Preparation and evaluation of fish skin acellular dermal matrix for oral guided tissue regeneration / 中国组织工程研究

BACKGROUND: Current oral restoration membranes are expensive with a potential risk of zoonotic virus, so new membranes are in need. OBJECTIVE: To prepare fish skin acellular dermal matrix and evaluate its efficiency of decellularization, biomechanical properties and biocompatibility, in order to explore its feasibility as an oral restoration membrane. METHODS: The skin of Astroconger Myriaster was harvested to prepare acellular dermal matrix by decellularization via a combination of physical method and chemical and biological reagents. The micromorphology of the material was observed under scanning electron microscope. Tissue composition was analyzed by hematoxylin-eosin, Masson and PAS staining. The DNA content was detected using a kit. The biocompatibility was evaluated through cytotoxicity and animal skin stimulation tests. RESULTS AND CONCLUSION: The prepared acellular dermal matrix: (1) was white or light yellow, with strength and toughness; (2) exhibited a double-layered structure composed of a dense layer and a loose layer; (3) was mostly composed of collagen without PAS positive substance, showing good decellularization; (4) had a significantly lower DNA content than natural fish skin and commercial oral restoration membrane; and (5) possessed good biocompatibility, with very low cytotoxicity and no stimulation to the animal skin. Therefore, the prepared acellular dermal matrix of fish skin shows a potential in the preparation of oral guided tissue regeneration membrane.

Expression of Nucleotide-binding Oligomerization Domain Receptor Protein 3 in Patients with Alzheimer's Disease and Vascular Dementia and Related Factors / 中国康复理论与实践

@#Objective To explore the role of nucleotide-binding oligomerization domain receptor protein 3 (NLRP3) inflammasome in the pathogenesis of dementia. Methods 16 patients with with Alzheimer's disease (AD), 22 patients with vascular dementia (VD) and 20 healthy persons with similar age were detected the level of NLRP3 mRNA with RT-PCR in peripheral blood mononuclear cells January, 2014 to October, 2015. The serum level of interleukin (IL)-1βand IL-18 were detected with ELISA. The total number of white blood cells (WBC) and serum total calcium were collected. Single factor correlation analysis was performed between NLRP3mRNA and IL-1β, or IL-18, or WBC, or calcium concentration. Results The levels of NLRP3 mRNA ranged from high to low were as in AD group>VD group>the healthy group (q>11.48, P<0.05). The serum level of IL-1βwas higher in AD group than in the the healthy group (q=16.74, P<0.05), but not significantly different between VD group and the healthy group, nor between VD group and AD group (P<0.05). There was no signifi-cant difference about IL-18 among AD group, VD group and the healthy group (P<0.05). NLRP3 mRNA was positively correlated with the serum levels of IL-1β(r=0.64) and calcium (r=0.58) in AD group. There was no correlation between NLRP3 mRNA and IL-18 or WBC (P<0.05). Conclusion The expression of NLRP3 inflammasome may be related with the pathogenesis of AD, but little impact on the pathogene-sis of VD.

Calcium facilitates NLRP3 inflammasome-induced oxidative stress in SHSY5Y cells / 中华行为医学与脑科学杂志

Objective To study calcium chelator BAPTA-AM antagonize the cellular oxidative stress induced by hydrogen peroxide ( H2 O2 ) and to explore the effect of calcium ion on the cell degeneration mediated by NLRP3.Methods The SHSY5Y cell model of oxidative stress was made by hydrogen perox-ide,then the cell model was treated with calcium ion carrier A23187 or BAPTA-AM,a higher efficiency cal-cium chelating agent.The cells were divided into 4 groups:H2O2 treatment group,H2O2+A23187 group, H2 O2+A23187 +BAPTA-AM group and control group.NLRP3 protein was detected by Western blot,and Caspase-1 and IL-1βwere detected by ELISA.Results NLRP3 expression was significantly increased in cells treated by hydrogen peroxide(P<0.05) .The NLRP3 protein continued to increase, and the expression of Caspase-1((57.1±19.2)pmol/L) and IL-1β((484.2±49.5)pg/ml) protein was also increased signifi-cantly in cells treated by A23187,and the difference had statistically significant for caspase-1 or IL-1βin H2O2+A23187 group compared with those in control group(Caspase-1:(26.8±12.9)pmol/L,IL-1β:(326.9 ±52.1) pg/ml) (P<0.05, P<0.01) .NLRP3,Caspase-1 and IL-1βwere all significantly reduced after adding a high-er efficiency calcium chelating agent BAPTA-AM.Conclusion Calcium overload is likely to enhance the oxidative stress induced by hydrogen peroxide and engender neurodegeneration mediated by NLRP3 inflammasome.

Biomechanical characteristics of placement methods of the thoracic pedicle screw system / 中国组织工程研究

BACKGROUND:Studies have shown that placement, needling point, angle and length of pedicle screws for thoracic vertebral fractures have been unified. Many studies concerned axial pul-out force and biomechanical behavior of a single screw, but few reports addressed the biomechanical behavior after the replacement with three kinds of screw connecting to rods. OBJECTIVE:To further observe and compare biomechanical behavior after three kinds of thoracic screw placement connecting rod using biomechanical testing, to understand the strength of thoracic pedicle screw replacement connecting rods, and the effects of its puling out on the stress of the bone surrounding the placement site. METHODS:The fresh frozen specimens of thoracic vertebra were divided into three groups at random: the pedicle fixation group, the transverse process-vertebral body fixation group, and modified rib transverse process fixation group. Thoracic pedicle screw system was inserted by the standard placement method in each group. The experiment was measured on the mechanical equipment. During puling out, the strength that bone bore was described with dynamic curve, folowed by statistical analysis. The difference in the gripping force on the thoracic vertebra among three kinds of screw placement method was compared. RESULTS AND CONCLUSION: Among three kinds of screw placement methods and among three kinds of screw placement methods on the injured vertebral body, the gripping force was significantly bigger in the pedicle fixation group than in the transverse process-vertebral body fixation group and modified rib transverse process fixation group (P < 0.01). No significant difference in the gripping force was detected between the transverse process-vertebral body fixation group and modified rib transverse process fixation group. Results verified that the stability of loading ability was apparently better in the pedicle fixation group compared with the transverse process-vertebral body fixation group and modified rib transverse process fixation group.