Aligned Fibrous Scaffold Induced Aligned Growth of Corneal Stroma Cells in vitro Culture

To investigate the contribution of fibre arrangement to guiding the aligned growth of corneal stroma cells,aligned and randomly oriented fibrous scaffolds of gelatin and poly-L-lactic acid（PLLA） were fabricated by electrospinning.A comparative study of two different systems with corneal stroma cells on randomly organized and aligned fibres were conducted.The efficiency of the scaffolds for inducing the aligned growth of cells was assessed by morphological observation and 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl-tetrazolium bromide（MTT） assay.Results show that the cells cultured on both randomly oriented and aligned scaffolds maintained normal morphology and well spreading as well as long term proliferation.Importantly,corneal stroma cells grew high orderly on the aligned scaffold,while the cells grew disordered on the randomly oriented scaffold.Moreover,the cells exhibited higher viability in aligned scaffold than that in randomly oriented scaffold.These results indcate that electrospinng to prepare aligned fibrous scaffolds has provided an effective approach to the aligned growth of corneal stroma cells in vitro.Our findings that fiber arrangement plays a crucial role in guiding the aligned growth of cells may be helpful to the development of better biomaterials for tissue engineered cornea.

Alendronate affects osteoprotegerin/receptor of activator of nuclear factor κB-ligand expression in human marrow stroma cells in vitro

Objective To evaluate the effect of alendronate on osteoprotegerin(OPG)and receptor of activator of nuclear factor κB-ligand(RANKL)expression in human marrow stroma cells(hMSCs)in vitro.Methods hMSCs were isolated from human marrow,cultured in vitro,and randomly divided into two groups:alendronate group,hMSCs culture fluid containing 1×10-7mol/L alendronate;control group,no special treatment but culturing hMSCs in DMEM.Two weeks after treatment,the expressions of OPG and RANKL were evaluated by RT-PCR and Western blot.Results hMSCs became uniform spindle-shaped fibroblasts.As cells proliferated,they formed colonies and showed whirlpool arrangement.After one week’s treatment,hMSCs in alendronate group had reduced processes and gradually showed disc shape,which did not happen in control group but kept fibroblast shape and just increased in density.In RT-PCR,the ratio of OPG/RANKL in alendronate group and control group was 8.77±1.16 and 4.58±1.27,respectively.In Western blot,the ratio of OPG/RANKL in alendronate group and control group was 2.58±0.47 and 1.52±0.32,respectively.The ratio of OPG/RANKL was higher in alendronate group than in control group(P<0.01).Conclusion Alendronate enhances OPG expression and inhibits RANKL expression of hMSCs in vitro.

Effects of intermittent negative pressure on osteogenesis in human bone marrow-derived stroma cells

Objective： We investigated the effects of intermittent negative pressure on osteogenesis in human bone marrowderived stroma cells （BMSCs） in vitro. Methods： BMSCs were isolated from adult marrow donated by a hip osteoarthritis patient with prosthetic replacement and cultured in vitro. The third passage cells were divided into negative pressure treatment group and control group. The treatment group was induced by negative pressure intermittently （pressure： 50 kPa, 30 min/times, and twice daily）. The control was cultured in conventional condition. The osteogenesis of BMSCs was examined by phase-contrast mi- croscopy, the determination of alkaline phosphatase （ALP） activities, and the immunohistochemistry of collagen type 1. The mRNA expressions of osteoprotegerin （OPG） and osteoprotegerin ligand （OPGL） in BMSCs were analyzed by real-time polymerase chain reaction （PCR）. Results： BMSCs showed a typical appearance of osteoblast after 2 weeks of induction by intermittent negative pressure, the activity of ALP increased significantly, and the expression of collagen type I was positive. In the treatment group, the mRNA expression of OPG increased significantly （P〈0.05） and the mRNA expression of OPGL decreased significantly （P〈0.05） after 2 weeks, compared with the control. Conclusion： Intermittent negative pressure could promote osteogenesis in human BMSCs in vitro.

Murine corneal stroma cells suppress bone marrow-derived dendritic cells maturation in vitro

Background Prostaglandin E2 （PGE2） is a key modulator of dendritic cells （DCs） function, and cornea-derived transforming growth factor beta 2 （TGF-β2） promotes the generation of phenotypically and functionally immature DCs. Therefore, this study was carried out to investigate whether PGE2 is involved in the suppressive effect on DCs maturation mediated by corneal stroma cells （CSCs） and whether PGE2 and TGF-β2 have additive effects in this immunosuppressive mechanism. Methods Bone marrow-derived DCs （BM-DCs）, splenic T cells and CSCs culture supernatant were obtained from mice via various protocols. After that, the level of PGE2 in CSCs culture supernatant was analyzed by enzyme-linked immunosorbent assay. Then, immature BM-DCs pretreated by E-prostanoid 2 receptor antagonist AH6809 or dimethyl sulfoxide were induced to mature in the presence of lipopolysaccharide, with or without CSCs culture supernatant. In parallel experiments, neutralizing TGF-β2 antibody or normal goat IgG was added into the supernatant. Next, the cellular surface markers for DCs maturation, including CD80, CD86, and major histocompatibility complex class Ⅱ （MHC Ⅱ）, were analyzed by flow cytometry; the capability of stimulating the proliferation of T lymphocytes was evaluated by allogeneic mixed lymphocyte reactions and the function of endocytosis was assessed by fluorescein isothiocyanate-dextran uptake. Results Higher concentration of PGE2 was detected in CSCs culture supernatant than in the fresh medium. In addition, compared with control group, after treated with the supernatant in the mature stage, BM-DCs displayed lower expression of CD80, CD86 and MHC Ⅱ, lower T cell stimulatory capacity and higher endocytosis function. However, after the application of AH6809, BM-DCs partially regained T cell stimulatory capacity and expression of CD86 and MHC Ⅱ, but partially lost endocytic activity. Moreover, after the application of AH6809 and neutralizing TGF-β2 antibody, the result of statistical analysis indicated that there was a statistical difference of interaction in the expression of MHC Ⅱ and T cell stimulatory capacity. Conclusions PGE2 contributes to the suppressive effect on BM-DCs maturation mediated by CSCs in vitro, and PGE2 and TGF-β2 have additive effects on the immunosuppression of BM-DCs.

Cationic Liposome-mediated bcl-xl Gene Transfection into Human Keratocytes

The efficiency and safe range of LipofectamineTM2000 (LF2000)/bcl-xl applied in human keratocytes, the optimal ratio of LF2000/bcl-xl and the bcl-xl gene expression in human keratocytes were investiaged. By using trypan-blue staining, the effects of LF2000 and bcl-xl on the survival rate of the cultured human keratocytes were measured respectively. By using semi-quantitative RT-PCR, the efficiency and the expression of LF2000-mediated bcl-xl transfection into keratocytes were examined. The results showed that the survival rate of human keratocytes had no signficant change in the presence of LF2000 (20 μg/ml) or bcl-xl (10 μg/ml) for 24 h. LF2000 could effectively mediate the transfection of exogenous gene bcl-x1 into human keratocytes. The best transfection efficiency could be obtained when the ratio of bcl-xl/LF2000 was 1:8. One day after transfection, the positive cells for bcl-x1 could be detectable, and the positive rate reached the peak on the post-transfection day 3 (48.3 %), then gradually decreased. Fifteen days after transfection, there were few positive cells. It was suggested that LF2000 could effectively transfer the exogenous gene bcl-xl into human keratocytes without obvious toxicity during a concentration range. LF2000/bcl-xl may be likely to play an important role in gene therapy of human keratocytes.