Effect of 15 days -6° head-down bed rest on microbial communities of supragingival plaque in young men.

Introduction: The microgravity environment astronauts experience during spaceflight can lead to an increased risk of oral diseases and possible changes in oral microecology. In this study, we aimed to assess changes in the microbial community of supragingival plaques to explore the effects of spaceflight microgravity environment on oral microecology. Methods: Sixteen healthy male volunteers were recruited, and supragingival plaque samples were collected under -6° head-down bed rest (HDBR) at five-time points: day 1 before HDBR; days 5, 10, and 15 of HDBR; and day 6 of recovery. Bacterial genomic DNA was sequenced using gene sequencing technology with 16S ribosomal ribonucleic acid V3-V4 hypervariable region amplification and the obtained data were analyzed bioinformatically. Results: Alpha diversity analysis showed a significant increase in species richness in supragingival plaque samples on day 15 of HDBR compared with that at pre-HDBR. Beta diversity analysis revealed that the community composition differed among the groups. Species distribution showed that, compared with those at pre-HDBR, the relative abundances of Corynebacterium and Aggregatibacter increased significantly during HDBR, while those of Veillonella, Streptococcus, and Lautropia decreased significantly. Moreover, compared with those at pre-HDBR, the relative abundance of Leptotrichia increased significantly on day 6 of recovery, whereas the relative abundances of Porphyromonas and Streptococcus decreased significantly. Network analysis showed that the interaction relationship between the dominant genera became simpler during HDBR, and the positive and negative correlations between them showed dynamic changes. Phylogenetic investigation of communities by reconstruction of unobserved states analysis showed that the amino acid metabolism function of plaque microorganisms was more enriched during HDBR. Discussion: In summary, in a 15-day simulated microgravity environment, the diversity, species distribution, interaction relationship, and metabolic function of the supragingival plaque microbial community changed, which suggests that microgravity may affect the oral microecosystem by changing the balance of supragingival plaque microbial communities and further leading to the occurrence and development of oral diseases.

Sleep-Monitoring Technology Progress and Its Application in Space.

INTRODUCTION: Sleep is an indispensable physiological phenomenon. The complexity of sleep and the time it occupies in human life determine that its quality is positively correlated with human health. Since polysomnography was used in spaceflight in 1967, the sleep problem during astronaut flight has been studied in depth for more than 50 yr, and many solutions have been proposed, but astronauts have always had sleep problems during orbital flight. Insufficient sleep and changes in the rhythm of human sleep-wake activity will lead to disturbance of the human body's internal rhythm indicators, which will lead to psychological and emotional fluctuations and reduced cognitive ability, decision-making ability, teamwork, and work performance. NASA has identified operational errors due to sleep deprivation and altered circadian rhythms as an important risk factor in the key biomedical roadmap for long-term flight, so the importance of sleep monitoring in spaceflight is self-evident. On-orbit sleep-monitoring methods include both subjective and objective aspects. We review objective sleep-monitoring technology based on its application, main monitoring physiological indicators, intrusive advantages, and limitations. This paper reviews the subjective and objective sleep evaluation methods for on-orbit applications, summarizes the progress, advantages, and disadvantages of current ground sleep-monitoring technologies and equipment, and looks forward to the application prospects of new sleep-monitoring technologies in spaceflight.Zhang C, Chen Y, Fan Z, Xin B, Wu B, Lv K. Sleep-monitoring technology progress and its application in space. Aerosp Med Hum Perform. 2024; 95(1):37-44.

Short-term head-down bed rest microgravity simulation alters salivary microbiome in young healthy men.

Microgravity influences are prevalent during orbital flight and can adversely affect astronaut physiology. Notably, it may affect the physicochemical properties of saliva and the salivary microbial community. Therefore, this study simulates microgravity in space using a ground-based -6° head-down bed rest (HDBR) test to observe the effects of microgravity on oral salivary secretion function and the salivary microbiome. Sixteen healthy young male volunteers were recruited for the 15-day -6° HDBR test. Non-stimulated whole saliva was collected on day 1 (pre-HDBR), on days 5, 10, and 15 of HDBR, and day 6 of recovery. Salivary pH and salivary flow rate were measured, and the V3-V4 region of the 16S rRNA gene was sequenced and analyzed in 80 saliva samples. The results showed that there were no significant differences in salivary pH, salivary flow rate, and alpha diversity between any two time points. However, beta diversity analysis revealed significant differences between pre-HDBR and the other four time points. After HDBR, the relative abundances of Actinomyces, Parvimonas, Peptostreptococcus, Porphyromonas, Oribacterium, and Capnocytophaga increased significantly, whereas the relative abundances of Neisseria and Haemophilus decreased significantly. However, the relative abundances of Oribacterium and Capnocytophaga did not recover to the pre-HDBR level on day 6 of recovery. Network analysis revealed that the number of relationships between genera decreased, and the positive and negative correlations between genera changed in a complex manner after HDBR and did not reach their original levels on day 6 of recovery. PICRUSt analysis demonstrated that some gene functions of the salivary microbiome also changed after HDBR and remained significantly different from those before HDBR on day 6 of recovery. Collectively, 15 days of -6° HDBR had minimal effect on salivary secretion function but resulted in significant changes in the salivary microbiome, mainly manifested as an increase in oral disease-related bacteria and a decrease in oral health-related commensal bacteria. Further research is required to confirm these oral microbial changes and explore the underlying pathological mechanisms to determine the long-term effects on astronauts embarking on long-duration voyages to outer space.

Hepatic metabolite responses to 4-day complete fasting and subsequent refeeding in rats.

Background: Fasting has been widely used to improve various metabolic diseases in humans. Adaptive fasting is necessary for metabolic adaptation during prolonged fasting, which could overcome the great advantages of short-term fasting. The liver is the main organ responsible for energy metabolism and metabolic homeostasis. To date, we lack literature that describes the physiologically relevant adaptations of the liver during prolonged fasting and refeeding. For that reason, this study aims to evaluate the response of the liver of Sprague-Dawley (SD) rats to prolonged fasting and refeeding. Methods: Sixty-six male SD rats were divided into the fasting groups, which were fasted for 0, 4, 8, 12, 24, 48, 72, or 96 h, and the refeeding groups, which were refed for 1, 3, or 6 days after 96 h of fasting. Serum glucose, TG, FFA, ß-hydroxybutyrate, insulin, glucagon, leptin, adiponectin and FGF21 levels were assessed. The glucose content, PEPCK activity, TG concentration and FFA content were measured in liver tissue, and the expression of genes involved in gluconeogenesis (PEPCK and G6Pase), ketogenesis (PPARα, CPT-1a and HMGCS2) and the protein expression of nutrient-sensing signaling molecules (AMPK, mTOR and SIRT1) were determined by RT-qPCR and western blotting, respectively. Results: Fasting significantly decreased the body weight, which was totally recovered to baseline after 3 days of refeeding. A 4-day fast triggered an energy metabolic substrate shift from glucose to ketones and caused serum hormone changes and changes in the protein expression levels of nutrient-sensing signaling molecules. Glycogenolysis served as the primary fuel source during the first 24 h of fasting, while gluconeogenesis supplied the most glucose thereafter. Serum FFA concentrations increased significantly with 48 h of fasting. Serum FFAs partly caused high serum ß-hydroxybutyrate levels, which became an important energy source with the prolongation of the fasting duration. One day of refeeding quickly reversed the energy substrate switch. Nutrient-sensing signaling molecules (AMPK and SIRT1 but not mTOR signaling) were highly expressed at the beginning of fasting (in the first 4 h). Serum insulin and leptin decreased with fasting initiation, and serum glucagon increased, but adiponectin and FGF21 showed no significant changes. Herein, we depicted in detail the timing of the metabolic response and adaptation of the liver to a 4-day water-only fast and subsequent refeeding in rats, which provides helpful support for the design of safe prolonged and intermittent fasting regimens.

Effects of 10-Day Complete Fasting on Physiological Homeostasis, Nutrition and Health Markers in Male Adults.

Fasting shows great potential in preventing chronic diseases and has to be surmounted under some extraordinary circumstances. This study aimed to investigate the safety, time effects of metabolic homeostasis and health indexes during prolonged fasting. Thirteen participants were recruited to conduct a 10-day complete fasting (CF) in a controlled health research building under medical supervision including 3-day Baseline (BL), 10-day CF, 4-day calorie restriction (CR) and 5-day full recovery (FR). Body healthy status was assessed by surveying pulse, blood pressure, body weight (BW), blood glucose and ketones, body composition and nutritional and biochemistry indexes at different times. BW declined about 7.28 kg (-9.8%) after 10-day CF, accompanied by increased pulse and decreased systolic blood pressure, but there were no changes to the myocardial enzymogram. Body composition analysis showed fat mass was constantly lost, but lean mass could recover after CR. The energy substrate switch from glucose to ketone occurred and formed a stable dynamic balance between 3-6 days of CF. The lipid metabolism presented increased total cholesterol, LDL-C, ApoA1 and almost no changes to TG and HDL-C. Prolonged CF did not influence liver function, but induced a slight decrease of kidney function. The interesting results came from the marked increase of lipid-soluble vitamins and a significant decrease of sodium and chlorine. Adults could well tol-erate a 10-day CF. A new metabolic homeostasis was achieved. No vitamins but NaCl supplement should be considered. These findings provide evidence to design a new fasting strategy for clinical practice.

Non-Invasive Skin Imaging Assessment of Human Stress During Head-Down Bed Rest Using a Portable Handheld Two-Photon Microscope.

Spaceflight presents a series of physiological and pathological challenges to astronauts resulting from ionizing radiation, microgravity, isolation, and other spaceflight hazards. These risks cause a series of aging-related diseases associated with increased oxidative stress and mitochondria dysfunction. The skin contains many autofluorescent substances, such as nicotinamide adenine dinucleotide phosphate (NAD(P)H), keratin, melanin, elastin, and collagen, which reflect physiological and pathological changes in vivo. In this study, we used a portable handheld two-photon microscope to conduct high-resolution in vivo skin imaging on volunteers during 15 days of head-down bed rest. The two-photon microscope, equipped with a flexible handheld scanning head, was used to measure two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) images of the left forearm, left front chest, and forehead of volunteers. Changes in TPEF, SHG, and the extended SHG-to-AF(TPEF) aging index of the dermis (SAAID) were measured. It was found that TPEF intensity increased during bed rest and was restored to normal levels after recovery. Meanwhile, SHG increased slightly during bed rest, and the skin aging index increased. Moreover, we found the skin TPEF signals of the left forearm were significantly negatively associated with the oxidative stress marker malondialdehyde (MDA) and DNA damage marker 8-hydroxy-2'-desoxyguanosine (8-OHdG) values of subjects during head-down bed rest. Meanwhile, the SHG signals were also significantly negatively correlated with MDA and 8-OHDG. A significant negative correlation between the extended SAAID of the left chest and serum antioxidant superoxide dismutase (SOD) levels was also found. These results demonstrate that skin autofluorescence signals can reflect changes in human oxidant status. This study provides evidence for in-orbit monitoring of changes in human stress using a portable handheld two-photon microscope for skin imaging.

Effects of 15-Days -6° Head-Down Bed Rest on the Attention Bias of Threatening Stimulus.

Previous researchers have found that head-down bed rest (HDBR) will affect the emotional state of individuals, and negative emotions such as anxiety are closely related to attention bias. The present study adopted the dot-probe task to evaluate the effects of 15-days of -6° HDBR on the attention bias of threatening stimulus in 17 young men, which was completed before (Pre-HDBR), during (HDBR-1, HDBR-8, HDBR-15), after (Post-HDBR) the bed rest. In addition, self-report inventories (State Anxiety Inventory, SAI; Positive Affect and Negative Affect Scale, PANAS) were conducted to record emotional changes. The results showed that the participants' negative affect scores on HDBR-8 were significantly lower than the HDBR-1 in PANAS while there was no significant difference on positive affect scores and anxiety scores in SAI. And the results showed that at the Pre-HDBR, HDBT-1, HDBR-15, Post-HDBR, the response speed to threatening stimulus was faster than neutral stimulus, but no statistical significance. However, reaction time of threatening stimulus is significantly longer than neutral stimulus in the HDBR-8, indicating that HDBR may have an effect on the participants' attention bias, and this effect is manifested as attention avoidance.

Effects of 15-Day Head-Down Bed Rest on Emotional Time Perception.

Accurate time perception is clearly essential for the successful implementation of space missions. To elucidate the effect of microgravity on time perception, we used three emotional picture stimuli: neutral, fear, and disgust, in combination with a temporal bisection task to measure 16 male participants' time perception in 15 days of -6° head-down bed rest, which is a reliable simulation model for most physiological effects of spaceflight. We found that: (1) participants showed temporal overestimation of the fear stimuli in the middle phase (day 8), suggesting that when participants' behavioral simulations were consistent with the action implications of the emotional stimuli, they could still elicit an overestimation of time even if the subjective arousal of the emotional stimuli was not high. (2) Participants' temporal sensitivity tends to get worse in the bed rest phase (days 8 and 15) and better in the post-bed rest phase, especially for neutral and fear stimuli, suggesting that multiple presentations of short-term emotional stimuli may also lead to a lack of affective effects. This reduced the pacemaker rate and affected temporal perceptual sensitivity. Also, this may be related to changes in physiological factors in participants in the bed rest state, such as reduced vagal excitability. These results provide new evidence to support the theory of embodied cognition in the context of time perception in head-down bed rest and suggest important perspectives for future perception science research in special environments such as microgravity.

Current Progression: Application of High-Throughput Sequencing Technique in Space Microbiology.

During a spaceflight, astronauts need to live in a spacecraft on orbit for a long time, and the relationship between humans and microorganisms in the closed environment of space is not the same as on the ground. The dynamic study of microorganisms in confined space shows that with the extension of the isolation time, harmful bacteria gradually accumulate. Monitoring and controlling microbial pollution in a confined environment system are very important for crew health and the sustainable operation of a space life support system. Culture-based assays have been used traditionally to assess the microbial loads in a spacecraft, and uncultured-based techniques are already under way according to the NASA global exploration roadmap. High-throughput sequencing technology has been used generally to study the communities of the environment and human on the ground and shows its broad prospects applied onboard. We here review the recent application of high-throughput sequencing on space microbiology and analyze its feasibility and potential as an on-orbit detection technology.

Temporal Characteristics of the Oropharyngeal and Nasal Microbiota Structure in Crewmembers Stayed 180 Days in the Controlled Ecological Life Support System.

Confined experiments are carried out to simulate the closed environment of space capsule on the ground. The Chinese Controlled Ecological Life Support System (CELSS) is designed including a closed-loop system supporting 4 healthy volunteers surviving for 180 days, and we aim to reveal the temporal characteristics of the oropharyngeal and nasal microbiota structure in crewmembers stayed 180 days in the CELSS, so as to accumulate the information about microbiota balance associated with respiratory health for estimating health risk in future spaceflight. We investigated the distribution of microorganisms and their dynamic characteristics in the nasal cavity and oropharynx of occupants with prolonged confinement. Based on the 16S rDNA v3-v4 regions using Illumina high-throughput sequencing technology, the oropharyngeal and nasal microbiota were monitored at eight time points during confinement. There were significant differences between oropharyngeal and nasal microbiota, and there were also individual differences among the same site of different volunteers. Analysis on the structure of the microbiota showed that, in the phylum taxon, the nasal bacteria mainly belonged to Actinobacteria, Firmicutes, Proteobacteria, Bacteroidetes, etc. In addition to the above phyla, in oropharyngeal bacteria Fusobacterial accounted for a relatively high proportion. In the genus taxon, the nasal and oropharyngeal bacteria were independent. Corynebacterium and Staphylococcus were dominant in nasal cavity, and Corynebacterium, Streptococcus, and Neisseria were dominant in oropharynx. With the extension of the confinement time, the abundance of Staphylococcus in the nasal cavity and Neisseria in the oropharynx increased, and the index Chao fluctuated greatly from 30 to 90 days after the volunteers entered the CELSS. Conclusion: The structure and diversity of the nasal and oropharyngeal microbiota changed in the CELSS, and there was the phenomenon of migration between occupants, suggesting that the microbiota structure and health of the respiratory tract could be affected by living in a closed environment for a long time.

EBP50 suppresses the proliferation of MCF-7 human breast cancer cells via promoting Beclin-1/p62-mediated lysosomal degradation of c-Myc.

c-Myc, a key activator of cell proliferation and angiogenesis, promotes the development and progression of breast cancer. Ezrin-radixin-moesin-binding phosphoprotein-50 (EBP50) is a multifunctional scaffold protein that suppresses the proliferation of breast cancer cells. In this study we investigated whether the cancer-suppressing effects of EBP50 resulted from its regulation of c-Myc signaling in human breast cancer MCF-7 cells in vitro and in vivo. We first found a significant correlation between EBP50 and c-Myc expression levels in breast cancer tissue, and demonstrated that EBP50 suppressed cell proliferation through decreasing the expression of c-Myc and its downstream proteins cyclin A, E and Cdc25A in MCF-7 cells. We further showed that EBP50 did not regulate c-Myc mRNA expression, but it promoted the degradation of c-Myc through the autophagic lysosomal pathway. Moreover, EBP50 promoted integration between c-Myc and p62, an autophagic cargo protein, triggering the autophagic lysosomal degradation of c-Myc. In EBP50-silenced MCF-7 cells, activation of autophagy by Beclin-1 promoted the degradation of c-Myc and inhibited cell proliferation. These results demonstrate that the EBP50/Beclin-1/p62/c-Myc signaling pathway plays a role in the proliferation in MCF-7 breast cancer cells: EBP50 stimulates the autophagic lysosomal degradation of c-Myc, thereby inhibits the proliferation of MCF-7 cells. Based on our results, promoting the lysosomal degradation of c-Myc might be a promising new strategy for treating breast cancer.

Inhibition of autophagy recovers cardiac dysfunction and atrophy in response to tail-suspension.

AIMS: Physical inactivity during space flight or prolonged bed rest may cause cardiac dysfunction and atrophy, but the exact mechanism that governs the regulation of myocardial dysfunction and cardiac atrophy remains poorly understood. Autophagy, a protein degradation pathway, has recently been shown to be involved in the regulation of cardiac dysfunction and atrophy. In this study, we investigated the relationships between dysfunction and inactivity-induced atrophy and autophagy in rat cardiac tissue. MAIN METHODS: Physical inactivity was simulated by a tail suspension model, and cardiac function was examined by echocardiography. Cardiac atrophy was measured by wheat germ agglutinin staining and autophagic activity was detected by Western blot analysis and immunofluorescence staining. KEY FINDINGS: We demonstrated that cardiac function, especially contractility, declined and the area of cardiac atrophy increased in the tail-suspended cardiac tissue. Additionally, the cross-sectional area of myocardial cells decreased; however, apoptosis did not increase with tail suspension. Similarly, the expression of autophagy-related proteins and the number of autophagosomes were elevated in the tail-suspended cardiac tissue. Moreover, the administration of chloroquine, an autophagy inhibitor, reversed cardiac dysfunction and atrophy via the suppression of autophagic activity during suspension. Our results indicate that autophagy facilitates the development and progression of cardiac dysfunction and atrophy induced by tail suspension. SIGNIFICANCE: Our studies hint that the components of the autophagy-related signaling pathway are potential therapeutic targets for the treatment of cardiac diseases induced by physical inactivity.

Activation of Toll-like receptor 9 attenuates unilateral ureteral obstruction-induced renal fibrosis.

AIM: to study whether activation of TLR9 by CpG-ODN would protect against and/or reverse renal fibrosis. METHODS: animals were treated with CpG-ODN before or after undergoing a unilateral ureteral obstruction (UUO) procedure. The interstitial fibrotic lesions of obstructed kidneys were evaluated using histology and immunohistostaining. The Th2-type cytokine profile and the expression and activity of sma and mad related protein (Smad)3, signal transducers and activators of transcription (Stat)3, extracellular regulated protein kinases (ERK), and p38 kinase were determined using RT-PCR or Western blot. RESULTS: the obstructed kidneys displayed a significant increase in interstitial fibrosis, an infiltration of macrophages in the interstitium, and an enhanced expression of Th2 cytokines. Prophylactic application of CpG-ODN (40 microg/kg every 3 days from 2 h before UUO until the 14th day after UUO) suppressed the expression of α-smooth muscle actin, collagen deposition, and hydroxyproline in the UUO kidneys of rats. Moreover, CpG-ODN not only decreased the infiltration of macrophages but also inhibited the expression of chemokines CCL2 and CCL5, the Th2 cytokine IL-13, and the profibrogenic cytokines transforming growth factor (TGF)-ß1 and plasminogen activator inhibitor (PAI)-1 in UUO kidneys of rats. Importantly, therapeutic administration of CpG-ODN (10 microg/mouse, ip, every 3 days from the 4th day to 21st day after UUO) reversed the established renal fibrosis, which was accompanied by significant reductions in the activity of ERK, Smad3, and Stat3 and an increase in the activity of p38 kinase. CONCLUSION: the activation of TLR9 by CpG-ODN attenuates UUO-induced renal fibrosis by reversing an immunosuppressive microenvironment in the fibrotic renal tissue, which might be a novel therapeutic strategy against fibrotic renal diseases.

Intracellular or extracellular heat shock protein 70 differentially regulates cardiac remodelling in pressure overload mice.

AIMS: Innate and adaptive immune responses are associated with the development of hypertension-induced myocardial hypertrophy and fibrosis. As a result, we investigated whether heat shock protein (HSP) 70, which is a molecule of damage-associated molecular patterns, could induce inflammation in the myocardium and promote the development of hypertension-induced cardiac hypertrophy and fibrosis. METHODS AND RESULTS: We found that HSP70 serum levels, as well as the amount of HSP70 translocation to the cardiomyocyte membranes and the interstitial space, were elevated in the hypertensive mice caused by abdominal aortic constriction (AAC). Transcriptional inhibition of HSP70 expression by a specific heat shock transcript factor inhibitor, KNK437, reduced the serum level, and the re-distribution of HSP70. It promoted myocardial hypertrophy and cardiac dysfunctions although it protected animals from AAC-induced cardiac fibrosis. On the other hand, the functional antagonism of HSP70 by an anti-HSP70 antibody attenuated AAC-induced cardiac hypertrophy and fibrosis without adverse haemodynamic effects. The cardioprotective effect of the anti-HSP70 antibody was largely attributed to its ability to block AAC-activated immune response in the heart, as was indicated by suppressing the hypertension-enhanced conjugation of HSP70 with toll-like receptor 4, reducing heart-infiltrating macrophages, decreasing the expression of pro-inflammatory factor monocyte chemoattractant protein-1 and profibrotic factor transforming growth factor beta 1, and attenuating pro-hypertrophy signal MAPK P38 and ERK. CONCLUSION: These results indicate that intracellular and extracellular HSP70 have different roles in the regulation of cardiac remodelling and function in response to hypertension. Extracellular HSP70 is a potential therapeutic target against cardiac hypertrophy and fibrosis.

Blocking TLR2 activity attenuates pulmonary metastases of tumor.

BACKGROUND: Metastasis is the most pivotal cause of mortality in cancer patients. Immune tolerance plays a crucial role in tumor progression and metastasis. METHODS AND FINDINGS: In this study, we investigated the potential roles and mechanisms of TLR2 signaling on tumor metastasis in a mouse model of intravenously injected B16 melanoma cells. Multiple subtypes of TLRs were expressed on B16 cells and several human cancer cell lines; TLR2 mediated the invasive activity of these cells. High metastatic B16 cells released more heat shock protein 60 than poor metastatic B16-F1 cells. Importantly, heat shock protein 60 released by tumor cells caused a persistent activation of TLR2 and was critical in the constitutive activation of transcription factor Stat3, leading to the release of immunosuppressive cytokines and chemokines. Moreover, targeting TLR2 markedly reduced pulmonary metastases and increased the survival of B16-bearing mice by reversing B16 cells induced immunosuppressive microenvironment and restoring tumor-killing cells such as CD8(+) T cells and M1 macrophages. Combining an anti-TLR2 antibody and a cytotoxic agent, gemcitabine, provided a further improvement in the survival of tumor-bearing mice. CONCLUSIONS AND SIGNIFICANCE: Our results demonstrate that TLR2 is an attractive target against metastasis and that targeting immunosuppressive microenvironment using anti-TLR2 antibody is a novel therapeutic strategy for combating a life-threatening metastasis.

Bacillus Calmette-Guérin and TLR4 agonist prevent cardiovascular hypertrophy and fibrosis by regulating immune microenvironment.

Hypertension-induced cardiovascular hypertrophy and fibrosis are critical in the development of heart failure. The activity of TLRs has been found to be involved in the development of pressure overload-induced myocardial hypertrophy and cardiac fibrosis. We wondered whether vaccine bacillus Calmette-Guérin (BCG), which activated TLR4 to elicit immune responses, modulated the pressure overload-stimulated cardiovascular hypertrophy and cardiac fibrosis in the murine models of abdominal aortic constriction (AAC)-induced hypertension. Before or after AAC, animals received BCG, TLR4 agonist, IFN-gamma, or TLR4 antagonist i.p. BCG and TLR4 agonist significantly prevented AAC-induced cardiovascular hypertrophy and reactive cardiac fibrosis with no changes in hemodynamics. Moreover, TLR4 antagonist reversed the BCG- and TLR4 agonist-induced actions of anti-cardiovascular hypertrophy and cardiac fibrosis. BCG decreased the expression of TLR2 or TLR4 on the heart tissue but TLR4 agonist increased the expression of TLR2 or TLR4 on the immune cells that infiltrate into the heart tissue. This led to an increased expression ratio of IFN-gamma/TGF-beta in the heart. The cardiac protective effects of BCG and TLR4 agonist are related to their regulation of ERK-Akt and p38-NF-kappaB signal pathways in the heart. In conclusion, the activity of TLR4 plays a critical role in the mediation of pressure overload-induced myocardial hypertrophy and fibrosis. The regulation of immune responses by BCG and TLR4 agonist has a great potential for the prevention and treatment of hypertension-induced myocardial hypertrophy and cardiac fibrosis.

[Establishment of an IR-HIRc cell model for screening GFAT inhibitor].

AIM: To set up an IR-HIRc cell model for screening the inhibitor of GFAT (glutamine: fructose-6-phosphate amidotransferase) , the key enzyme in the hexosamine biosynthesis pathway (HBP). METHODS: For GFAT activity assay, the GDH method was improved by adjusting the value of pH in the reaction system and the concentrations of the reactants. The sensitivity to insulin in the cells was estimated by the measurement of insulin-induced glucose-uptake. The IR-HIRc model was set up by the stimulation of long-action insulin for 36 h. The IR-HIRc model and GDH method was used for screening GFAT inhibitor. RESULTS: With the administration of 25 nmol x L(-1) long-action insulin in HIRe cells for 36 hours, the GFAT activity increased by 47% and the insulin-induced glucose-uptake decreased by 21%. Azaserine, a GFAT inhibitor, inhibited GFAT activity significantly in a dose-dependent manner in IR-HIRc model. CONCLUSION: With the stimulation of 25 nmol x L(-1) long-action insulin for 36 h, excess hexosamine flux and insulin resistant in IR-HIRc cell model was set up, which can be used for screening

Effects of L.F04, the active fraction of Lycopus lucidus, on erythrocytes rheological property.

OBJECTIVE: To study the effects of L.F04, the active fraction of Lycopus lucidus, on erythrocytes rheological property so as to investigate its mechanism in promoting blood circulation and removing blood stasis. METHOD: The effects of L.F04 (used for treatment for 10 days in different dosages) on deformability, aggregation and membrane liquidity of erythrocytes (MLE) as well as whole blood apparent viscosity (eta(b)) were examined on the basis of rat model of blood-stasis syndrome induced by venous injection of high molecular weight dextran. RESULT: As compared with the normal control group, the model group's RBC deformability and MLE were lower, and the aggregation of erythrocytes and eta(b) were higher. Compared with the model group, both L.F04 0.612 g/kg and 0.306 g/kg showed significant effect in improving deformability and inhibiting aggregation of red blood cells (RBC) and reducing blood viscosity. The trend of improving MLE was also shown. CONCLUSION: L.F04 could significantly improve the abnormal rheological property of erythrocytes.

[Effects of Chinese herb compound on myocardial SDH, ATP-ase and energy reserves in tail-suspended rats].

OBJECTIVE: To investigate effects of Chinese herb compound on myocardial SDH, ATP-ase and energy reserves in tail-suspended rats. METHOD: Male SD rats were randomly divided into three groups (n=10 each): (A) normal control group; (B) tail-suspended group; (C) tail-suspended + Chinese Medical herb compound group. Rats in group B and C were tail-suspended (-30 degrees) for 5 d to simulate weightlessness. All rats B were decapitated after the experiment. Myocardial SDH (method of Anderson N-BT), ATP-ase (method of Wachstein and Meisel) and energy reserves (method of HPLC) were examined. RESULT: Compared with rats in groups A and C, SDH activity increased, SDH staining deepened, value of OD SDH enhanced, ATP-ase activity and OD value increased and enhanced significantly (P<0.01) but value of myocardial energy reserves decreased in group B rats. CONCLUSION: Tail-suspension strengthens compensatory oxidation metabolism of cardiac muscle and activates SDH and ATP-ase, at the same time decrease, myocardial energy reserves. Normal are maintained the low level of metabolism by the medical herb compound used which shows a protecting effects through mitigation, tranguilization and replenishment of Qi.

[Preliminary (correction of Priliminary) study on effects of "planning treatment according to diagnosis" on physiological changes during simulated weightlessness].

OBJECTIVE: To observe effects of the planning treatment according to diagnosis on body syndromes caused by simulated weightlessness. METHOD: Ten subjects underwent HDT -6 degrees for 14 d were randomly divided into the traditional Chinese Medicine group (ME) and control group (CON). Differentiation of syndromes were made and parameters related to the differentiation syndromes, including plasma cortisone, blood viscosity, red cell deformation, excretion rate of urine xylose, and amount of urine were surveyed simultaneously. RESULT: Both differentiation of syndromes and the physiological parameters in group ME could be maintained at the pre-bed rest levels or changed only slightly. CONCLUSION: The Chinese herb compound had an adjusting effect on deficiency of kidney-Yin, blood stasis, insufficiency of spleen-Qi and changes of related physiological parameters caused by 14 d bed rest simulated weightlessness, among which the effect on deficiency of kidney-yin and blood stasis were more distinct.