Effects of RGD peptides-grafted porous tantalum on morphological change of MG63 osteoblasts-tantalum conjunctive interface and expression of osteogenesis factors / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effects of the Arg-Gly-Asp polypeptedes (RGD) peptides-modified porous tantalum surface on osteoblasts morphology and expressions of osteogenesis factors, and to evaluate RGD peptides promotes junctura ossium of tantalum-bone interface in vivo.@*METHODS@#RGD peptides of different concentrations (1 g/L, 5 g/L, and 10 g/L) were loaded to porous tantalum slices with a diameter of 10 mm and a thickness of 3 mm by physical absorption. The 3rd generation of MG63 cells were co-cultured with tantalum and divided into 4 groups: Ta-cells (control) group, 1 g/L cells/Ta/RGD group, 5 g/L cells/Ta/RGD group, and 10 g/L cells/Ta/RGD group. Porous tantalum compo-sites and osteoblasts-tantalum interface were observed by scanning electron microscopy. The adhesion rate of osteoblasts was detected and immunocytochemistry was used to detect the expressions of filamentous actin (F-actin), osteocalcin (OC) and fibronectin (FN).@*RESULTS@#The scanning electron microscope (SEM) revealed that osteoblasts distributed on the surface of porous tantalum and secreted extracellular matrix on outside and inner of micro-pores. The osteoblasts adhesion rate on porous tantalum modified with RGD was higher than that in the unmodified porous tantalum at the end of 24, 48, and 72 hours. The best adhesion effect was got in 5 g/L cells/Ta/RGD group at hour 48 [(68.07±3.80) vs. (23.40±4.39), P<0.05]. The results of immunocytochemistry showed that the expressions intensity of F-actin, OC and FN in osteoblasts on porous tantalum modified groups with RGD were stronger than that in the unmodified groups, and the expressions of 5 g/L cells/Ta/RGD group were significantly higher than those in the 10 g/L group and 1 g/L group [OC: (18.08±0.08) vs. (15.14±0.19), P<0.05; (18.08±0.08) vs. (14.04±0.61), P<0.05. FN: (24.60±0.98) vs. (15.90±0.53), P<0.05; (24.60±0.98) vs. (15.30±0.42), P<0.05. F-actin: (29.20±1.31) vs. (24.50±1.51), P<0.05; (29.20±1.31) vs. (16.92±0.40), P<0.05]. Correspondingly F-actin in osteoblasts was showed in longitudinal arrangement, and the expressions intensity was stronger than those OC and FN.@*CONCLUSION@#The RGD peptides is beneficial to enhance adhesion of osteoblast, spreading and reorganization of cytoskeleton on porous tantalum surface and improve the interface morphology, further promoting osteoblasts-tantalum conjunctive interface osseointegration.

Application of allogeneic bone in surgical treatment of benign bone neoplasm / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the clinical outcomes of allogeneic bone grafting for bone defect resulting from benign neoplasm resection and discuss the clinical application and bone defect repair mechanisms of allogeneic bone.</p><p><b>METHODS</b>A retrospective review was conducted of 135 patients with benign neoplasm resection who received bone defect filling with the allogeneic bone graft.</p><p><b>RESULTS</b>In the 104 patients with complete clinical follow-up data, 96 achieved bone union, 7 experienced relapses to require surgical intervention and 1 had severe infection to lead to failure of the operation. The mean time for bone union was 9.7 months, and during the follow-up, no viral disease in relation to the graft was found after surgery.</p><p><b>CONCLUSION</b>Bone defect filling with allogeneic bone graft can be simple and safe in comparison with that with autograft or other biomaterials, and the bone healing time, infection rate and local tumor recurrence can be comparable with the autograft.</p>

Effect of variation in 5'-regulatory region of insulin receptor substrate-1 gene on gene expression / 中南大学学报(医学版)

UNLABELLED@#OBJECTIVE; To determine the effect of a variation of CAG-rich region, which was found in the 5'-regulatory sequence of insulin receptor substrate-1(IRS-1) gene in Type 2 diabetes mellitus(T2DM) patients, on gene expression and its mechanism.@*METHODS@#The recombinants, pGL2.P-T3 and pGL2.P-T5, were constructed with luciferase reporter vector, pGL2 promoter. T3 and T5 were wild-type and variant alleles, respectively. The recombinants were cotransfected with pSV-beta-galactosidase control vector to Hela cells. Luciferase assay was performed to assess transcriptional activity. The electrophoresis mobility shift assay(EMSA) and DNA footprint assay were applied to determine the interaction between the DNA regulatory sequences and nuclear proteins of Hela cells.@*RESULTS@#The relative transcription activity of T5 was lower than that of T3 [(7.76+/-1.05)% vs (9.98+/-1.40)%, P<0.05]; EMSA showed both T3 and T5 formed a single retarded band in gel with the same mobility with nuclear proteins; T5 had 2 binding sites for transacting factors, CGCGCCCGCGGGCGGCGGC and GGGCGGCTGGTGGCGGCTG, which was the same as T3.@*CONCLUSION@#Although the variation in T5 do not alter the DNA-binding sites for Hela cell nuclear extracts, the notable decrease in gene transcription activity induced by it may be an important factor to the development T2DM in the carrier.

Effects of long-term estrogen replacement treatment on the blood pressure and expression of IR and IRS-1 in myocardium / 中南大学学报(医学版)

OBJECTIVE@#To determine the effects of long-term estrogen replacement treatment on blood pressure and expressions of insulin receptor (IR) and insulin receptor substrate-1 ( IRS-1) in myocardium.@*METHODS@#Fifty female SD rats were randomly divided into 3 groups. And then sham ( n = 16), ovariectomy (OVX, n = 17), and estrogen replacement treatment group (OVX + E2, n = 17) were established. Systolic blood pressure of tail artery was determined by tail-cuff technique before the operation and on week 12 after the operation. The expressions of IR and IRS-1 were measured by RT-PCR in myocardium of SD rats.@*RESULTS@#Blood pressure [ (118.75+/-2.77) mmHg] in OVX was significantly higher than that in the sham [ ( 103.86+/-1.84) mmHg, P 0.05 ). The difference of IR expression has no statistical significance among the 3 groups.@*CONCLUSION@#Long-term estrogen replacement treatment might protect cardiovascular system through decreasing the blood pressure and inducing the expression of IRS-1 in myocardium. However, plasma estrogen level doesn't significantly influence the IR expression.

Effects of long-term estrogen replacement treatment on the expression of bcl-2 and H-ras in rat endometrium / 中南大学学报(医学版)

OBJECTIVE@#To investigate the effects of long-term estrogen replacement treatment (ERT) on the expression of bcl-2 and H-ras in rat endometrium.@*METHODS@#Thirty 5-month-old SD female rats were randomly divided into 3 groups: Control group ( sham operated and vehicle injected, n 10) , OVX group (OVX operated and vehicle injected, n = 10) , and ERT group (OVX operated and 17 beta-estradiol injected, n = 10). The rats were killed in the 13th week and the uteri were isolated and weighed, pathologically analyzed, and we measured the thickness of the endometrium. Immunochemistry and in situ hybridization analysis were used to examine the changes of bcl-2 and H-ras mRNA and Bcl and H-ras protein expression in the endometrium of the rats.@*RESULTS@#Uterine weight and endometrial thickness of OVX decreased much more than those of the control (P <0.01 ) and ERT rats (P < 0.01). One simple hyperplasia and one squamous metaplasia of endometrium were found in ERT rats. Quantitatively, bcl-2 and H-ras mRNA and Bcl and H-ras protein level of ERT were higher than those of OVX rats (P < 0.01 ), and there were no statistical significances between the ERT group and the control rats.@*CONCLUSION@#Long-term estrogen replacement can keep the endometrium from atrophy, and lead to the genesis of simple hyperplasia and squamous metaplasia of the endometriun, which can increase the risk of endometrial carcinomas. Estrogen may inhibit apoptosis and promote the proliferation of endometrial cells through increasing the expression of bcl-2 and H-ras mRNA and Bcl-H-ras proteins.