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Introduction: Long‐term spaceflight composite stress (LSCS) can cause adverse effects on human systems, including the central nervous system, which could trigger anxiety and depression. Aims: This study aimed to identify changes in hippocampus synaptic plasticity under LSCS. Methods: The present study simulated the real long‐term space station environment by conducting a 42‐day experiment that involved simulating microgravity, isolation, noise, circadian rhythm disruptions, and low pressure. The mood and behavior of the rats were assessed by behavior test. Transmission electron microscopy and patch‐clamp were used to detect the changes in synapse morphology and electrophysiology, and finally, the expression of NMDA receptor channel proteins was detected by western blotting. Results: The results showed that significant weight loss, anxiety, and depressive behaviors in rats were observed after being exposed to LSCS environment for 42 days. The synaptic structure was severely damaged, manifested as an obvious decrease in postsynaptic density thickness and synaptic interface curvature (p < 0.05; p < 0.05, respectively). Meanwhile, LTP was significantly impaired (p < 0.0001), and currents in the NMDAR channel were also significantly reduced (p < 0.0001). Further analysis found that LSCS decreased the expression of two key subtype proteins on this channel. Conclusion: These results suggested that LSCS‐induced depressive behaviors by impairing synaptic plasticity in rat hippocampus. [ABSTRACT FROM AUTHOR]

The article presents the findings of an experimental work and research on the effects of L. F04, the active fraction of the herb Lycopus lucidus, on erythrocytes rheological property, conducted by Shi Hong-zhi, Li Yong-zhi et al. Lycopus lucidus has effects in resisting coagulation and thrombosis. Cell rheology detector type LG-B-190 manufactured by Shidi Scientific Instrument Co. is one of the instruments used in the study. After being injected with dextran 500, rats in the model group showed characteristics of blood stasis.

Objective: To investigate effects of Chinese herb-compound on blood rheology and circulatory system of rabbits under simulated weightlessness in order to provide bases for protecting against the influence of simulated weightlessness on cardiovascular function., Method: Rabbits were exposed to head-down tilt (HDT -20 degrees) for 9 d to simulate weightlessness. The effect of Chinese herb-compound on indices related to blood rheology, blood-fat and orthostatic tolerance in these rabbits were examined., Result: After head-down tilt, hematocrit value and red blood cells deformability decreased significantly; cholesterol and low density lipoprotein increased markedly; plasma fibrinogen content and triglyceride showed increasing trend. Administration of the Chinese herb-compound didn't improve the blood rheology indices, but showed a trend to decrease triglyceride and to inhibit the increase of cholesterol. In the head-up tilt (HUT) plus lower body negative pressure (LBNP) experiment, orthostatic tolerance time of the rabbits in the control group decreased, and myocardial ischemic changes in ECG, such as dropped ST segment, inverse T wave, and arrhythmia were observed. While in the Chinese herb-compound group, the heart rate of the rabbits kept smooth, ischemic changes in ECG were not clear, and orthostatic tolerance time increased., Conclusion: The Chinese herb-compound shows an effect of preventing orthostatic tolerance from decreasing, and improves blood-fat metabolism. It regulates different human systems on the whole, and increases ability of adaptation to ill environment.

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.

Objective: To study the effect of active fractions from Lycopus lucidus (L. F04) on platelet aggregation and thrombus formation so as to investigate its mechanism of promoting blood circulation and removing blood stasis., Method: The effects of Lycopus lucidus L. F04 on platelet aggregation induced by ADP in vivo, and thrombosis of artery-vein by-pass and thrombus formed in circuitous loop in vitro were examined using the blood stasis animal model of rats made by injecting high molecular weight dextran (HMWD)., Result: The increase of maximum platelet aggregation rate induced by ADP in vivo in HMWD model was evidently inhibited with 0.408 g/kg or 0.204 g/kg or L. F04, and the effect showed a trend of concentration-dependence. As compared with the control, the thrombus weight in rat model of blood stasis increased clearly and its length showed only a trend of increase. Both 0.408 g/kg and 0.204 g/kg of L. F04 had the effect of resisting the thrombus formation, while 0.408 g/kg showed better effects of reducing the thrombus dry weight and wet weight. Both 0.408 g/kg and 0.204 g/kg of L. F04 could inhibit the thrombosis in artery-vein by-pass; the inhibition rates were 27.41% and 27.14% respectively., Conclusion: Lycopus lucidus L. F04 could significantly inhibit platelet aggregation and thrombus formation.

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.

Objective: To investigate effects of Qiang Gu Kang Wei prescription on bone morphology in tail-suspended rats., Method: Rats were tail-suspended (-30 degrees) for 21 d to simulate weightlessness. The effects of this prescription on thickness of periost and cortex at epiphyseal plate of tibial shaft and 3 mm under it were examined. The effects of this prescription on histology and ultrastructure of tibia were also observed., Result: Compared with the normal control, cortex at both epiphyseal plate of tibial shaft and 3 mm under it in suspended rats thinned significantly (P<0.01 or P<0.05). Histological observation showed that in bone of suspended rats, uncalcific matrix was more, bone cells' number was lower and their appearance was more infantile, osteoblasts were less and smaller, while osteoclasts were more and larger, haversian system of transection also showed more irregular than in bone of normal control. Ultrastructure observation showed that the function of osteoblasts was inhabited and that of osteoclasts was active. All the three doses groups of the prescription could increase cortex at either epiphyseal plate of tibial shaft or 3 mm under it (P<0.01 or P<0.05) compared with the tail-suspended group. The appearance of bone in the three groups was improved as well under optical or electron microscope., Conclusion: This prescription could improve abnormal change in bone morphology resulted from being tail-suspended in rats and make it normal.

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.

Objective: To investigate the effect of "Qiang Gu Kang Wei" prescription on bone metabolism in simulated weightless rats., Method: Male SD rats were randomly divided into five groups: 1) free active control (FAC); 2) tail-suspended control (TS); 3) tail-suspended and treated with large dose of the prescription (TS + L) (30 g/kg); 4) tail-suspended and treated with middle dose of the prescription (TS + M) (20 g/kg); 5) tail suspended and treated with small dose of the prescription (TS + S) (10 g/kg). The experiment lasted 3 weeks. The effect of the prescription on bone biomechanical properties, bone density, bone mineral contents, and bone biochemical markers of bone metabolism were examined., Result: Bone biomechanical properties, bone density, total and bound bone gla protein (BGP) of serum all increased significantly in three groups treated with the prescription., Conclusion: "Qiang Gu Kang Wei" prescription prevents bone loss, hence maintains bone density and bone biomechanical properties under simulated weightlessness.

Objective: To investigate effects of "Qiang Gu Kang Wei" prescription on biochemical indices of bone and related organs in tail-suspended rats., Method: Rats were tail-suspended (-30 degrees) for 21 d to simulate weightlessness. The effect of this prescription on biochemical indices such as Ca, P in serum, osteocalcin (BGP) in serum and bone, oxyproline hydroxyproline (Hyp) in bone, alkaliphosphatase (ALP) in serum, small intestine and bone in these rats were examined., Result: Comparing with the normal control, serum Ca decreased significantly (P<0.05) while serum P showed only a trend to decrease, at the same time BGP dropped in both serum and bone (P<0.05) and Hyp dropped only in bone (P<0.05). There was significant decrease of ALP activity in serum, small intestine and bone (P<0.01 or P<0.05) in suspended rats. The prescription showed different effects with different doses. In all the three dose groups (30 g/kg, 20 g/kg, 10 g/kg) Ca and P in serum levels increased (P<0.01 or P<0.05), BGP in serum and bone improved (P<0.05) or showed only a trend to increase. ALP activity increased in serum, small intestine and bone (P<0.05). Increase of Hyp in bone was found in the middle and the small dose groups (P<0.05)., Conclusion: This prescription shows an effect of improving biochemical indices in bone and related organs such as serum and small intestine in tail-suspended rats. But no distinct concentration-dependence was found.

Objective. To study the effects of active fractions from Lycopus lucidus (L. F04) on erythrocyte rheology so as to investigate its mechanism of promoting blood circulation and removing blood stasis. Method. The effects of L. F04 on erythrocytes deformability, aggregation, liquidity of membrane were examined in the present study and the blood stasis animal model of rats made by injecting high molecular weight dextran (HMWD) was used. Result. HMWD injection decreased red blood cells deformability (P<0.05) and liquidity of membrane (P<0.01) and increased erythrocytes aggregation (P<005). Compared with the model, both L. F04 0.612 g/kg and 0.306 g/kg improved red blood cells deformability (P<0.05), inhibited erythrocytes aggregation (P<0.05), and showed the trend of improving liquidity of membrane. But there was no concentration-dependence. Conclusion. L. F04 can significantly improve the deviant erythrocyte rheology characteristics.

Objective. To investigate the effects of Qiang Gu Kang Wei compound on hemorheology in tail-suspended rats. Method. Rats were tail-suspended (-30 degrees) for 21 d to simulate weightlessness. The effect of the compound on erythrocyte sedimentation rate (ESR), hematocrit value (HCT), plasma fibrinogen content (PFC), blood viscosity, red blood cells deformability and erythrocytes aggregation were examined. Result. PFC, whole blood reducing viscosity (eta h), whole blood viscosity (eta b), erythrocyte rigid index (IR) and maximum aggregation index (MAXD) increased significantly (P<0.01 or P<0.05 ) and maximum deformity index (DImax) (P<0.01) decreased significantly in suspended rats as compared with the normal control. Different doses of the compound showed different effects. The small dose group (10 g/kg) inhabited eta h and eta b (P<0.01 or P<0.05) of all shear rates, abnormal IR and MAXD (P<0.01); The middle dose group (20 g/kg) decreased PFC (P<0.01); The big dose group (30 g/kg) inhabited eta h and eta b (P<0.01 or P<0.05) of high shear rates, decreased IR (P<0.01), and improved DImax (P<0.01). Conclusion. This compound could improve hemorheology in tail-suspended rats. But there was no concentration-dependence.