ABSTRACT
Objective To construct a two-dimensional (2D) composite membrane and a three-dimensional (3D) biomimetic scaffold by silk fibroin (SF), type I collagen (Col-I) and hydroxyapatite (HA) blends in vitro, so as to study its physicochemical properties, as well as biocompatibility and explore the feasibility of its application in tissue engineering scaffold materials. Methods 2D composite membranes and 3D scaffolds were prepared by blending SF/Col-I/HA at the bottom of cell culture chamber and low temperature 3D printing combined with vacuum freeze drying. The biocompatibility was evaluated by mechanical property testing, scanning electron microscope and Micro-CT to examine the physicochemical properties of the material, and cell proliferation was detected to evaluate its biocompatibility. Results Stable 2D composite membrane and 3D porous structural scaffolds were obtained by blending and low temperature 3D printing. The mechanical properties were consistent. The pore size, water absorption, porosity and elastic modulus were all in accordance with the requirements of constructing tissue engineering bone. The scaffold was a grid-like white cube with good internal pore connectivity; HA was evenly distributed in the composite membrane, and the cells were attached to the composite membrane in a flat shape; the cells were distributed around pore walls of the scaffold. The shape of the shuttle was fusiform, and the growth and proliferation were good. Conclusions The composite membrane and 3D scaffold prepared by SF/Col-I/HA blending system had better pore connectivity and pore structure, which was beneficial to cell and tissue growth and nutrient transport. Its physicochemical properties and biocompatibility could meet the requirements of bone tissue engineering biomaterials.
ABSTRACT
Objective To investigate the role and mechanism of nico-tinamide adenine dinucleotide phosphate oxidase 4 (NAPHD oxidase 4,Nox4)-mediated reactive oxygen species (ROS) generation on high-dose dexamethasone (DEX) induced apoptosis in osteoblasts.Methods According to culture conditions,3rd passage of murine osteoblastic MC3T3-E 1 cells were divided into control group,Dexamethasone group,Dexamethasone+NAC (N-acetyl-L-cysteine) group,NAC group,Dexamethasone+DPI (Diphenyleneiodonium) group and DPI group.24 hours after culture,the morphology of osteoblasts was observed by inverted phase contrast microscope.Cell viability was determined by MTT assay.The generation of ROS in osteoblasts was measured using a fluorescent probe DCFH-DA.The apoptosis of each group was observed through Hoechst staining.The mRNA level and protein expression of Nox4 were detected by real-time quantitative PCR and Western Blot.In addition,after silence of Nox4 with small interfering RNA (siRNA),the ROS generation was further detected by a fluorescent probe DCFH-DA.Results After treatment with 1000 nmol DEX for 24 hours,compared to control group,the results of inverted phase contrast microscope and MTT showed that osteoblasts in DEX group exhibited more obvious signs of shrinkage and deformation with decreased cell viability.After intervene with NAC and DPI,morphology of osteoblasts was good with increased viability of osteoblasts.Compared to control group (5.86％± 0.28％),the production of ROS in DEX group (45.14％±1.49％) was significantly increased (P=0.000).The apoptotic rates in DEX group (29.60％± 1.52％) was significantly increased compared with control group (4.12％±0.67％) (P=0.000).Compared to DEX group,the production of ROS generation in DEX+NAC group (28.06％±1.61％) and DEX+DPI group (23.70％±1.28％) was significantly decreased (P=0.000).It presented that NAC or DPI significantly decreased the formation of ROS.Compared to DEX group,the apoptotic rate in DEX+NAC group (8.94％± 1.47％) and DEX+DPI group (12.96％±2.03％) was significantly decreased (P=0.000).It presented that NAC or DPI significantly decreased osteoblast apoptosis.In addition,the Nox4 mRNA level in DEX group was 2.67-fold compared with control group (t=-10.301,P=0.009).The difference had statistically significance.The protein expression of Nox4 in DEX group was 2.37-fold compared with control group (t=-15.542,P=0.004).The difference has statistically significance.After silence of Nox4 by siRNA,the generation of ROS in DEX+Nox4 siRNA group (14.53％± 1.00％) was decreased by 16.92％ compared with DEX group 31.45％±0.72％ (P=0.000).The difference had statistically significance.Conclusion Nox4-mediated ROS generation plays an important role in osteoblasts apoptosis induced by high-dose dexamethasone.It provided us the new target in the management of Nox4 to provide possible therapy for steroid-induced avascular necrosis of the femoral head (SANFH).
ABSTRACT
Objective To investigate the incidence and related risk factors of delirium in elderly patients with hip frac-ture. Methods From October 2014 to February 2017, 306 patients with femoral neck fracture or intertrochanteric fracture more than 65 years old underwent elective hip arthroplasty (hip arthroplasty, proximal femoral nail fixation) were retrospective-ly analyzed. Patients' general information was recorded: age, sex, body mass index (BMI), history of diabetes mellitus, history of coronary heart disease, cerebral infarction, preoperative biochemical tests, left ventricular ejection fraction, thrombosis of both lower extremities, intraoperative status (ASA score, NYHA heart function score, anesthesia, anesthesia time, etc.), periop-erative blood transfusion, biochemical examination on the first day after surgery, perioperative albumin consumption, etc.; ac-cording to whether delirium happened after surgery, those patients were divided into delirium group and non-delirium Group and analyzed the incidence of postoperative delirium. Using univariate logistic regression analysis screened factors associated with postoperative delirium. The results were entered into the multivariate logistic regression analysis, screening the high risk factors for postoperative delirium.Results The incidence of delirium was 59(19.29%) after perioperative hip fracture, includ-ing 23 males and 36 females, ranging in age from 70 to 93 years with an average of (81.9±5.4) years. 247 cases had no deliri-um,including 81 males and 166 females,aged 65-96 years,with an average(76.4±8.1)years.The factors of age,length of hos-pital stay, days before surgery, preoperative hematocrit, perioperative albumin consumption, perioperative blood transfusion, preoperative leukocyte levels, preoperative albumin levels, preoperative creatinine, urea level, Mallampati classification (Mar-kov grade), cardiac function score (NYHA score), ASA score, intraoperative blood loss, postoperative leukocyte level, left ven-tricular ejection fraction, previous cerebral infarction, history of coronary heart disease, and diabetes were statistically signifi-cant different; univariate logistic regression analysis showed that the factors of age, ASA score, history of diabetes mellitus, length of hospitalization, and perioperative albumin consumption were demonstrated to have relationship with the occurrence of postoperative delirium. Multivariate regression analysis showed that age, history of diabetes and ASA score are the high risk factors of postoperative delirium.Conclusion Age,history of diabetes mellitus and ASA score are risk factors of delirium in el-derly patients with hip fracture.Those patients older than 75 years,with the history of diabetes mellitus or ASA score> 2 points were at higher risk of postoperative delirium,which prolongs hospitalization and increases protein consumption.