ObjectivesThe molecular mechanism of bone marrow mesenchymal stem cell (BMMSC) population growth and proliferation, induced by Isoleucyl-lysyl-valyl-alanyl-valine (IKVAV), was explored in this study.Materials and methodsIKVAV peptides were synthesized by the solid-phase method. Influence of IKVAV on BMMSC population growth and proliferation were investigated by assays of CCK-8, flow cytometry, real-time PCR and western blotting.ResultsIKVAV peptide was found to induce proliferation and proliferating cell nuclear antigen (PCNA) synthesis of BMMSC in a dose- and time-dependent manner. Cell cycle analysis showed that the proportion of IKVAV-treated BMMSC in S phase in was higher than controls. Western blot results suggested that mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signalling pathways were activated by IKVAV by enhancing phosphorylation levels of ERK1/2 and Akt in the BMMSCs. Meanwhile, phosphorylation levels of ERK1/2 and Akt were partially blocked by ERK1/2 inhibitor (PD98059) and Akt inhibitor (wortmannin), respectively.ConclusionsOur results demonstrated that IKVAV stimulated BMMSC population growth and proliferation by activating MAPK/ERK1/2 and PI3K/Akt signalling pathways. This study is the first to reveal an enhancement effect of IKVAV peptide on BMMSC at the signal transduction level, and the outcome could provide experimental evidence for application of IKVAV-grafted scaffolds in the field of BMMSC-based tissue engineering.

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High temperature behaviour of glass-vinyl ester stack liner at the operation temperature (20–121°C) was experimentally investigated by measurements on the small specimens and full scale specimens in this paper. Based on the stacking sequences of a typical glass-vinyl ester stack liner, three groups of small specimens were produced to evaluate the degradation of their tensile and compressive strength, the tensile modulus, and the flexural strength and modulus with increasing temperature, and one group of full scale specimens was prepared to measure their properties at room temperature. Furthermore, the ultimate axial tensile stress of a suspended glass-vinyl ester stack liner at various temperatures was derived according to the experimental results from the small specimens and full scale specimens. The high temperature behaviour of composites stack liner from the tests can be used as reference for determining the extreme operation temperature in coal-fired power plants.