ABSTRACT
Objective To investigate the effects of simulated microgravity by RCCS on proliferation and cell cytoskeleton of human HaCaT keratinocyte. Methods The rotary cell culture system (RCCS) was used to simulate the microgravity environment, and human HaCaT keratinocytes were divided randomly(random number) into the simulated microgravity group (SMG) and normal gravity group (NG). HaCaT cells in the two groups were harvested respectively after 32, 36 and 42 h culture. The HaCaT cells proliferation and cycles were detected by flow cytometry, the concentration of hb-EGF in supernatant was detected by ELISA, and the cell cytoskeleton was observed after 42 hours' culture under laser confocal microscope with FITC-labeled technique. SPSS 23.0 statistical software was used for statistical analysis, and P <0.05 was considered statistically significant. Results The flow cytometry showed that the proportions of human HaCaT keratinocytes in G1 and G2/M phases were increased while the proportion of HaCaT cells in S stage was decreased significantly after 32, 36 and 42 h RCCSculture compared with those in the normal gravity group. The HaCaT cells in G1 stage were declined along with incubation time. ELISA results showed that the hb-EGF concentration in HaCaT supernatant under simulated microgravity culture for 24 and 36 h was lower than that in the normal control group (P<0.01). The laser confocal microscope revealed that the HaCaT fluorescence intensity was decreased,and there were disordered microfilaments, structural ambiguity, pseudopodia reduction and irregularshape among FITC-labeled HaCaT cells cultured 42 h in RSSC compared with the normal gravity group.Conclusions RCCS simulated microgravity environment could inhibit the cell cycle transformation and proliferation of human HaCaT keratinocyte, affect the keratinocyte-secreting function, and induce alterations of the cell cytoskeleton.
ABSTRACT
Human hepatocarcinoma cells, HepG2 were cultured onto biodegradable polyglycolic acid (PGA) polymer scaffolds, which were cultured in a rotating cell culture system (RCCS) to form a three-dimensional (3D) multicellular culture in vitro. The RCCS can simulate microgravity effects with low shear stress and well exchanging for gas. Then the growth characteristics and some mechanism of the cells in RCCS were detected by scanning electron microscopy (SEM), transmission electron microscopy (TEM), RT-PCR and flow cytometry (FCM). The results indicate that the cells grew well with polyhedron morphology and lots of microvilli, mitochondria and tight junctions in this system, which means that this system is useful for cells to form 3D structure to mimic cell status in vivo. The expression of some cell adhesion molecules (CAMs) were changed markedly, which are closely associated with cancer invasion and metastasis. The characters of increased expression of integrin ?1(CD29), CD44, intercellular adhesion molecule-1(CD54) and depressed expression of E-cadherin presumably show that the HepG2 cells cultured in RCCS could recur some characters of primary liver cancer in vivo, the capacity of invasion and metastasis. It is necessary for acquiring perfect and external results to select an appropriate research model for studying in vitro. This 3D culture in vitro under simulated microgravity can provide a useful and reasonable model for oncology, anticancer drugs research and other research.