Effects of polydopamine-coated porous titanium alloy scaffolds loaded with zoledronic acid-gelatin nanoparticles for topical sustained drug release on osteoclasts: an in vitro study / 中华创伤骨科杂志

Objective:To analyze the effects of a novel type of polydopamine (PDA)-coated porous titanium alloy scaffolds loaded with zoledronic acid-gelatin nanoparticles (ZOL-GNPs) for topical sustained drug release on osteoclasts in vitro. Methods:After porous titanium alloy scaffolds were fabricated using electron beam melting technique and ZOL-GNPs with different ZOL concentrations (0, 1, 10, 50, 100, 500 μmol/L) were prepared by desolvation method, PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs were constructed by combining the two. The characteristics of the scaffolds were analyzed. The biomechanics of 3 different scaffolds (bare porous titanium alloy scaffolds, PDA-coated porous titanium alloy scaffolds, and PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs) were investigated. Drug release detection was carried out by high performance liquid chromatography on the 1st, 4th, 7th, 14th, 21st, and 28th days respectively. The osteoclasts were inoculated into the novel scaffolds with different ZOL concentrations. The expression of osteoclast-related genes was detected by real-time quantitative (RT)-polymerase chain reaction (PCR); the expression of osteoclast-related proteins was detected by Western-blot.Results:The PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs were successfully constructed. Electron microscope scanning showed that the GNPs were well spheroidized, smooth in surface, and uniformly dispersed, with a particle size of (243.6±63.4) nm. The ZOL-GNPs were uniformly compounded on the surface and in the pores of the scaffolds, and the spheres were regular in shape with no adhesion. The biomechanical experiments showed that the elastic moduli of the porous titanium alloy scaffolds under 3 different conditions were (1.81±0.12) GPa, (1.80±0.23) GPa and (1.81±0.15) GPa, showing no significant difference ( P> 0.05). The drug release percentage in the porous titanium alloy scaffolds was obviously high on the first day, and increased gradually and slowly in the subsequent 27 days. In the scaffolds with a low concentration ZOL, more osteoclasts adhered and proliferated; in the 50 μmol/L scaffolds, spheroid cells appeared; the spheroid cells increased and even apoptosis occurred with an increase in the ZOL concentration. RT-PCR showed that the expression of Ctsk gene and TRAP gene increased with the increased ZOL concentration, peaked in the 50 μmol/L scaffolds, and then decreased with the increased concentration, showing statistically significant differences ( P < 0.05). Western-blot showed that the expression pattern of Ctsk and TRAP was similar to that of their related genes. Conclusions:The novel PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs demonstrate good mechanical properties and an anti-osteoporosis effect via their topical sustained drug release. The scaffolds with a ZOL concentration of 50 μmol/L may exert the best effect on inhibition of osteoclasts.

Knockdown the expression of ku70 and lig4 in HEK293T cells by CRISPR/Cas13 system / 生物工程学报

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated proteins (Cas) system is a hotspot of gene editing and gene expression research, in which CRISPR/Cas13 system provides a new direction for RNA interference and editing. In this study, we designed and synthesized the corresponding gRNAs of CRISPR/Cas13a and CRISPR/Cas13b systems in non-homologous end joining (NHEJ) pathway, such as Ku70 and Lig4, and then detected the expression of ku70 and lig4 in HEK293T cells. The CRISPR/Cas13a system could efficiently knockdown the mRNA expression of ku70 and lig4 more than 50%, and CRISPR/Cas13b system also suppressed ku70 and lig4 about 92% and 76%, respectively. Also, CRISPR/Cas13a, b systems could down-regulate Ku70 and Lig4 proteins level to 68% and 53%, respectively. The study demonstrates that the CRISPR/Cas13 system could effectively knockdown the expression of RNA and protein in HEK293T cells, providing a new strategy for gene function and regulation research.

Progress in epidural labor analgesia-related intrapartum fever / 中华围产医学杂志

Gravidas receiving epidural labor analgesia are at an increased risk for intrapartum fever due to unknown mechanism, which may be related to thermoregulation, non-infectious inflammatory, continued use of local anesthetic agents and trauma from epidural catheter insertion. Epidural labor analgesia-related intrapartum fever is associated with excessive obstetric interventions, higher rates of cesarean and assisted vaginal deliveries, unnecessary maternal and neonatal exposure to antibiotics, and adverse neonatal outcomes. Hence it is imperative to explore its etiology and shorten the labor with a safe and effective measure to reduce the occurrence of intrapartum fever.

Effects of gender and age on protein secretion in saliva of transgenic mice expressing human nerve growth factor / 生物工程学报

Nerve growth factor (NGF) can promote the development, differentiation and regeneration of neurons. Recently, in order to efficiently produce human NGF (hNGF) drugs with better efficacy, we created transgenic mice expressing hNGF specifically in their salivary glands, and purified highly active hNGF protein from their saliva. Some studies reported that the NGF secretion in mouse saliva is affected by gender and age. Here, in order to select hNGF transgenic mice with high NGF secretion for saliva collection and hNGF purification, we divided transgenic mice into 4 groups, including 28-day-old young males and females, 63-day-old adult males and females. We compared their saliva volume, total salivary protein amount, salivary mNGF protein amount and salivary hNGF protein amount. The results showed that the saliva volume as well as amounts of total salivary protein, salivary mNGF protein and salivary hNGF protein secreted by 63-day-old transgenic mice were significantly higher than those secreted by sex-match 28-day-old transgenic mice, and the salivary hNGF protein amount secreted by male transgenic mice at the age of 63 days was significantly higher than that of female transgenic mice at the same age; Among 4 groups of mice, 63-day-old male transgenic mice secreted the highest salivary hNGF content, which was about 46 times higher than that secreted by the 28-day-old female transgenic mice. Therefore, 63-day-old male transgenic mice should be selected for saliva collection and hNGF purification.

Tail-suspended model simulating mouse oocytes maturation inhibited with microgravity / 生物医学工程学杂志

We studied the effects of simulated microgravity on mouse oocytes maturation, and analyzed whether the tail-suspended model can be applied to investigate simulated microgravity effects on reproductive processes in female mice. Mouse oocytes were cultured in vitro with microgravity simulated by a rotating wall vessel bioreactor and by tail-suspended model, and the maturation rate of the mouse oocytes in the two models were examined in vivo. The maturation rate of mouse oocytes cultured in simulated microgravity was 8.93%, and that was 72.33% in 1g gravity. In ratio, oocyte maturation rate had no significant difference between the rotational group and control group. Microgravity simulated by the tail-suspended model inhibited mouse oocytes maturation and increased the rate of oocytes abnormity. The maturation rate of tail-suspended mouse oocytes was 14.54%, which was significantly lower than that of control group. Tail-suspended model should be an ideal model to investigate simulated microgravity effects on reproductive processes of female mice.

Construction of a Pichia pastoris recombinant strain capable of over-expressing phytase and endoglucanase / 生物工程学报

Both phytase and endoglucanase are additives in feed for mono-gastric animal known for their effects. Recombinant vector pPICZalpha-EG was constructed and transformed to GS115-phyA, a Pichia pastoris strain that had integrated with phytase gene, generating GS115-phyA-EG. Both phytase and endoglucanase activities in the supernatant were determined after methanol induction of GS115-phyA-EG. Phytase and endoglucanase activity reached 39.4% and 56.2% activity compared to GS115-phyA and GS115-EG, respectively. Properties of the mixed enzyme suggest that the optimal temperature and pH value be 55 degrees C and 5.5 respectively. Both phytase and endoglucanase showed greater than 80% activity across temperature ranges 45 degrees C to 55 degrees C and pH ranges 4.5 to 5.5. Expressing more than one enzyme in one system could save time and money during induced expression, and the mixed enzyme might apply for treating forge before feeding with poultry.