The additive effects of photobiomodulation and bioactive glasses on enhancing early angiogenesis.

Bioactive glasses (BG) have been widely utilized as a biomaterial for bone repair. However, the early angiogenesis of BG may be inadequate, which weakens its osteogenic effects in large-sized bone defects and often leads to the failure of bone regeneration. In this study, we explored the effects of photobiomodulation (PBM) combined with BG on early angiogenesis to solve this bottleneck problem of insufficient early angiogenesis.In vitro, human umbilical vein endothelial cells (HUVECs) were cultured with BG extracts and treated with PBM using 1 J cm-2. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) and tubule formation assay were utilized to detect HUVECs' proliferation, vascular growth factor genes expression and tubules formation.In vivo, bone defects at the femoral metaphysis in Sprague-Dawley rats were treated with BG particulates and PBM at 120 J cm-2. Hematoxylin-eosin staining was used to observe the inflammatory response, tissue formation and biomaterial absorption of bone defects. Immunohistochemical staining was applied to observe the vascular-like structure formation. Thein vitroresults showed that PBM combined with BG significantly promoted HUVECs' proliferation, genes expression and mature tubules formation. On days 2, 4 and 7, the mRNA expression of VEGF in BG + PBM group was 2.70-, 2.59- and 3.05-fold higher than control (P< 0.05), and significantly higher than PBM and BG groups (P< 0.05). On days 4 and 7, the bFGF gene expression in BG + PBM group was 2.42- and 1.82-fold higher than control (P< 0.05), and also higher than PBM and BG groups (P< 0.05). Tube formation assay showed that mature tubules were formed in BG + PBM and PBM groups after 4 h, and the number in BG + PBM group was significantly higher than other groups (P< 0.05).In vivoresults further confirmed PBM induced early angiogenesis, with more vascular-like structures observed in BG + PBM and PBM groups 2 week post-surgery. With the optimum PBM fluence and BG concentration, PBM combined with BG exerted additive effects on enhancing early angiogenesis.

Antifungal drug susceptibility of oral Candida albicans isolates may be associated with apoptotic responses to Amphotericin B.

BACKGROUND: Candida albicans is the important opportunistic fungal pathogens which can cause oral Candidiasis and even more seriously systemic infection. Apoptosis of C. albicans induced by environmental factor such as weak acid and antifungal drugs were studied recently. Illustrating the phenomenon of apoptosis in C. albicans may help us to discover new antifungal therapy by activating the fungal cells to suicide. METHODS: Two oral C. albians clinical isolates which isolated respectively from healthy host [Strain 23C: minimal inhibition concentration (MIC) is 0.125 microg/ml for Amphotericin B (AmB)] and advanced cancer patient (Strain 28A: MIC is 2 microg/ml for AmB), were induced by 1 microg/ml AmB in vitro for 200 min, and then studied the apoptosis markers using terminal deoxynucletidyltransferase-mediated dUTP nick end labeling (TUNEL) (shown by diaminobenzidine and fluorescent isothiocyanate), and the ultrastructure of cell nuclear using transmission electron microscope (TEM), quantitative analysis using flow cytometry for the rapid exposure of phosphatidylserine at the outer membrane and propodium iodide (PI) double staining. C. albicans conference strain YEM30 was used as the control strain. RESULTS: With TUNEL assay and TEM, we detected the typical characteristics of apoptosis. Strain 23C (with low MIC) showed significantly higher percentage of apoptosis (19.92%) compared with Strain 28A (with high MIC) which was isolated from the cancer patient (7.29%) (P < 0.01). In addition, 7.3% of early apoptosis cells of Strain 23C can form colonies on the plates, while 15% for Strain 28A. None of the PI+ cells can form colony. CONCLUSIONS: Apoptosis of oral C. albicans isolates can be induced by AmB. The feature of antifungal drug susceptibility of the oral C. albicans clinical isolates may associate with the response of apoptosis inducing.