Three-Dimensional Finite Element Analysis on Invisible Dental Appliance under Different Moving Modes / 医用生物力学

Objective To analyze effects of different elastic modulus, thickness and tooth movement on deformation of the invisible dental appliance by finite element method, so as to provide theoretical references for orthodontic doctor to formulate the orthodontic treatment scheme. Methods A total of 12 finite element models of invisible appliances were established with 4 kinds of thickness and 3 kinds of elastic modulus. The displacement load of the tilting movement was applied to the 12 models, and the maximum Von Mises stress and deformation of the appliance were analyzed; the deformation of the appliance was analyzed by applying the displacement load of inclined, parallel and intrusion to the optimal model. Results The maximum Von Mises stress increased with the elastic modulus and thickness of the invisible appliance increasing. The deformation decreased with the appliance thickness increasing. When the tooth was under inclined and parallel movement, the maximum deformation was found in the corresponding part of the tooth. Some of the corresponding parts of the immovable teeth were deformed to the lip convex side and some to the tongue side with internal concave deformation, and the appliance deviated seriously to top of the crown when the tooth was under intrusion movement. Conclusions The optimum thickness of invisible dental appliance was 0.75 mm, and the elastic modulus 816.31 MPa that currently used in clinic was suitable. In the digital model, the tongue side of the teeth corresponding to the labial protruding part and the lip side of the tooth corresponding to the concave side of the tongue side can be thickened, and the invisible appliance can be optimized by using the thickened digital model.

Effects of pirfenidone on renal fibrosis in mice with diabetic nephropathy and its mechanisms / 中华肾脏病杂志

Objective To investigate effects of pirfenidone (PFD) on diabetic nephropathy model in db/db mice and to explore its possible mechanisms.Methods (1) Wild-type mice were as the normal control group,and db/db mice were divided into model group and PFD group,with 6 mice in each group.In the PFD group mice were administered continuously by 250 mg· kg-1· d-1 PFD for 18 weeks,and mice in the other two groups were administered by 0.5％ sodium carboxymethyl cellulose.Blood glucose and 24 h urinary albumin were measured.The pathological changes of renal tissue were evaluated by PAS staining,PASM staining,Masson staining and Sirius red staining.The expression of collagen type Ⅳ in kidney tissues was detected by immunohistochemistry.(2) Mouse mesangial cells (SV40 MES-13 cells) were cultured as research objects.They were divided into control group,hyperosmolar group,high glucose (HG) group,and 50,100,200,400,800,1600 mg/L PFD+HG group.BrdU cell proliferation test was used to evaluate cell proliferation rate.Cells were divided into control group,hyperosmolar group,HG group and PFD+HG group.The mRNA expressions of α-smooth muscle actin (α-SMA),collagen type Ⅰ,collagen type Ⅳ,transforming growth factor-β1 (TGF-β1),interleukin (IL)-1β,IL-6 and monocyte chemotactic protein-1 (MCP-1) were detected by real-time PCR.Results (1) Compared with normal control group,the model mice had higher weight,blood glucose and 24 h urinary albumin,accompanied with glomerular hypertrophy,mesangial area expansion,tubulointerstitial fibrosis and deposition of collagen type Ⅳ (all P ＜ 0.05).Compared with those in model group,in PFD group 24 h urinary albumin decreased,glomerular hypertrophy,mesangial area expansion and tubulointerstitial fibrosis alleviated,and the protein expression of collagen type Ⅳ inhibited (all P＜0.05).(2) Compared with those in HG group,MES-13 cell proliferation rates of 100,200,400,800,1600 mg/L PFD+HG groups decreased (all P ＜ 0.05),and the mRNA expressions of α-SMA,collagen type Ⅰ,collagen type Ⅳ,TGF-β1,IL-1β,IL-6 and MCP-1 reduced in 400 mg/L PFD+HG group (all P ＜ 0.05).Conclusions PFD can inhibit high glucose-induced proliferation and activation of glomerular mesangial cells,decrease the expression of TGF-β1 and proinflammatory factors,as well as reduce the synthesis of collagen,which improve renal fibrosis of db/db mice.

Fluorofenidone reduces renal fibrosis in diabetic kidney disease mice / 中华肾脏病杂志

Objective To investigate the effects of fluorofenidone(AKF-PD)on diabetic kidney disease in db/db mice and its possible mechanisms.Methods(1)Fifty-six mice aged 8 weeks(half male and half female),including 42 db/db mice and 14 wild-type mice were studied.Fortytwo db/db mice randomly were divided into model group(mock-treated diabetic db/db mice),AKF-PD(250 mg· kg-1· d-1)treatment group and losartan(20 mg· kg-1· d-1)treatment group.Wild-type mice and model mice were treated with vehicle(0.5％sodium carboxymethylcellulose),while the treatment groups received either AKF-PD or losartan.After 18 weeks,the blood glucose and urinary albumin were measured,the pathological changes of kidney were observed by PAS staining.The protein expressions of type Ⅳ collagen and fibronectin(FN)in kidney tissue were detected by immunohistochemistry.(2)Mouse glomerular mesangial cells(MES-13 cells)were divided into six groups:normal glucose group(5.5 mmol/L glucose),hypertonic group(5.5 mmol/L glucose+19.5 mmol/L mannitol),high glucose group(25.0 mmol/L glucose),AKF-PD group(25.0 mmol/L glucose+400 mg/L AKF-PD)and losartan group(25.0 mmol/L glucose+2 μmol/L losartan).After 72 h treatment,the expressions of type Ⅰ collagen,type Ⅳ collagen and transforming growth factor-β1(TGF-β1)mRNA were detected by realtime PCR,and the content of TGF-β1 protein in the culture supernatant was detected by ELISA.Results(1)Compared with the wild type mice,model mice had increased weight,blood glucose and glomerulosclerosis index(all P ＜ 0.01),accompanied with heavy albuminuria,glomerular hypertrophy,mesangial area expansion and deposition of collagen type Ⅳ and FN(all P ＜ 0.01).Compared with model mice,in AKF-PD and losartan groups 24 h urinary albumin and glomerulosclerosis index decreased(all P ＜ 0.01),glomerular hypertrophy and mesangial area expansion alleviated,and the protein expressions of collagen type Ⅳ and FN were inhibited(all P ＜ 0.01).(2)Compared with the normal glucose group,the mRNA expressions of type Ⅰ collagen and type Ⅳ collagen increased in high glucose group,meanwhile the mRNA and protein expressions of TGF-β1 increased(all P ＜ 0.01).In AKF-PD and losartan groups the expressions of type Ⅰ collagen,type Ⅳ collagen and TGF-β1 were inhibited as compared with high glucose group(all P ＜ 0.05).Conclusion Fluorofenidone may play an anti-fibrotic effect in db/db mice by reducing the expression of TGF-β1 and inhibiting collagen synthesis in glomerular mesangial cells.

Effect of curcumin on the expression of p-STAT3 and IκB in db/db mice / 中南大学学报(医学版)

OBJECTIVE@#To determine the effect of curcumin on diabetic nephropathy in db/db mice and its possible mechanism.@*METHODS@#Ten female db/db mice were randomly divided into 2 groups: one was treated with curcumin at 200 mg/(kg.d) and the other was a placebo group. Five age-matched db/m mice were grouped as the controls. In the curcumin group, curcumin was administered to db/db mice for 18 weeks. At the end of the experiment, the blood glucose and albumin were measured, and the kidney tissue sections were stained with PAS to observe the pathological changes. The expression of collagen IV and FN in the kidney was detected by immunohitochemistry staining. Western blot was used to detect the phosphorylation of signal transducer and activator of transcription 3 (STAT3) and IκB in the kidney.@*RESULTS@#Compared with db/m mice, the weight and blood glucose of db/db mice were markedly increased, accompanied with heavy proteinuria, glomerulus hypertrophy, mesangial area expansion, thickening of basement membrane and ECM deposition. The phosphorylation of STAT3 was upregulated and the degradation of IκB was increased. Compared with the db/db mice, curcumin significantly decreased the urinary albumin, inhibited the phosphorylation of STAT3 and the degradation of IκB, and reduced the expression of collagen IV and FN in the kidney.@*CONCLUSION@#Curcumin can obviously decrease albuminuria and attenuate glomerular sclerosis in diabetic db/db mice by inhibiting phosphorylation of STAT3 and degradation of IκB.

Biological characteristics of rat bone marrow mesenchymal stem cells transfected with hypoxta-inducible factor-1α gene / 中华麻醉学杂志

ObjectiveTo evaluate the biological characteristics of rat bone marrow mesenchymal stem cells (BMSCs) transfected with hypoxia-inducible factor-1α(HIF-1 α) gene.MethodsThe rat BMSCs of 3rd generation and the vector expressing HIF-1α gene (pcDNA3.1-HIF-1α) were provided by department of anesthesia,Tangdu Hospital,the 4th Military Medical University.BMSCs expressing HIF-1α gene (BMSCs-HIF-1α cells) were constructed by transfection of vector pcDNA3.1-HIF-1α into BMSCs by means of electroporation.Successful transfection of HIF-1α gene was confirmed by immuno-cytochemistry.Simple BMSCs and BMSCs-pcDNA3.1 cells were used as control cells.After being cultured in hypoxic condition HIF-1α expression was detected by Western blot analysis.Flow cytometry was used to determine the proportion of cells in G1,G2 and S phase and detect apoptosis.The proliferation index (PI) was calculated.The cell growth curve was described by MTT assay and the number of the 3 types of cells was recorded.ResultsA large number of deep blue granules were observed in the nuclei of BMSCs-HIF-1α cells using immuno-cytochemistry but no such granule was found in the two types of control cells.HIF-1α expression was significantly up-regulated and apoptosis rate (the number of apoptotic cella/the total number of cells examined) decreased in BMSC-HIF-1α cells compared with the control cells.The proportion of cells in S and G2 phase was significantly higher and the proportion of cells in G1 phase was significantly lower and PI higher in BMSCs-HIF-1α cells than in the control cells.The number of BMSCs-HIF-lα cells was significantly higher than the number of the two types of control cells at day 3-8 of culture.There was no significant difference in the above variables between BMSCs and BMSCs-pcDNA3.1 cells.ConclusionBMSCs-HIF-1α is successfully constructed by transfection of vector pcDNA3.1-HIF-1α gene into BMSCs by means of electroporation.