ABSTRACT
BACKGROUND:Tantalum rod implant technology is a new method of early osteonecrosis treatment. Current research on stress distribution before and after tantalum rod implant in different sizes of femoral head necrosis area is few. OBJECTIVE:To analyze the stress distribution before and after tantalum rod implantation in different sizes of necrotic femoral head area using three-dimensional finite element method. METHODS:Three-dimensional finite element models of normal femoral head and necrotic femoral head of 15, 20 and 30 mm diameterwere constructed. Eight measuring points were chosen on two tiers of each necrotic model to detect the stress distribution and its alteration before and after tantalum rod implantation. RESULTS AND CONCLUSION:(1) Stress concentration werefound on every necrotic femoral head, most pronounced on the one with 30 mm lesion. (2) Tantalum implant appeared to reduce the stress concentration generaly. Comparison of the peak points of these models indicated most significant benefit in 15 mm lesion, next in 30 mm lesion, last in 20 mm lesion. (3) Results indicate that larger lesion entails more concentrated stress distribution and more likely to colapse. Tantalum rod implantation can delay the development of necrosis of the femoral head, andismost effective in smal lesion.
ABSTRACT
BACKGROUND:Transgenosis of basic fibroblast growth factor (bFGF) gene has been successfully performed into the muscle satellite cells of rat extraocular muscles in the previous study of the research group, proving that bFGF could express in the myoblasts of extraocular muscles, also promote cell proliferation and differentiation.OBJECTIVE: To further investigate the methods for regulating the expression of the bFGF in myoblasts following transfection. METHODS: Target gene bFGF was connected with inducing expression vector pcDNA4/T0/myc-His?A, followed by masculine clone sequencing identified by colony PCR and enzyme digestion, EcoR I and Hind III restriction enzyme digestion, as well as Xho I single enzyme verification. C2C12 myoblasts antibiotics sensitivity was screened and finally defined. By use of lipofection transfection technology, cell lines where C2C12 stably expressed pcDNA6/TR were estabolishd and then identified by Western blot. The pcDNA4/TO/myc-His?A-bFGF was transfected into pcDNA6/TR- C2C12 cells. The bFGF expression and secretion in C2C12 cells following tetracycline-induced pcDNA4/TO/myc-His?A-bFGF transfection were determined by immunofluorescence and Western blot, the controls were established.RESULTS AND CONCLUSION: ① The conjunction between the bFGF and inducing expression vector pcDNA4/TO/myc-His?A was proved successfully by sequencing comparison, double digestion and single digestion. ②The minimal lethal concentration of blasticidin to C2C12 cells was 10 mg/L, while that of zeocin was 750 mg/L. ③ The pcDNA6/TR-C2C12 cell lines were established correctly. ④ The myoblasts treated by tetracycline and transfected with pcDNA4/TO/myc-His?A-bFGF were positive for gene expression, those untreated exhibited a negativity; bFGF protein could be produced in myoblasts treated by tetracycline and transfected with pcDNA4/TO/myc-His?A-bFGF, the production reached a peak at 24 hours, while those untreated can not produce bFGF protein. Results suggest that the bFGF expression in the myoblasts can be controlled by tetracycline inhibition and regulatory systems.
ABSTRACT
BACKGROUND: Experiments have demonstrated that exogenous basic fibroblast growth factor (bFGF) promotes the growth and survival of skeletal muscle satellite cells, and endogenous bFGF also has obvious effect on muscular repair.But whether bFGF gene transfection has the same effect on extraocular muscle satellite cells is unclear.OBJECTIVE: The goal of this study was to investigate the effect of bFGF gene transfection on the bio-behavior of rat extraocular muscle satellite cells.DESIGN: Single sample observation.SETTING: Department of Ophthalmology, Qingdao University Medical College.MATERIALS: Primary rat extraocular muscle satellite cells were cultured (purity ＞ 90%). Human PEGFP-N3-bFGF eukaryotic expression vector was successfully constructed (reported in other papers).METHODS: This study was carried out in the Central Laboratory of Qingdao University Medical College between September 2005 and December 2006. Experimental intervention and grouping: During the experiment, 3 groups were divided: Experimental group, in which, recombinant PEGFP-N3-bFGF was used for transfection; Control group A, in which, empty-load PEGFP-N3 was used for transfection; Control group B: in which, only F 10 medium (0.1 volume fraction of fetal bovine serum)was used for transfection. Recombinant PEGFP-N3-bFGF plasmid was used to transfect rat extraocular muscle satellite cells cultured in vitro by liposome-mediated transgenic technology. Experimental evaluation: bFGF expression was observed by immubohistochemical method; Transfection efficiency was detected with fluorescence microscope; The protein secretion of bFGF of satellite cells in each group was detected by SBC-ELISA method on the 1st, 3rd, 5th, 9th, 11th, 13th, 15th, 21st and 28th days of culture; The proliferation of rat extraocular muscle satellite cells in each group was detected by methyl thiazolyl tetrazolium(MTT) method; Creatine kinase (CK) activity of cells in each group was determined according to the A value of some standard whose concentration was known.MAIN OUTCOME MEASURES: ① Transfection efficiency of bFGF gene to rat extraocular muscle satellite cells cultured in vitro and bFGF gene expression after transfection; ②bFGF protein secretion after transfection, and effect of bFGF gene transfection on the growth and proliferation of extraocular muscle satellite cells.RESULTS: ① Transfection efficiency of bFGF gene to rat extraocular muscle satellite cells cultured in vitrowas (42.8±1.2)%. ② Immunohistochemical detection showed positive reaction. ②Transfected cells could secrete bFGF protein,which was the highest on the 5th day (662.935 ng/L). ④ The proliferation activity of transfected cells was obviously enhanced, and its A value was significantly higher than that of control group at the same time point (P ＜ 0.05). ⑤CK value was higher than that of the control group from the 5th day after transfection to the end (P ＜ 0.01).CONCLUSION: bFGF gene transfering into rat extraocular muscle satellite cells can make extraocular muscle satellite cells to secrete bFGF, promote cell proliferation, survival and differentiation.