Objective To review the latest research progress on keratinocyte growth factor (KGF), to thoroughlyunderstand its basic characteristics and appl ication methods and to lay a sol id foundation for the research and development of new KGF medicines and improving the qual ity of skin substitutes. Methods Domestical and international l iteratures on KGFin recent years were extensively reviewed and analyzed. Results KGF was secreted by mesenchymal cells and its receptors were distributed in epithel ium to promote the prol iferation, migration and differentiation of epithel ial cell specifically, which closely related to the organ development, wound heal ing, tumorigenesis and immune reconstruction. Conclusion KGF can be used to improve wound heal ing and the performance of skin substitutes. However, the structure of KGF needs to be changed to el iminate its side effects and purify its promoting effect on epithel ial cell growth.
To harvest human keratinocyte growth factor (KGF) mimic peptides with Ph.D.-7TM phage display peptide l ibrary. Methods Ph.D.-7TM phage display peptide l ibrary was biopanned for 4 rounds to harvest monoclonal anti-body human KGF and then phage tilter was detected. ELISA detection was performed to detect the binding force of random-selected monoclonal phages, thereafter DNA extracted from phages with better binding activity was sequenced and the Basic BLAST system was appl ied to conduct the sequence similarity and homology analysis. Results After 4 rounds ofbiopanning, the titer of phages was increased gradually and the enrichment of specific phage mimic peptides was obtained. The titers of monoclonal phages were up to 2.0 × 1014 pfu/mL according to ELISA detection. According to the absorbance value, the monoclonal phages with better binding activities to certain specific antibodies were sequenced, and 26 base sequences related to the promotion of division and growth were verified, 2 of which were similar to human KGF. Homology sequence analysis revealed that the common sequence of those 26 base sequences was similar to the partial sequences of human KGF. Conclusion The phage mimic peptides resembl ing or related to human KGF DNA can be harvested from Ph.D.-7TM phage display peptide l ibrary, which may be conducive to improve human KGF performance, wound heal ing and the qual ity of tissue engineered skin substitutes.
ObjectiveTo detect the difference in the osteogenesis ability of biphasic calcium phosphate (BCP) ceramic granular materials with different mesoporous diameters prepared at different sintering temperatures through in vivo and in vitro experiments, so as to provide evidence for screening BCP materials with better clinical application parameters.MethodsThree kinds of BCP (materials 1, 2, 3) were prepared by mixing hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) at a ratio of 8∶2 and sintered at 1 050, 1 150, and 1 250℃ for 3 hours, respectively. The internal porosity and the diameter, volume, and area of the mesopore were measured by Brunauer-Emmett-Teller test (BET); the composition of the material was evaluated by X-ray diffraction (XRD); the microscopic surface morphology of the material was observed by scanning electron microscopy (SEM). The 3rd generation bone marrow mesenchymal stem cells (BMSCs) from Sprague-Dawley rats were co-cultured with the materials 1, 2, and 3 for 7 days in vitro respectively (groups A, B, and C), and the cells adhesion on the materials was observed by SEM and phalloidine staining, respectively. Cell proliferation activity was measured by cell counting kit 8 method. In vivo, 9 muscle bags were made in dorsal muscles of 9 beagles, respectively. The muscle bags were randomly divided into 3 groups (3 per beagle in each group) and materials 1, 2, and 3 were placed into the muscle bags of groups A, B, and C, respectively. After 1, 2, and 3 months of operation, 3 beagles were anesthetized and the samples were stained with HE, Masson, and Safranin, and the bone formation area ratio in the BCP gap was calculated. Real-time fluorescence quantitative PCR (qRT-PCR) was performed to detect the expressions of bone-related genes [including alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OC)].ResultsThe BET test showed that with the increase of sintering temperature, the internal porosity of the particles did not change significantly, but the diameter, volume, and area of the mesopores gradually decreased. The XRD detection showed that the XRD waves of HA and β-TCP could be seen in all 3 kinds of materials; SEM showed that there were widely distributed macropores on the surface of 3 kinds of BCPs, and the interpores connected with the others. In vitro, BMSCs adhered and proliferated on the surfaces of 3 kinds of BCPs, and the cell biocompatibility of the materials in groups B and C was better than that in group A. In vivo, obvious osteoid tissue deposition could be observed in the intergranular space of 3 kinds of BCPs from 2 months after implantation. The bone formation area ratio of each group increased with time. The bone formation area ratio in group A was significantly higher than that in groups B and C at 2 and 3 months after implantation, and in group A than in group B at 1 month (P<0.05). qRT-PCR showed that the expressions of osteogenic related genes peaked at 2 months in group A, and gradually increased with time in groups B and C. The relative expressions of ALP and OPN mRNAs in group A were significantly higher than those in groups B and C at 1 month after implantation, the relative expression of OC mRNA in group A was significantly higher than that in groups B and C at 2 months after operation, the relative expression of ALP mRNA in groups B and C and the relative expression of OPN mRNA in group B were significantly higher than those in group A, all showing significant differences (P<0.05); there was no significant difference in the relative expression of each gene among the other groups at each time point (P>0.05).ConclusionThe mesoporous diameter of BCP decreases with the increase of sintering temperature. Different mesoporous diameters lead to different ectopic osteogenesis of BCP materials. BCP material with mesoporous diameter of 12.57 nm has better osteogenic ability which can activate the osteogenic gene earlier. The mesoporous diameter is expected to be an adjustable index for optimizing the osteogenic capacity of BCP materials.