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The damage caused by space microgravity environment to the body systems of astronauts directly affects their work efficiency.This paper reviewed previous studies on the effects of space microgravity environment and ground simulated microgravity environment on cognition and emotion, potential mechanisms and interventions. It was found that a microgravity environment led to dysfunction in learning, memory, spatial orientation and other aspects, and caused anxiety and depression. The mechanisms of cognitive and emotional impairment associated with microgravity environment are complex, including neuronal damage, brain structure changes, neurotransmitter disorders, synaptic dysfunction, oxidative stress injury, and energy metabolism disorders. Pharmacological approaches such as natural extracts, physical interventions such as repetitive transcranial magnetic stimulation, and new therapies such as probiotics were expected to reduce cognitive impairment and mood disorders caused by microgravity exposure. With the development of aerospace medicine in China, the potential mechanism and interventions of microgravity environment on cognitive and emotional impairment remain to be further studied.
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Microgravity is a typical feature of the space. A large number of space flights and foundation simulation experiments have shown that cells show typical biological characteristics of aging, such as reduced cell proliferation and cell cycle arrest under microgravity or simulated microgravity. However, the molecular mechanism by which microgravity or simulated microgravity affects cellular senescence is not well understood. Understanding the mechanism controlling cellular senescence induced by microgravity environment is helpful for exploring anti-aging strategies and targeted interventions in space. In recent years, domestic and foreign scholars have carried out a number of researches and explorations on the effect of microgravity and simulated microgravity on cellular senescence as well as the related mechanisms. In this review, the latest research progress of this filed was summarized.
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@#AIM: To observe changes in the flash electroretinogram(ERG)and retinal microcirculation in mice suspended by their tails, an animal model that simulates cephalad movement of bodily fluids under conditions of microgravity.<p>METHODS: Thirty-six adult male C57BL/6J mice(36 eyes)were randomly divided into three experimental groups and three control groups. Mice in the experimental groups were tail-suspended for 15d(Group one), tail-suspended for 30d(Group two), or tail-suspended followed by returning to normal position for 30d(Group three). Three control groups were similarly fixed with a harness but kept in the normal position for corresponding periods of 15, 30, and 60d. The mice were immediately examined using scotopic ERG(including oscillatory potentials \〖OPs\〗)and fundus fluorescein angiography(FFA)<i>in vivo</i>, and subsequently sacrificed to analyze the retinal histology(methods including immunohistochemistry and TUNEL staining)<i>in vitro</i>. Independent sample <i>t</i>-test was used for data comparison between the same time-point groups.<p>RESULTS: Following 15-days' tail-suspension, scotopic ERG showed a decline in OPs, but not in the b-wave; the second OP(O2)showed an amplitude of 197±33μV, which was about 60% of the control level(<i>t</i>=-5.938, <i>P</i><0.001). Following 30-days' tail-suspension, ERG recovered, with O2 showing an average value of 264±39μV; when compared to the corresponding control group(308±41μV), no significant difference was observed(<i>t</i>=-1.887, <i>P</i>>0.05). Morphologically, only the 15-days' tail-suspended mice showed FFA with microvascular dilation and tortuosity. Rhodopsin and cone-opsin were almost normal and no apoptotic-positive signals were detected in the retinas of the three tail-suspended groups.<p>CONCLUSION: Simulating cephalad shifting of bodily fluids as under microgravity, using short-term tail-suspension can affect rodent ERG and retinal microcirculation; however, the change is reversible with no obvious permanent injury observed in the retinas.
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Objective To study the effect of simulated microgravity on activity of the store-operated calcium (SOC) channels in osteocytes and its possible mechanism, so as to elucidate the potential mechanism of weightlessness bone loss. Methods Osteocytes (MLO-Y4) as the experimental subjects were divided into simulated microgravity (SM) group and normal gravity group (CON). After rotating for 24 h and 48 h, confocal microscope was used to detect the intracellular calcium ion concentration level to reflect activity of the SOC channels after thapsigargin (TG)-induced endoplasmic reticulum (ER) depletion. Immunofluorescence staining was used to observe the distribution of ER membrane protein IP3R and spectrin membrane skeleton, in order to preliminarily explore the possible mechanism of functional changes of SOC channels. Results During the period of calcium release from ER, ［Ca2+］i had no significant difference between SM group and CON group for 24 h and 48 h; while during the period of extracellular calcium influx by SOC channels, ［Ca2+］i of SM group had significant differences in the first 4 minutes for 24 h, as well as in the whole time for 48 h. Compared with CON group, the spectrin membrane skeleton of SM group was gathered at the rim of membrane, while ER membrane protein IP3R of SM group was gathered at the nuclear envelope of ER. These two tendencies were more obvious for 48 h. Conclusions The stimulated microgravity could inhibit activity of SOC channels in osteocytes. Changes in the distribution of the spectrin membrane skeleton and ER membrane protein IP3R under the simulated microgravity might reduce the activity of SOC channels by affecting the conformation coupling process between the membrane and ER.
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In this study, we aim to investigat the effect of microgravity on osteoblast differentiation in osteoblast-like cells (MC3T3-E1). In addition, we explored the response mechanism of nuclear factor-kappa B (NF-κB) signaling pathway to "zero- " in MC3T3-E1 cells under the simulated microgravity conditions. MC3T3-E1 were cultured in conventional (CON) and simulated microgravity (SMG), respectively. Then, the expression of the related osteoblastic genes and the specific molecules in NF-κB signaling pathway were measured. The results showed that the mRNA and protein levels of alkaline phosphatase (ALP), osteocalcin (OCN) and type Ⅰ collagen (CoL-Ⅰ) were dramatically decreased under the simulated microgravity. Meanwhile, the NF-κB inhibitor α (IκB-α) protein level was decreased and the expressions of phosphorylation of IκB-α (p-IκB-α), p65 and phosphorylation of p65 (p-p65) were significantly up-regulated in SMG group. In addition, the IL-6 content in SMG group was increased compared to CON. These results indicated that simulated microgravity could activate the NF-κB pathway to regulate MC3T3-E1 cells differentiation.
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Animals , Mice , 3T3 Cells , Cell Differentiation , NF-kappa B , Physiology , Osteoblasts , Signal Transduction , Weightlessness SimulationABSTRACT
Objective: To investigate the effects of RCCS simulated microgravity on the metabolism of the human keratinocyte cell line HaCaT. Methods: The rotary cell culture system (RCCS) was used to simulate the microgravity environment, and HaCaT cells were cultured in vitro and divided randomly into simulated microgravity group (SMG) and normal gravity group (NG). The two group HaCaT cells were collected respectively after 1 d, 2 d and 3 d culture, and the samples were analyzed by LC/MS metabolomics. The differential metabolites between the SMG and NG cells were identified with partial least squares discriminant analysis ((O)PLS-DA), and the data were input into the KEGG database for the construction and functional analysis of metabolic pathways. Results: Comparing to NG cells, after 1 d culture, there were 74 different metabolites in SMG cells, among which 16 were up-regulated and 58 were down-regulated; after 2 d culture, there were 89 different metabolites, among which 15 were up-regulated and 74 down-regulated; after 3d culture, there were 100 different metabolites, of which 23 were up-regulated and 77 were down-regulated. The differentially expressed 49 metabolites (VIP>1 and P<0.05) after 3 d were set as target metabolites, within which the sphingosine, glutamate, and docosapentaenoic acid were down-regulated, and dehydrated sorbitol was up-regulated. KEGG analysis indicated that the metabolic pathways involved were amino acid metabolism, lipid metabolism, cell proliferation and apoptosis, substance transport, catabolism, and signal transduction. Conclusion: RCCS simulated microgravity may have significant impacts on keratinocyte metabolism mainly involving metabolites such as sphingolipids and glutamate as well as the related signaling pathways.
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To study the effect of microgravity on peripheral oxygen saturation (SpO ) in rats, tail-suspended rats were applied to simulate microgravity environment. SpO and arterial oxygen saturation (SaO ) were measured by pulse oximeter and arterial blood gas analyzer (ABGA) respectively on the 14th day, 21st day and 28th day in tail-suspended group and control group. Paired -test shows that SpO was significantly lower than SaO in tail-suspended group on the 14th day ( < 0.05), the 21st day ( < 0.05) and the 28th day ( < 0.01). The ANOVA results shows that modeling time had significant effect on SpO value but no effect on SaO value in tail-suspended group. These results indicate that pulse oximeter may be not suitable for oxygen saturation test in microgravity environment.
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<p><b>PURPOSE</b>Microgravity is known to cause endothelium dysfunction in astronauts returning from spaceflight. We aimed to reveal the regulatory mechanism in alterations of human endothelial cells after simulated microgravity (SMG).</p><p><b>METHODS</b>We utilized the rotary cell culture system (RCCS-1) to explore the subsequent effects of SMG on human umbilical vein endothelial cells (HUVECs).</p><p><b>RESULTS</b>SMG-treated HUVECs appeared obvious growth inhibition after return to normal gravity, which might be attributed to a set of responses including alteration of cytoskeleton, decreased cell adhesion capacity and increased apoptosis. Expression levels of mTOR and its downstream Apaf-1 were increased during subsequent culturing after SMG. miR-22 was up-regulated and its target genes SRF and LAMC1 were down-regulated at mRNA levels. LAMC1 siRNAs reduced cell adhesion rate and inhibited stress fiber formation while SRF siRNAs caused apoptosis.</p><p><b>CONCLUSION</b>SMG has the subsequent biological effects on HUVECs, resulting in growth inhibition through mTOR signaling and miR-22-mediated mechanism.</p>
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Humans , Apoptosis , Cell Proliferation , Cells, Cultured , Human Umbilical Vein Endothelial Cells , Physiology , Laminin , Genetics , MicroRNAs , Physiology , Weightlessness SimulationABSTRACT
The rotary cell culture system(RCCS)was used to simulate the microgravity environment, and FRTL-5 cells were divided into simulated microgravity group(SMG)and normal gravity group(NG). FRTL-5 cells were harvested after treatment for 6, 12, 24, and 36 h, the cell viability was measured by MTT assay, and the cells cycles were detected by flow cytometry. The ultrastructure of FRTL-5 cells was observed under laser confocal microscope with FITC-labeled technique. The MTT assay showed that the proliferation of FRTL-5 cells was significantly inhibited after RCCS treatment for 6, 12, 24, and 36h compared with NG(P<0.05), in which the most obvious effect was observed at 24h. The flow cytometry showed that the proportion of FRTL-5 cells at G1 stage in RCCS group was increased significantly after 6, 12, 24, and 36h compared with NG(P<0.05), while the proportion of FRTL-5 cells at S stage was decreased significantly(P<0.05)except that cultured with RCCS for 6 h. The proportion of FRTL-5 cells at G2/M stage was decreased in early phase(6-12 hours)of RCCS culture, with the lowest at 12h and transient increase at 24h of RCCS culture. The laser confocal microscope revealed that there were local microfilament depolymerization, tension fibers decrease, structure disorder, cellular pseudopodia reduction, and irregular shape among FITC-labeled FRTL-5 cells cultured with RCCS for 36h. (Chin J Endocrinol Metab, 2018, 34: 598-601)
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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.
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Objective To investigate the effects of simulated microgravity by rotary cell culture system (RCCS) on expression profiles of long non-coding RNA (lncRNA) in mouse fibroblasts L929 cell line.Methods L929 cells were cultured in vitro and randomly divided into simulated microgravity (SMG) group and normal gravity (NG) group.Each group had three samples,the rotator axis of SMG group was paralleled to the ground rotation,while the rotator axis of NG group was vertical to the ground rotation,and the speed of rotation was consistent for the two groups.The samples of two groups were collected on 7th day of culture and the total RNAs were extracted,labeled and hybridized in sequence.The lncRNA and mRNA were detected by Agilent Mouse lncRNA Chips respectively.Differentially expressed lncRNA were identified and then validated by RT-qPCR.GO and Pathway analysis were applied to determine the functional distribution of these target genes.The integration predictions of the lncRNA and mRNA co-expression had been proposed to refine the functional lncRNA-mRNA relationships.Results There were 238 differentially expressed lncRNAs including 134 lncRNAs up-regulated and 104 lncRNAs down-regulated,and 237 differentially expressed mRNAs including 53 mRNAs up-regulated and 184 mRNAs down-regulated significantly in mouse fibroblasts L929 cell line under simulated microgravity by RCCS.The RT-qPCR showed a high concordance with chip microarray results in 4 differentially expressed lncRNA.GO analysis showed that the differentially expressed lncRNAs were related to the biological processes such as negative regulation of megakaryocyte differentiation and negative regulation of wound healing.Pathway analysis showed that these target genes were related to the signal pathways of systemic lupus erythematosus and TGF-β.The lncRNA-mRNA co-expression networks were also established.Conclusion The simulated microgravity by RCCS could significantly affect the expression profiles of lncRNA and mRNA in mouse fibroblasts L929.The lncRNA target genes prediction and functional enrichment analysis based on gene chip technology may provide the theoretical basis for illustrating the mechanism and management of weightlessness stress injury.
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Objective To explore the changes in inflammatory reactions in tail-suspension mice infected by Klebsiella pneumoniae from spaceflight.Methods Tail suspension was used to simulate the physiological effects of microgravity.C57BL/6 mice were randomly divided into control (Con),control+K.pneumoniae T16-169 (Con+T16-169),tail suspension (TS) and tail suspension+K.pneumoniae T16-169 (TS+T16-169) groups.The level of inflammatory cytokines TNF-α,IL-6 and IL-1β mRNA in lung tissue and the plasma cytokine concentration were detected by RT-qPCR and xMAP technology,and HE staining was used to represent the morphological changes in lung tissue.Results Compared with the control group,the expression of inflammatory cytokines in lung tissue and plasma concentrations of all experimental groups were increased,and the difference in TS+T16-169 group was the most significant (P<0.01 or P<0.001).HE staining showed that the lung tissues in Con+T16-169 and TS+T16-169 groups were damaged in different degrees,and the damage of TS+T16-169 group was the most serious.Conclusion The K.pneumoniae from spaceflight significantly increases the expression of inflammatory cytokines in lung tissue and plasma concentrations after infecting tail-suspension mice,and induces more serious damages to the lung tissue,which suggests that inflammatory reactions can be increased in tail suspension mice infected by K.pneumoniae from spaceflight.
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Objective To investigate the synergistic effects of simulated microgravity and noise on the audito‐ry functions and corti organs in rats .Methods A total of 48 healthy rats were randomly divided into 4 groups (n=12):control group (Group A) ,microgravity only group (Group B) ,noise only group (Group C) and microgravity+noise group (Group D) .The microgravity environment was simulated by suspending the posterior limb using Morey-Holton method .The noise exposure was the simulation of the noise environment in spaceship including steady -state noise (72 ± 2) dB SPL and impulse noise up to 160 dB SPL .The control group was kept in normal conditions without any exposure .Auditory brainstem responses (ABRs) ,HE stainings ,immunofluorescence stainings and scanning electron microscopes (SEMs) were tested after 1week and 2 weeks exposure respectively (n=6) .Results The average of ABR threshold shifts of 2 weeks exposure were higher than those of 1 week in each group .Group D showed the highest ABRs (P<0 .01) .The HE stainings showed different degrees of injury in corti organs in all experimental groups ;which Group D being the most serious ,followed by Group C .The results of immunefluorescence in hair cells showed that swelling necrosis was the main damage of cochlear hair cell after 1 week's exposure .The swelling rate of Group D was the highest ,followed by Group C .Nucleus missing in hair cells was observed after 2 weeks'exposure . Group D had the highest missing rate and the main missing of Group B happened in the inner hair cells .SEM showed that the most serious damage of stereociliums in Group D ,followed by Group C ,then Group B .Conclusion The synergistic effects of simulated microgravity and noise lead to significant damage of the auditory function and cochlea Corti organs in rat .
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Objective To investigate the effects of simulated microgravity on the structure, expression of surface molecules of immune cells and the expression of cytokines in the spleen of rhesus monkey. Methods Fifteen rhesus monkeys were employed as the research objects, and randomly assigned into three groups (5 each): normal control (NC) group, simulated microgravity (SM) group and microgravity recovery (MR) group. A posture with head down for –10° was set for monkeys to simulate microgravity. All the rhesus monkeys were sacrificed under anesthesia after experiments completion. Spleen tissues were harvested and HE and immunohistochemically stained to observe the general structure of the spleen tissues in each group and detect the expressions of surface molecules (CD3, CD4, CD8, CD20 and CD68) in immune cells, and the expressions of related cytokines (IL-1, IL-5, IL-6, IL-17, IL-18, IL-22 and IL-23) on the splenic immune cells. Results Compared with the normal structure of spleen tissues in NC group, the dividing lines between red and white pulp were not clear, the white pulp and the periarteriolar lymphoid sheath were decreased, and the lymphocytes arranged disorder in SM group. The expressions of CD3, CD4 and CD20 decreased and of CD8 increased significantly in SM group (P<0.05). The production of IL-5 was significantly lower in SM group than in NC and MR groups (P<0.05). Conclusions Simulated microgravity may cause spleen tissue damage and throw an influence on the quantity of CD3+ T-cell, CD4+ T-cell, CD8+ T-cell and CD20+ B-cell in rhesus monkey. Homogeneously, the production of IL-5 is decreased in spleen of rhesus monkey under simulated microgravity. These effects may be related to the damage of immune system under simulated microgravity.
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Objective To study the effect of osgentide (OST) on proliferation of mouse preosteoblast MC3T3-E1 under simulated microgravity ( SMG ) .Methods Under normal conditions , cell proliferation was evaluated by MTT assay to screen an OST compound of an effective concentration after MC 3T3-E1 cells were treated with series OSTs .Furthermore, cell proliferation and cell cycle distribution of MC 3T3-E1 cells were analyzed after treatment with 1 nmol/L OST5 by MTT assay and by flow cytometry ( FCM) scanning under SMG .Results Under normal conditions , 1 nmol/L OST5 was able to significantly promote the proliferation of MC3T3-E1 cells (P<0.01).Under SMG, proliferation of MC3T3-E1 cells was significantly inhibited and more cells entered G 1 than under normal conditions (CN).The proportion of S phase of MC3T3-E1 cells after treatment with 1 nmol/L OST5 ( OST-SMG) for 3 d was higher than that of untreated MC 3T3-E1 cells under SMG,suggesting that OST5 could promote DNA synthesis ( P<0.05 ) .Conclusion OST5 facilitates the proliferation of MC3T3-E1 cells under SMG, which provides a basis for the use of OST5 in the prevention and treatment of bone loss relat-ed to microgravity .
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Objective To investigate the effect of simulated microgravity on the proliferation and differentiation of the human megakaryocyte cells in vitro. Methods The fourth generation rotating cell culture system (RCCS-4) was used to generate the simulated microgravity environment. The cell viability was assessed by trypan blue staining method. The proliferation of cells was assessed by cell counting method and CCK8 method. The CD41+/CD61+ cells rate and the cells cycle were detected by flow cytometry. The expression levels of thrombopoietin receptor (c-mpl) and transcription factors were detected with RT-PCR. Results After 24, 48, 72 h, culture under simulated microgravity resulted in a significant decrease in the cell number , proliferative activity, cells in the G2/M phase and levels of c-mpl mRNA expression in comparison with that under the normal gravity (P < 0.05). After 48 h and 72 h culture, CD41+/CD61+ cells ratio decreased and RUNX-1 mRNA expression was down-regulated in cells of the group SMG compared with that of the group NG (P < 0.05). Conclusion Microgravity can inhibit the proliferation and differentiation of human megakaryocyte cells in vitro. The mechanism may be that TPO/c-mpl pathway was inhibited by down regulating the expression of c-mpl which transcriptional inhibition lead to.
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<p><b>OBJECTIVE</b>To study the effect of Simulated Microgravity and its Associated Mechanism on Pulmonary Circulation in Rats).</p><p><b>METHODS</b>Rat tail-suspension model was used to simulate the physiological effects of microgravity and changes in pulmonary blood vessel morphology, pulmonary arterial and venous blood pressure, pulmonary vascular resistance, pulmonary vasomotoricity, as well as the regulation of pulmonary circulation by cytokines produced and released by the lung of rats were measured.</p><p><b>RESULTS</b>The walls of pulmonary blood vessels of rats were thickened, and the pulmonary artery was reconstructed with increased pulmonary vascular resistance. The pulmonary blood vessels of rats became more prone to dilation as contractions increased. Rat epithelial Adrenomedulin gene transcription and protein expression were upregulated. The level of basic fibroblast growth Factor of rat was also elevated.</p><p><b>CONCLUSION</b>Findings from the present study on rats revealed that the microgravity can affect pulmonary blood vessel structure, pulmonary arterial pressure, and pulmonary blood vessel self-regulation and cytokine production.</p>
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Animals , Male , Rats , Hemodynamics , Pulmonary Artery , Physiology , Pulmonary Circulation , Physiology , Rats, Wistar , WeightlessnessABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of simulated microgravity and carbon ion irradiation (CIR) on spermatogenic cell apoptosis and sperm DNA damage to the testis of male Swiss Webster mice, and assess the risk associated with space environment.</p><p><b>METHODS</b>Sperm DNA damage indicated by DNA fragmentation index (DFI) and high DNA stainability (HDS) was measured by sperm chromatin structure assay (SCSA). Apoptosis of spermatogenic cells was detected by annexin V-propidium iodide assay. Bax (the expression levels of p53) and proliferating cell nuclear antigen (PCNA) were measured by immunoblotting; p53 and PCNA were located by immunohistology.</p><p><b>RESULTS</b>HDS, DFI, apoptosis index, and the expression levels of p53 and Bax were detected to be significantly higher in the experimental groups (P<0.05) compared with those in the control group; however, the PCNA expression varied to a certain degree. p53- and PCNA- positive expression were detected in each group, mainly in relation to the spermatogonic cells and spermatocytes.</p><p><b>CONCLUSION</b>The findings of the present study demonstrated that simulated microgravity and CIR can induce spermatogenic cell apoptosis and sperm DNA damage. Sperm DNA damage may be one of the underlying mechanisms behind male fertility decline under space environment. These findings may provide a scientific basis for protecting astronauts and space traveler's health and safety.</p>
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Animals , Male , Mice , Apoptosis , Radiation Effects , Carbon , Cell Proliferation , Radiation Effects , DNA Damage , Heavy Ions , Immunohistochemistry , Random Allocation , Sperm Count , Spermatogenesis , Radiation Effects , Spermatozoa , Radiation Effects , Testis , Radiation Effects , Weightlessness SimulationABSTRACT
To explore whether an environment of weightlessness will cause damage to the reproductive system of animals, we used the tail-suspension model to simulate microgravity, and investigated the effect of microgravity on the tissue structure and function of the testis in sexually mature male rats. Forty-eight male Wistar rats weighing 200-250 g were randomly assigned to three groups (N = 16 each): control, tail traction, and tail suspension. After the rats were suspended for 7 or 14 days, morphological changes of testis were evaluated by histological and electron microscopic methods. The expression of HSP70, bax/bcl-2 and AR (androgen receptor) in testis was measured by immunohistochemistry. Obvious pathological lesions were present in the testis after the rats were suspended for 7 or 14 days. We detected overexpression of HSP70 and an increase of apoptotic cells, which may have contributed to the injury to the testis. The expression of AR, as an effector molecule in the testis, was significantly decreased in the suspended groups compared to control (P < 0.01). We also observed that, with a longer time of suspension, the aforementioned pathological damage became more serious and some pathological injury to the testis was irreversible. The results demonstrated that a short- or medium-term microgravity environment could lead to severe irreversible damage to the structure of rat testis.
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Animals , Humans , Male , Rats , Testis/ultrastructure , Weightlessness Simulation/adverse effects , /analysis , Hindlimb Suspension/adverse effects , Immunohistochemistry , Microscopy, Electron, Transmission , Random Allocation , Rats, Wistar , Receptors, Androgen/analysis , Testis/metabolism , Testis/pathology , /analysisABSTRACT
Mesenchymal stern cells (MSCs) were induced into a nucleus pulposus-like phenotype utilizing simulated microgravity in vitro in order to establish a new cell-based tissue engineering treatment for intervertebral disc degeneration.For induction of a nucleus pulposus-like phenotype,MSCs were cultured in simulated microgravity in a chemically defined medium supplemented with 0 (experimental group) and 10 ng/mL (positive control group) of transforming growth factor β1 (TGF-β1).MSCs cultured under conventional condition without TGF-β1 served as blank control group.On the day 3 of culture,cellular proliferation was determined by WST-8 assay.Differentiation markers were evaluated by histology and reverse transcriptase-polymerase chain reaction (RT-PCR).TGF-β1 slightly promoted the proliferation of MSCs.The collagen and proteoglycans were detected in both groups after culture for 7 days.The accumulation of proteoglycans was markedly increased.The RT-PCR revealed that the gene expression of Sox-9,aggrecan and type Ⅱ collagen,which were chondrocyte specific,was increased in MSCs cultured under simulated microgravity for 3 days.The ratio of proteoglycans/collagen in blank control group was 3.4-fold higher than positive control group,which denoted a nucleus pulposus-like phenotype differentiation.Independent,spontaneous differentiation of MSCs towards a nucleus pulposus-like phenotype in simulated microgravity occurred without addition of any external bioactive stimulators,namely factors from TGF-β family,which were previously considered necessary.