Biomedical subjects

De-jun Cao

Publications and source records attributed to De-jun Cao.

3 recordsLinked to original sources

PubMed2004

[Preliminary study on in vitro tendon engineering using tenocytes and polyglycolic acids].

OBJECTIVE: To find out the feasibility of tendon engineering in vitro using expanded tenocytes and polyglycolic acids (PGA). METHODS: Tenocytes were isolated using tissue explant method and expanded in vitro. Tenocytes (20 x 10(6)) at the second passage were collected and then seeded onto PGA unwoven fibers to form a cell-scaffold construct in a shape of tendon. The constructs were cultured in DMEM with 20% FBS for 1 week. The cell-scaffold constructs were then cultured under constant tension generated by a U-shaped spring (n = 5), which served as experimental group, or cultured without tension (n = 4), which served as control group 1. PGA fibers alone were cultured (n = 3), which served as control group 2. Small fragments at the end of the constructs were harvested at 2, 4 and 6 weeks respectively for histological and immunohistochemistry (IHC) analysis. Six-week samples were also evaluated by transmission electron microscope (TEM) and mechanical test. RESULTS: No obvious difference was observed among the three groups at 2 weeks grossly and histologically as the constructs remained to be mainly undegraded PGA fibers. By 4 weeks, a neo-tendon was formed in the experimental group and control group 1 grossly, and histology and IHC revealed the formation of collagen fibers. In contrast, PGA fibers alone in control group 2 were mostly degraded. At 6 weeks, tendons of control group 1 were much thicker [(2.55 +/- 0.18) mm in diameter] than those of experimental group [(1.44 +/- 0.13) mm in diameter]. Periodical striae were observed in collagen fibers of experimental group and control group 1 by TEM. However, histology of tendons in experimental group revealed longitudinally aliened collagen fibers, which resembled the structure of normal tendon more closely than that of control group 1 tendons. Furthermore, the maximum tensile stress (N/mm(2)) of experimental group (1.107 +/- 0.327) was greater than that of control group 1 (0.294 +/- 0.138) (P < 0.05). CONCLUSION: It is possible to use an engineering to construct tendon tissue in vitro. Periodical strain generated by bioreactor may be the optimal mechanical stimulation, which is currently under investigation.

Animals↗

PubMed2004

[Experimental study on in vitro lamina propria engineering using oral fibroblast and polyglycolic acids].

PURPOSE: This study investigated the feasibility of lamina propria engineering in vitro using expanded oral fibroblast(OFC) and Polyglycolic Acids (PGA). METHODS: OFC were isolated by tissue explant method and expanded in vitro. OFC (20x10(6)) of 3rd passage were collected and then seeded onto PGA unwoven fibers to form a cell-scaffold. The constructs were cultured in DMEM +10% FBS. The cell-scaffold constructs were observed continuously by microscope. Small fragments were harvested at 1 week for electromicroscope, histological and RT-PCR analysis. RESULTS: At the sixth day, a neo-lamina propria was formed. HE and Masson stain revealed the formation of collagen fibers. RT-PCR revealed the new forming collagen was mainly type I collagen. CONCLUSION: lamina propria tissue is possible to engineer in vitro using oral fibroblast and polyglycolic acids. At this basis, we can construct bi-layer tissue engineering oral mucosa in the further research.

Fibroblasts↗

PubMed2002

[Effects of anti-ABL tyrosine kinase intrabody on the growth of K562 cells in nude mice].

OBJECTIVE: To study the effects of anti-ABL tyrosine kinase intrabody on the growth of human chronic myelogenous leukemia (CML) cells in nude mice. METHODS: A recombinant retroviral vector MSCV-ibE-IRES-eGFP was constructed to express intracellular single-chain antibody (intrabody) against ABL tyrosine kinase domain in CML cells. K562 cells were transduced with the retrovirus, eGFP+ cells were then selected by fluorescence-activated cell sorting (FACS). The intrabody mRNA expression was determined by reverse transcription (RT)-polymerase chain reaction (PCR). BCR/ABL and c-ABL protein tyrosine kinase (PTK) activity in the cells was examined. Transduced cells and control group K562 cells were transplanted into nude mice respectively and the tumor sizes were dynamically observed. RESULTS: K562-ibE cell was obtained. Expression of the BCR/ABL and c-ABL protein tyrosine kinase activity of harvested K562-ibE cells were markedly inhibited. At 14, 21 and 28 days after cell injection, the tumor volumes of experimental mice were obviously smaller than that of control mice, about one half of the control groups (P < 0.05). CONCLUSION: The growth of K562-ibE cells was significantly inhibited in vivo. It is possible that inhibition of the BCR/ABL protein tyrosine kinase activity by the intrabody blocked BCR/ABL signal transduction pathway, promoted apoptosis and reduced tumorigenicity of K562 cells in vivo.

Animals↗