Effects of simulated microgravity on angiogenesis of HUVECs examined by metabolic analysis

김희진,김성민,김윤곤,정재현 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

In this study, we developed angiogenesis model to examine endothelial sprouting behavior and metabolic expression level under microgravity. This model was assembled with human umbilical vein endothelial cells (HUVECs) and the cells were cultured on the surface of dextran microcarriers, and they were cultured in a rotary cell culture systems (RCCS) to stimulate under microgravity. After exposure to simulated microgravity, dextran microcarriers coated HUVECs were embedded fibrin gel, and then, we observed sprouting of HUVECs. In addition, by applying the LC-MS-based quantitative method, we monitored changes in the metabolic expression level in endothelial cells stimulated under the microgravity. Taken together, the results of this study will be highly useful in designing various angiogenesis models to recapitulate and further manipulate the tissue of interest in space environments.

미세중력 환경에 노출된 백서 심근 조직의 병리학적 변화

김현수,김윤화 한국항공운항학회 2012 한국항공운항학회지 Vol.20 No.3

Spaceflight induces a number of cardiovascular physiological alterations. To study adaptations to microgravity on Earth, the tail-suspended, hindlimb-unloaded rat model has been used to simulate the effects of microgravity. Despite the extensive use of this model to infer physiological adaptations of many organs to microgravity, little information has been obtained on the effect of tail suspension(TS) on cardiac adaptations in the rat. This study was aimed to investigate the effects of simulated microgravity on the rat myocardium using the TS model. Twenty-four male Sprague-Dawley rats were randomly assigned to 3experimental groups(1, 7 and 14 days of TS) and a control group. A microscopic examination was performed to assess histopathological changes in the myocardial morphology. The hearts from the control group, the 1 day-TS rats and the 7 day-TS rats revealed no evident abnormalities in cardiomyocyte size and morphology. At day 14 of TS,in contrast, the ventricular cardiomyocytes appeared more separated from each other and were slightly smaller in size compared with those of the control group. Also seen were scattered areas exhibiting focal disorganization of muscle fibers and some degenerating cardiomyocytes, of which the nuclei had become pyknotic or disappeared. In this study, we demonstrated that the ventricular cardiomyocytes underwent degeneration and atrophy at the microscopic level during exposure to simulated microgravity in TS rats.

미세중력 환경에 노출된 백서 심근 조직의 병리학적 변화

김현수 ( Hyun Soo Kim ),김윤화 ( Youn Wha Kim ) 한국항공운항학회 2012 한국항공운항학회지 Vol.20 No.3

Spaceflight induces a number of cardiovascular physiological alterations. To study adaptations to microgravity on Earth, the tail-suspended, hindlimb-unloaded rat model has been used to simulate the effects of microgravity. Despite the extensive use of this model to infer physiological adaptations of many organs to microgravity, little information has been obtained on the effect of tail suspension(TS) on cardiac adaptations in the rat. This study was aimed to investigate the effects of simulated microgravity on the rat myocardium using the TS model. Twenty-four male Sprague-Dawley rats were randomly assigned to 3experimental groups(1, 7 and 14 days of TS) and a control group. A microscopic examination was performed to assess histopathological changes in the myocardial morphology. The hearts from the control group, the 1 day-TS rats and the 7 day-TS rats revealed no evident abnormalities in cardiomyocyte size and morphology. At day 14 of TS,in contrast, the ventricular cardiomyocytes appeared more separated from each other and were slightly smaller in size compared with those of the control group. Also seen were scattered areas exhibiting focal disorganization of muscle fibers and some degenerating cardiomyocytes, of which the nuclei had become pyknotic or disappeared. In this study, we demonstrated that the ventricular cardiomyocytes underwent degeneration and atrophy at the microscopic level during exposure to simulated microgravity in TS rats.

국제우주정거장 화재안전 연구개괄

박설현(Seul-Hyun Park),황철홍(Cheol-Hong Hwang) 한국연소학회 2012 한국연소학회지 Vol.17 No.4

Due to a significant leap in the science and technology, the manned space exploration that has started with suborbital flights is now being expanded into the deep space. The space superpowers such as the U.S. and Russia have been making an effort to further develop the manned space technology. Among such technologies, the fire safety technology in microgravity has recolonized as one of the most critical factors that must be considered for the manned space mission design since the realistic fire broke out onboard the Mir station in 1997. In the present study, the flame characteristics such as flame ignition, shape, spread, and extinction that are critical to understand the fire behavior under microgravity conditions are described and discussed. The absence of buoyancy in microgravity dominates the mass transport driven by diffusiophoretic and thermophorectic fluxes (that are negligible in normal gravity) and influences the overall flame characteristics-flame ignition, shape, spread, and extinction. In addition, the cabin environments of the pressurized module (PM) including the oxygen concentration, ambient pressure, and ventilation flow(which are always coupled with microgravity condition during the ISS operation) are found to be the most important aspects in characterizing the fire behavior in microgravity.

Novel Angiogenic microball Assembled with Endothelial cells stimulated by Microgravity

김희진,안다희,정나슬,김윤곤,정재현 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

In this study, we developed novel angiogenesis model to examine endothelial sprouting behavior under microgravity. This model was assembled with human umbilical vein endothelial cells (HUVECs) and the cells were cultured on the surface of dextran microcarriers, and they were cultured in a rotary cell culture systems(RCCS) to stimulate under microgravity.. After exposure to simulated microgravity, dextran microcarriers coated HUVECs were embedded fibrin gel, and then, we observed sprouting of HUVECs. In addition, by applying the MALDI-MS-based quantitative method, we monitored changes in the metabolic expression level in endothelial cells stimulated under the microgravity. Taken together, the results of this study will be highly useful in designing various angiogenesis models to recapitulate and further manipulate the tissue of interest in space environments.

마이크로중력환경에서 사용 가능한 관성저울의 성능평가

장현진(Hyun-Jin Jang),이주희(Joo-Hee Lee),최재혁(Jae-Hyuk Choi),박설현(Seul-Hyun Park) 대한기계학회 2014 大韓機械學會論文集A Vol.38 No.12

중력이 거의 작용하지 않는 마이크로중력환경에서 소동물의 질량이 측정 가능한 고성능 관성저울을 개발하기 위해, 약 100g의 측정시료를 이용하여 관성저울의 핵심 디자인 파라미터인 로드셀의 응답특성을 평가하였다. 정확한 성능평가를 위해서 1.5초의 마이크로중력환경을 제공할 수 있는 15m 자유낙하탑을 활용하였으며, 살아 있는 동물의 질량을 측정해야 하는 점을 고려하여 측정시료의 감속 크기변화에 따른 로드셀의 응답특성를 파악하였다. 동일한 가속도로 가·감속되는 표준시료와 측정시료의 관성력 비의 분석결과 로드셀이 장착된 가속판이 평균 이동속도 0.5 m/s 이상으로 운동하는 경우에 한하여 설계 기준에 부합하는 것을 알 수 있었다. In an effort to develop and implement an inertial balance with high performance, the response characteristics of a load cell, which are some of the critical parameters for optimal system design, were evaluated using a sample object of approximately 100 g under microgravity conditions. To this end, a 15-m drop-tower was used to produce microgravity conditions, and the response characteristics of the load cell were investigated in terms of the variations in the magnitude of the deceleration of the sample object, noting that the mass of a living animal should be determined in microgravity. An analysis of the ratio of the inertial forces clearly demonstrated that the average velocity of a load cell plate should be higher than 0.5 m/s to meet the design requirements.

실험연구 : 생쥐(Mice)에서 하지무부하가 심혈관계 기능에 미치는 영향

이영복 ( Young Bok Lee ),박종택 ( Jong Taek Park ),임현교 ( Hyun Kyo Lim ),최재찬 ( Jae Chan Choi ),김순열 ( Soon Yul Kim ),조준현 ( Jun Hyun Cho ),이광호 ( Kwang Ho Lee ) 대한마취과학회 2007 Korean Journal of Anesthesiology Vol.53 No.2

Background: Orthostatic intolerance is a debilitating problem that can occur after prolonged bed-rest, exposure to microgravity, and in the elderly. This study examined the integrated cardiovascular response to baroreceptor activation in a hind-limb unweighing (HLU) mouse model of microgravity to test the hypothesis that both the pressor and contractility response are attenuated in HLU mice. Methods: C57BL/6 mice (25-30 g body wt, 8-10 wk old) were exposed to HLU for 2 weeks. A bilateral carotid artery occlusion and open-loop baroreceptor stimulus was performed to measure the myocardial contractile responses using a left ventricular micromanometer-conductance catheter in the mice. In isolated myocytes simultaneous sarcomere shortening and calcium transient were measured in response to increasing concentrations of the β-agonist isoproterenol. Results: In the controls, bilateral carotid artery occlusion increased the heart rate and mean arterial pressure. These responses were markedly attenuated in the HLU mice. A bilateral carotid artery occlusion also increased the slope of the end-systolic pressure volume relationship (Ees) by 70 ± 11% and the slope was markedly attenuated to 10 ± 8% in the HLU mice. Isoproterenol increased the sarcomere shortening in both control and HLU mice in a dose-dependent manner. However the contractile response to isoproterenol was significantly attenuated in the HLU mice than the controls. Conclusions: Both the pressor and myocardial contractile responses appear to be impaired in a mouse model of microgravity. (Korean J Anesthesiol 2007; 53: 222~8)

마이크로중력 비행 실험을 위한 연소실험장비의 구조해석

이종원,홍터기,남원식,이주희,김연규,박설현 조선대학교 공학기술연구원 2019 공학기술논문지 Vol.12 No.4

This study had developed a combustion experiment system for a cool flame research in microgravity environment. For the development of the system, various combustion experiment devices used on the ISS were reviewed, and the shape, size, thickness, and material of the combustion chamber were designed by the standard requirements based on the Korea Standard (KS) and Japan Industrial Standard (JIS). The system was loaded on a reduced-gravity aircraft (so-called, parabolic flight campaign) at Zero-G Corporation in the United States for the cool flame experiment. For the experiment in the aircraft which simulated microgravity environment, structural analysis of a combustion chamber under the condition of pressurized and depressurized cases using a finite elements method was carried out. Furthermore, the factor of safety for the combustion system in the aircraft where hyper-gravity (9G) occurred was calculated. It was confirmed that the system was structurally safe for parabolic flight experiment under microgravity.

Computation of Nonpremixed Methane-Air Diffusion Flames in Microgravity : Ⅰ. Profiles of Flame Temperature and Axial Velocity Ⅰ. 화염온도와 축방향 유속의 분포

Park, Woe-Chul 한국안전학회 2004 한국안전학회지 Vol.19 No.1

수치법을 검증하고 변형률과 연료농도가 무중력 확산화염 구조에 미치는 영향을 파악하기 위해, 무중력에서의 비예혼합 메탄-공기 대향류 화염의 구조를 FDS의 축대칭 모사로 조사하였다. 연료 중의 메탄 몰분율 x_m = 20, 50, 80%와 각각의 몰분율에서 변형률 a_g=20, 50, 90s^(-1)의 계산결과를 1차원 화염코드인 OPPDIF의 결과와 비교하였다. 축대칭 모사로 계산한 온도와 축방향 유속의 분포가 1차원 모사 결과와 잘 일치하였다. 화염의 두께와 위치, 정체점을 잘 예측함으로써 FDS를 넓은 범위의 변형률과 연료농도의 대향류 화염에 적용할 수 있음을 확인하였다. The structure of the nonpremixed methane-air counterflow flames in microgravity was investigated by axisymmetric simulation with Fire Dynamics Simulator (FDS) to evaluate the numerical method and to see the effects of strain rate and fuel concen ftation on the diffusion flame structure in microgravity. Results of IDS for the methane mole fiactions, x_m = 20, 50, and 80% in the fuel stream, and the global strain rates a_g = 20, 50, and 90s^(-1) for each methane mole fraction were compared with those of OPPDIF, an one-dimensional flamelet code. There was good agreement in the temperature and axial velocity profiles between the axisymmetric and one-dimensional computations. It was shown that IDS is applicable to the counterflow flames in a wide range of strain rate and fuel concentration by predicting accurately the flame thickness, flame positions and stagnation points.

Gap junction mediated regulation of osteocytes to osteoblastic alkaline phosphatase activity is independent of microgravity

Rui Meng,Li Xie 한국통합생물학회 2014 Animal cells and systems Vol.18 No.1

Decreased bone formation is one of the main causes of bone loss under microgravity. As a mechanical perceiver, osteocyte regulates bone formation by sending mechanical signals to osteoblast. However, the regulation of osteoblastic bone formation by osteocytes is less known so far under the microgravity conditions. The aim of this study was to investigate the regulation of bone formation/loss by detection of the osteocytic regulatory effects on the bone-specific alkaline phosphatase (ALP) activity of osteoblasts under altered gravitational environment. The altered gravitational environment was provided by a large gradient high magnetic field that could produce high magneto-gravitational environment (HMGE) and provided three apparent gravity levels (μg, 1g, and 2g). After the MLO-Y4 and 2T3 cells were cocultured in direct physical contact for 24 h and established gap junction intercellular communication under HMGE, a highly significant rapid increase in ALP activity was observed in μg, 1g, 2g, and control group (p < 0.001). Conversely, application of 50-μM beta-glycyrrhetinic acid gap junction inhibitor or remote coculture significantly decreased the ALP activity. There were no obvious differences of osteoblastic 2T3 ALP activity among μg, 1g, 2g, and control groups. Based on these findings, we interpreted that gap junction was probably the main route of osteoblastic ALP activity regulation by osteocyte. Gravity had no significant impact on the osteoblastic ALP activity regulated by osteocyte in a short period of time.