ABSTRACT
The development of an effective scaffold for bone defect repair is an urgent clinical need. However, it is challenging to design a scaffold with efficient osteoinduction and antimicrobial activity for regeneration of bone defect. In this study, we successfully prepared a hydroxyapatite (HA) porous scaffold with a surface-specific binding of peptides during osteoinduction and antimicrobial activity using a three-dimensional (3D) printing technology. The HA binding domain (HABD) was introduced to the C-terminal of bone morphogenetic protein 2 mimetic peptide (BMP2-MP) and antimicrobial peptide of PSI10. The binding capability results showed that BMP2-MP and PSI10-containing HABD were firmly bound to the surface of HA scaffolds. After BMP2-MP and PSI10 were bound to the scaffold surface, no negative effect was observed on cell proliferation and adhesion. The gene expression and protein translation levels of type I collagen (COL-I), osteocalcin (OCN) and Runx2 have been significantly improved in the BMP2-MP/HABP group. The level of alkaline phosphatase significantly increased in the BMP2-MP/HABP group. The inhibition zone test against Staphylococcus aureus and Escherichia coli BL21 prove that the PSI10/HABP@HA scaffold has strong antibacterial ability than another group. These findings suggest that 3D-printed HA scaffolds with efficient osteoinduction and antimicrobial activity represent a promising biomaterial for bone defect reconstruction.
ABSTRACT
AIM:To study the changes of ?-adrenoceptors in peripheral lymphocytes at different stages of asthma. METHODS:?-adrenoceptors in peripheral lymphocytes, cAMP and cGMP levels in blood plasma were measured by radioligand binding assay and radioimmunoassay.RESULTS:Bmax and Kd of ?-adrenoceptors in asthma at remission stage were markedly higher than that in normal subjects, while cAMP levels in blood plasma were not different between them. Bmax of ?-adrenoceptors and cAMP levels in blood plasma in asthma at acute exacerbation stage were significantly lower than that in normal subjects, Kds between these two groups were not much different. There was no correlation between ?-adrenoceptors, cAMP and cGMP levels in blood plasma and ventilatory functions.CONCLUSIONS:Changes of ?-adrenoceptors in asthma rather be a pathological change accompanied by the course of the disease than a primary defect.