scanning confocal microscopy observation was carried on at the first, fourth, seventh day.3. Animal experiments: We made 45 adult rabbits solo right radial bone defect, and planted these 5 type materials respectively. These rabbit were divided into 5 groups randomly: After the fourth, eighth and twelfth weeks, the experiment rabbits were analyzed by radiographic, the animals of every group were killed according to different operation period and the implantations were taken off, studied by gross observation, X-ray density and histological analysis.Results:①P,PN,PNA,PNJ,PNAJ groups all have porous characteristic, the aperture can reach 100-300μm. The surface of PNJ,PNAJ group materials were succeeded electrostatic self-assembly by recombinant human like collagen. Recombinant human like collagen based bone-materials reserved the component choiceness characteristic of animal-sourced collagen based bone materials.②cell experiment indicated that MTT assay of PN,PNA group preceded P,PNJ,PNAJ group, and the difference had exponential correlation.③Animal experiment displayed that 12 weeks after operation, the PN,PNA groups restore the wane completely, and their were better than that in other group, in every period by X-ray evaluation.Conclusions: We used biological bionics mineralization recombinant human like collagen replaces the natural animal collagen to prepare the new bone repair frame material for the first time. Through cell experiment in vitro and animal experimentation in vivo, the result proved that this material had good biological compatibility and bone conduction. The recombinant human like collagen could avoid the virus danger of animal collagen, enable the material to have a higher safety performance, become optimal bone repaired material.
|
PDF Full Text Request