a b s t r a c tA challenge in using bioactive melt-derived glass in bone regeneration is to produce scaffolds with interconnected pores while maintaining the amorphous nature of the glass and its associated bioactivity. Here we introduce a method for creating porous melt-derived bioactive glass foam scaffolds with low silica content and report in vitro and preliminary in vivo data. The gel-cast foaming process was adapted, employing temperature controlled gelation of gelatin, rather than the in situ acrylic polymerisation used previously. To form a 3D construct from melt derived glasses, particles must be fused via thermal processing, termed sintering. The original Bioglass Ò 45S5 composition crystallises upon sintering, altering its bioactivity, due to the temperature difference between the glass transition temperature and the crystallisation onset being small. Here, we optimised and compared scaffolds from three glass compositions, ICIE16, PSrBG and 13-93, which were selected due to their widened sintering windows. Amorphous scaffolds with modal pore interconnect diameters between 100-150 mm and porosities of 75% had compressive strengths of 3.4 ± 0.3 MPa, 8.4 ± 0.8 MPa and 15.3 ± 1.8 MPa, for ICIE16, PSrBG and 13-93 respectively. These porosities and compressive strength values are within the range of cancellous bone, and greater than previously reported foamed scaffolds. Dental pulp stem cells attached to the scaffold surfaces during in vitro culture and were viable. In vivo, the scaffolds were found to regenerate bone in a rabbit model according to X-ray micro tomography imaging. Statement of SignificanceThis manuscript describes a new method for making scaffolds from bioactive glasses using highly bioactive glass compositions. The glass compositions have lower silica content that those that have been previously made into amorphous scaffolds and they have been designed to have similar network connectivity to that of the original (and commercially used) 45S5 Bioglass. The aim was to match Bioglass' bioactivity. The scaffolds retain the amorphous nature of bioactive glass while having an open pore structure and compressive strength similar to porous bone (the original 45S5 Bioglass crystallises during sintering, which can cause reduced bioactivity or instability).The new scaffolds showed unexpectedly rapid bone regeneration in a rabbit model.
Polycystic ovary syndrome (PCOS) is associated with low-quality oocytes. The aim of the present study was to investigate the effects of metformin (MET), N-acetylcysteine (NAC) and their combination on follicular fluid parameters, oocytes and embryo quality in PCOS patients. A prospective randomised placebo-controlled pilot study on 60 Iranian women with PCOS (aged 25-35 years) undergoing intracytoplasmic sperm injection (ICSI) was designed. Women were divided into four groups (n=15 in each): (1) an MET, administered 1500mg day(-1) MET; (2) an NAC group, administered 1800mg day(-1) NAC; (3) an NAC + MET group; and (4) a placebo group. Drugs were administered from the 3rd day of previous cycle until the day of oocyte aspiration (6 weeks treatment in total). Data were analysed by one-way ANOVA, with significance set at P<0.05. The number of immature and abnormal oocytes decreased significantly in the NAC compared with placebo group, with a concomitant increase in the number of good-quality embryos in the NAC group (P<0.05). Malondialdehyde levels decreased significantly in the NAC and NAC + MET groups compared with the placebo-treated group (P<0.02). In addition, there were significant decreases in leptin levels in the NAC, MET and NAC + MET groups compared with the placebo group (P<0.001). Insulin and LH levels were significantly lower in the MET and NAC groups compared with the placebo-treated group (P<0.02). We concluded that NAC improves oocyte and embryo quality and could be administered as an alternative to MET.
In relation to the growing recent interest in the establishment of sperm-mediated gene transfer (SMGT) technology as a convenient and effective method for the simple production of transgenic animals, in this study the possibility of using SMGT to produce transgenic caprine embryos was investigated for the first time. Buck sperm were directly incubated with different concentrations (0-500 ng) of pcDNA/his/Lac-Z plasmid and used for IVF or ICSI. Sperm used for ICSI were categorized into motile or live-immotile group before being injected into oocytes. In a separate experiment, dead sperm prepared by repeated freezing/thawing were used for DNA-incubation before ICSI. Sham injection was carried out by intracytoplasmic injection of approximately the same volume of media containing different doses of DNA using an ICSI needle. Transgene expression and transmission were detected by X-Gal staining and PCR analysis of developed embryos, respectively. A reasonable blastocyst rate was observed in all the groups. Only embryos in the sham group were negative for transgene transmission. Transgene expression was completely dependent on the delivery technique and status of sperm, and was only observed in the live-immotile and dead ICSI groups. The results of this study showed that the technique (IVF vs. ICSI vs. sham injection), sperm status (motile vs. live-immotile vs. dead) and to some extent DNA concentration affect embryo development, transgene transmission and expression.
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