Two kinds of gel materials were prepared from silk fibroin with polyepoxy compound at subfreezing temperature and higher temperature. In order to evaluate the feasibility of their application in biomaterials, we tested the cytotoxicity of silk fibroin gels by detecting the effect of the extracted liquid on the cell relative proliferation rate of L-929 mouse fibroblasts. The results indicated that both of the gel materials displayed high relative proliferation rate and grade 1 cytotoxicity, being in the allowed range of medical application. The cytotoxicity tests on polyepoxy compound and glutaraldehyde were conducted too, and the cytotoxicity of polyepoxy compound was obviously lower than that of glutaraldehyde. Polyepoxy compound can be used as a more safe cross-link reagent for silk fibroin modification.
Animals ; Biocompatible Materials ; chemistry ; Bombyx ; chemistry ; Cross-Linking Reagents ; chemistry ; Fibroblasts ; drug effects ; Fibroins ; chemistry ; Gels ; chemical synthesis ; toxicity ; Mice ; Polyethylene Glycols ; chemistry ; Temperature

Aim To explore the effects of chrysin on endothelial dysfunction induced by acute high glucose.Methods ① The effects of chrysin on normal isolated aortic at contraction induced by PE and on endothelial dysfunction induced by high glucose were tested in the following medium: normal group,chrysin group;normal-glucose group: glucose 11mmol·L-1 in Krebs' solution;high-glucose group: glucose 44 mmol·L-1 in Krebs' solution;mannitol group: mannitol 33 mmol·L-1 in Krebs' solution and chrysin group: 44 mmol·L-1 Glu+chrysin 1.0 μmol·L-1 in Krebs' solution.② The effects of chrysin on HUVEC cell viability after incubated in high glucose were observed in the following groups: normal-glucose group: glucose 5.5 mmol·L-1 in culture solution;high-glucose group: glucose 33.3 mmol·L-1 in culture solution;mannitol group: mannitol 27.8 mmol·L-1 in culture solution and chrysin group: chrysin(25,50 μmol·L-1)in culture solution.And the NO release was also testd in these groups.Results ① Chrysin could induce vaso-dilation in a dose-dependent manner at normal glucose.The Emax was(58.94±9.61)％,and the EC50 value was 51.9 μmol·L-1.After incubating the aortic rings with high glucose(44 mmol·L-1)for 4 h,there were significant differences in ACh-induced vascular relaxation between the normal glucose group and the high glucose group.The Emax was(32.12±3.92)％and the EC50 value was 78.0 μmol·L-1 of high glucose group(P<0.01).The endothelium-independent relaxation induced by SNP was not significantly different between the two groups.And chrysin(1.0 μmol·L-1)could reverse the decline of ACh-induced vasorelaxation response induced by high glucose(44 mmol·L-1).The Emax was(70.7±3.87)％and the EC50 value was 0.852 μmol·L-1.② The cell viability of HUVEC was depressed after incubated in high glucose,and chrysin could reverse the decline in a concentration-dependent way.And chrysin in defferent concentrations could increase the cell NO release.Conclusion Chrysin could prevent the acute high glucose-induced vascular endothelial dysfunction and could increase the NO release.

Recent researches about the application of silk fibroin in cell culture suggested that silk fibroin displayed high rate of cell attachment and growth in vitro culture of most kinds of cells, equivalent to collagen. So silk fibroin can be used for cell scaffold material of tissue engineering, and can be applied to several fields such as tissue engineering of skin, cartilage and blood vessel. The related researches and the prospect of the application of silk fibroin in cell scaffold of tissue engineering are reviewed in this paper.
Animals ; Biocompatible Materials ; Cell Adhesion ; Cell Culture Techniques ; Fibroins ; chemistry ; Humans ; Silk ; chemistry ; Tissue Engineering ; Tissue Scaffolds

Background Retinal pigment epithelium (RPE) cell transplantation is the primary means of human trial for the treatment of retinal degeneration.Induced pluripotent stem cells (iPSCs) will become an important source for cell transplantation.In addition,iPS-RPE cells may provide a personalized treatment platform for the patient's own cells treatment.Objective This study was to evaluate the feasibility of human fibroblasts differentiate toward iPSCs from retinitis pigmentosa (RP) patients and toward iPSC-RPE cells from non-RP individual by retroviral transfection of Oct4,Sox2,c-Myc and KLF4 genes.Methods Human thigh skin tissues were obtained from a RP patient with hotspot mutation of SNRNP200 p.S1087L and individual without SNRNP200 p.S1087L mutation,respectively,with the size 2 c m×3 cm.Human dermal fibroblasts were isolated and cultured by trypsin digestion and explant method.The fibroblasts were transfected by a series of retrovirus and cultured by human embyonic cellconditioned medium to generate and induce iPSCs,and then the iPSCs were identified by morphology,alkaline phosphatase (AP) staining and immunofluorescence assay of specific markers of pluripotent stem cells.iPSCs suspension were injected into SCID mouse to observe the tumorigenesis.The iPSCs from non-RP subject were induced to differentiate toward iPS-RPE cells by embryonic body (EB) inducing method,and iPS-RPE cells were identified by detecting the expression of RPE65,zonula occludens protein 1 (ZO-1) and lecithin retinol acyltransferase (LRAT).Results Cultured human dermal fibroblasts showed fusiform or polygon shape and intercellular close arrangement,and Vimentin was positively expressed in the cells.Small cell colonies were harvested 5-7 days after infected by retroviruses,and the morphology changed from spindle into round mass.The hESC-like iPSCs clonies appeared 20 days after cultivation,and the positive expressions of hESC-specific surface antigens including SSEA3,SSEA4,TRA-1-60,TRA-1-81 and Nanog were found in the cells 25-30 days after cultivation,and the positive staining of AP was obtained 12 weeks after cultivation.A teratoma was formed at the injection site of iPSCs suspension in SCID mouse.Immunofluorescence technique showed that RPE cell-specific proteins including RPE65,ZO-1 and LRAT proteins were positively expressed in iPS-RPE cells at 30 days after differentiation.Conclusions Mutation SNRNP200 p.S1087L of RP patient-specific iPSCs can be induced from human dermal fibroblast by retrovirus infection method.The function and morphology of the iPSCs were similar to hESCs.Human iPSCs cell line generated from the dermal fibroblasts of non-RP individuals can differentiate into iPS-RPE cells.

Metabolic-associated fatty liver disease (MAFLD), which is previously known as non-alcoholic fatty liver disease (NAFLD), represents a major health concern worldwide with limited therapy. Here, we provide evidence that ferroptosis, a novel form of regulated cell death characterized by iron-driven lipid peroxidation, was comprehensively activated in liver tissues from MAFLD patients. The canonical-GPX4 (cGPX4), which is the most important negative controller of ferroptosis, is downregulated at protein but not mRNA level. Interestingly, a non-canonical GPX4 transcript-variant is induced (inducible-GPX4, iGPX4) in MAFLD condition. The high fat-fructose/sucrose diet (HFFD) and methionine/choline-deficient diet (MCD)-induced MAFLD pathologies, including hepatocellular ballooning, steatohepatitis and fibrosis, were attenuated and aggravated, respectively, in cGPX4-and iGPX4-knockin mice. cGPX4 and iGPX4 isoforms also displayed opposing effects on oxidative stress and ferroptosis in hepatocytes. Knockdown of iGPX4 by siRNA alleviated lipid stress, ferroptosis and cell injury. Mechanistically, the triggered iGPX4 interacts with cGPX4 to facilitate the transformation of cGPX4 from enzymatic-active monomer to enzymatic-inactive oligomers upon lipid stress, and thus promotes ferroptosis. Co-immunoprecipitation and nano LC-MS/MS analyses confirmed the interaction between iGPX4 and cGPX4. Our results reveal a detrimental role of non-canonical GPX4 isoform in ferroptosis, and indicate selectively targeting iGPX4 may be a promising therapeutic strategy for MAFLD.