Characterization of PEG-SH modified GNPs/miR-29 nanoparticles and cytocompatibility / 中华骨科杂志

Objective:To prepare PEG-SH modified GNPs/miR-29 nanoparticles and to investigate the proliferation and differentiation of neural stem cells induced by PEG-SH modified GNPs/miR-29 nanoparticles.Methods:PEG-SH modified GNPs/miR-29 nanoparticles were developed by oxidation-reduction method and were tested for UV absorption spectrum, particle size distribution and zeta potential of nanoparticles. A total of 15 adult male Sprague Dawley (SD) rats were used to establish spinal cord injury model by modified Allen method. The artificial miR-29 and PEG-SH modified GNPs/miR-29 nanoparticles were implanted into the injury site of spinal cord respectively. The stability of miR-29 expression was analyzed by gel electrophoresis. The neural stem cells were isolated and cultured from 10 SPF grade neonatal rats. It was identified by Nestin, GFAP and NSE antibodies. The activity and proliferation of neural stem cells in synthetic miR-29, PEG-SH GNPs and PEG-SH GNPs/miR-29 nanoparticles group was detected by CCK-8 assay. Neural stem cells were cultured with synthetic miR-29, PEG-SH GNPs and PEG-SH GNPs/miR-29 nanoparticles for 1 week. The density, length and number of neuritis were investigated.Results:The solution of PEG-SH modified GNPs showed a brownish red appearance. The spheres were in uniform distribution under transmission electron microscope. The results of UV absorption spectrum showed a single peak wave. The peak value of UV absorption was near 523 nm. The zeta potential increased gradually with the increased content of PEG-SH. The peak value of zeta potential was 22.5±5.2 mV. With the increase of content of PEG, the particle size of PEG-SH modified GNPs rapidly reached peak value at the early stage and then decreased rapidly to a relatively stable level. The synthetic miR-29 and PEG-SH modified GNPs/miR-29 nanoparticles were implanted into the injury site of spinal cord. At 0-6 h, clear band was observed in the synthetic miR-29 group. However, the band was disappeared rapidly at 12-24 h. In PEG-SH GNPs/miR-29 group, clear band were always observed. The OD values of miR-29 group were 0.34±0.17, 0.78±0.31, 1.28±0.68, 1.64±0.38 at 1, 3, 5 and 7 d after inoculation respectively. There was no significant difference in OD values compared with DMEM group. There was no significant difference in OD values among GNPs, PEG-SH GNPs, PEG-SH GNPs/miR-29 and DMEM group. The density (56.38±3.65 μm 2), length (78.25±3.72 μm) and the number [(356±34.52) /1,000×high power field] of neurites in PEG-SH GNPs/miR-29 group were higher than those in miR-29 group, PEG-SH modified GNPs group and saline group. However, there was no significant difference in the density, length and number of neurite between PEG-SH GNPs/miR-29 and serum group. Conclusion:PEG-SH modified GNPs/miR-29 nanoparticless have good biological properties. It can induce the proliferation and differentiation of neural stem cells with protective effects on miR-29.

Protective effect of LR-90 on articular cartilage in rabbit model of osteoarthritis / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the protective effect of LR-90 on articular cartilage in rabbit model of osteoarthritis.</p><p><b>METHODS</b>The cultured rabbits chondrocytes were assigned to be treated with IL-1β (10ng/ml) or IL-1β (10ng/ml)+LR-90 (50 mg/L). The mRNA expression of MMP-13, ADAMTS-5, aggrecan and collagen II in chondrocytes were assessed by real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). Twenty male New Zealand white rabbits underwent bilateral anterior cruciate ligament transection (ACLT) to establish a animal model of osteoarthritis. Four weeks after model established, on the basis of randomization one knee of each rabbit was treated with 50 mg/L LR-90 in normal saline (NS) (experimental group) and the other knee was treated with same volume of NS (control group), 1/week × 5. Nine weeks after ACLT all rabbits were sacrificed and the knee joints were evaluated by gross morphology and histology. The mRNA expression of IL-1β, MMP-13, ADAMTS-5, aggrecan and collagen Ⅱ in articular cartilage was analyzed by RT-PCR.</p><p><b>RESULTS</b>Gross morphology and Mankin histological evaluation showed that the extent and grade of cartilage damage in the experimental group were less severe than those in the control group.Compared to IL-1β group, LR-90 treatment suppressed the mRNA expression of MMP-13 and ADAMTS-5, and enhanced aggrecan and collagen Ⅱ mRNA expression. Consistent with the in vitro results, the intraarticular LR-90 administration suppressed the mRNA expression of IL-1β,MMP-13 and ADAMTS-5 (all P<0.01), while enhanced mRNA expression of aggrecan and collagen Ⅱ in cartilage (all P<0.01).</p><p><b>CONCLUSION</b>LR-90 protects against cartilage degradation and inhibits the progression of osteoarthritis in rabbit mode1 of osteoarthritis, which is associated with the suppressing IL-1β, MMP-13, ADAMTS-5 and promoting aggrecan and collagen Ⅱ mRNA expression in cartilage.</p>

Research of bio-ceramic coatings on Ti-based implants in biomedical application / 国际生物医学工程杂志

Titanium alloy has been used widely in fields of hard tissue replacement and repair,despite its characteristics of bio-inert material.Bio-ceramic coating deposited on Ti-based implants surface using surface modification technique can improve the bioactivity and biocompatibility of Ti-alloy material.The hydroxyapatite coating has been applied in clinic treatment,but this type of coating is still plagued with low crystallinity and poor bonding strength.In order to obtain an implant with excellent integrated properties,some novel bio-ceramic coating materials have been prepared.These materials having excellent bioactivity and biocompatibility and can directly bond with the Ti-based implants and the bone tissue.This review will present research status of the application of bio-ceramic coating on titanium alloy surface in biomedical fields

Development of the studies on engineered neural stem cells / 国际生物医学工程杂志

Stem cell is one of the hot spot in the research area of biomedical engineering. Special attentions are drawn to the research and application of neural stem cells. Neural stem cells exist widely in central nervous system, which has the capacity of self-renewal and the potential to differentiate into other cells. The so-called engineered neural stem cell is constructed by using the technique of genetic engineering to make it be able to express various neural growth factors with high-performance and stability. The engineered neural stem cells have a great potential in the therapy of diseases of central nervous system, especially the spinal cord injury. This article reviews the research development of engineered neural stem cells, the problems confronted with it, and the trend for research in the future.