Exploring miR-21 as a key regulator in two distinct approaches of bone marrow stromal cells differentiation into Schwann-like cells.

The differentiation of bone marrow stromal cells (BMSCs) into Schwann-like cells (SCLCs) has the potential to promote the structural and functional restoration of injured axons. However, the optimal induction protocol and its underlying mechanisms remain unclear. This study aimed to compare the effectiveness of different induction protocols in promoting the differentiation of rat BMSCs into SCLCs and to explore their potential mechanisms. BMSCs were induced using two distinct methods: a composite factor induction approach (Protocol-1) and a conditioned culture medium induction approach (Protocol-2). The expression of Schwann cells (SCs) marker proteins and neurotrophic factors (NTFs) in the differentiated cells was assessed. Cell proliferation and apoptosis were also measured. During induction, changes in miR-21 and Sprouty RTK signaling antagonist 2 (SPRY2) mRNA were analyzed. Following the transfection of BMSCs with miR-21 agomir or miR-21 antagomir, induction was carried out using both protocols, and the expression of SPRY2, ERK1/2, and SCs marker proteins was examined. The results revealed that NTFs expression was higher in Protocol-1, whereas SCs marker proteins expression did not significantly differ between the two groups. Compared to Protocol-1, Protocol-2 exhibited enhanced cell proliferation and fewer apoptotic and necrotic cells. Both protocols showed a negative correlation between miR-21 and SPRY2 expression throughout the induction stages. After induction, the miR-21 agomir group exhibited reduced SPRY2 expression, increased ERK1/2 expression, and significantly elevated expression of SCs marker proteins. This study demonstrates that Protocol-1 yields higher NTFs expression, whereas Protocol-2 results in stronger SCLCs proliferation. Upregulating miR-21 suppresses SPRY2 expression, activates the ERK1/2 signaling pathway, and promotes BMSC differentiation into SCLCs.

Thoracic perivascular adipose tissue inhibits VSMC apoptosis and aortic aneurysm formation in mice via the secretome of browning adipocytes.

Abdominal aortic aneurysm (AAA) is a dangerous vascular disease without any effective drug therapies so far. Emerging evidence suggests the phenotypic differences in perivascular adipose tissue (PVAT) between regions of the aorta are implicated in the development of atherosclerosis evidenced by the abdominal aorta more vulnerable to atherosclerosis than the thoracic aorta in large animals and humans. The prevalence of thoracic aortic aneurysms (TAA) is much less than that of abdominal aortic aneurysms (AAA). In this study we investigated the effect of thoracic PVAT (T-PVAT) transplantation on aortic aneurysm formation and the impact of T-PVAT on vascular smooth muscle cells. Calcium phosphate-induced mouse AAA model was established. T-PVAT (20 mg) was implanted around the abdominal aorta of recipient mice after removal of endogenous abdominal PVAT (A-PVAT) and calcium phosphate treatment. Mice were sacrificed two weeks after the surgery and the maximum external diameter of infrarenal aorta was measured. We found that T-PVAT displayed a more BAT-like phenotype than A-PVAT; transplantation of T-PVAT significantly attenuated calcium phosphate-induced abdominal aortic dilation and elastic degradation as compared to sham control or A-PVAT transplantation. In addition, T-PVAT transplantation largely preserved smooth muscle cell content in the abdominal aortic wall. Co-culture of T-PVAT with vascular smooth muscle cells (VSMCs) significantly inhibited H2O2- or TNFα plus cycloheximide-induced VSMC apoptosis. RNA sequencing analysis showed that T-PVAT was enriched by browning adipocytes and anti-apoptotic secretory proteins. We further verified that the secretome of mature adipocytes isolated from T-PVAT significantly inhibited H2O2- or TNFα plus cycloheximide-induced VSMC apoptosis. Using proteomic and bioinformatic analyses we identified cartilage oligomeric matrix protein (COMP) as a secreted protein significantly increased in T-PVAT. Recombinant COMP protein significantly inhibited VSMC apoptosis. We conclude that T-PVAT exerts anti-apoptosis effect on VSMCs and attenuates AAA formation, which is possibly attributed to the secretome of browning adipocytes.

Asymmetric Cyanosilylation of Aldehydes by a Lewis Acid/Base Synergistic Catalyst of Chiral Metal Clusters.

Metal clusters with well-defined crystal structures are extremely useful for studying the synergistic catalytic effects and associated catalytic mechanisms. In this study, two pairs of chiral lanthanide-transition metal clusters (R)/(S)-Co3Ln2 (Ln = Tb or Dy) were synthesized using Schiff-base ligands [(R)- or (S)-H3L] with multiple Lewis base sites (O sites). The as-prepared (R)/(S)-Co3Ln2 chiral metal clusters exhibited good catalytic functionality in the asymmetric synthesis of chiral cyanohydrins, with high conversions of up to 99% and medium-to-high enantiomeric excess values of up to 78%. The catalysis process followed a mechanism in which the bifunctional metal clusters of (R)/(S)-Co3Ln2, containing Lewis acid sites and Lewis base sites, simultaneously activated the aldehydes and trimethylsilyl cyanide, respectively. Consequently, synergistic catalysis was realized. The enantioselectivity of the different aldehydes and stereochemical configuration of the resulting products are attributed to the formation of a steric chiral pocket via the external chiral ligands on the clusters. In addition, heterogeneous asymmetric cyanosilylation using (R)/(S)-Co3Ln2 chiral metal clusters achieved high chemoselectivity and regioselectivity under mild conditions.

Hierarchical Assembly of Coordination Macromolecules with Atypical Geometries: Gd44 Co28 Crown and Gd95 Co60 Cage.

The discovered giant clusters are always highly symmetric owing to the spontaneous assembly of one or two basic units. Herein we report the Gd44 Co28 crown and Gd95 Co60 cage, formulated as [Gd44 Co28 (IDA)20 (OH)72 (CO3 )12 (OAc)28 (H2 O)64 ]⋅(ClO4 )24 and [Na4 Gd95 Co60 (IDA)40 (OH)150 (CO3 )40 (OAc)58 (H2 O)164 ] ⋅ (ClO4 )41 (H2 IDA=iminodiacetic acid), respectively, by providing a library containing multiple low-nuclearity units. The heart-like units and crown-like tetramer found in both compounds indicate unprecedented assembly levels, leading to an atypical geometry characteristic compared to the giant clusters directly assembled by regular units. These two clusters not only significantly increase the size of Ln-Co clusters but also exhibit the enhanced magnetic entropy change at ultra-low temperatures. This work provided an effective way to fabricate cluster compounds with giant size and geometry complexity simultaneously.

Combination of BMSCs-laden acellular nerve xenografts transplantation and G-CSF administration promotes sciatic nerve regeneration.

Peripheral nerve gaps often lead to interrupted innervation, manifesting as severe sensory and motor dysfunctions. The repairs of the nerve injuries have not achieved satisfactory curative effects in clinic. The transplantation of bone marrow stromal cells (BMSCs)-laden acellular nerve xenografts (ANX) has been proven more effective than the acellular nerve allografting. Besides, granulocyte colony-stimulating factor (G-CSF) can inhibit inflammation and apoptosis, and thus is conducive to the microenvironmental improvement of axonal regeneration. This study aims to investigate the joint effect of BMSCs-seeded ANX grafting and G-CSF administration, and explore the relevant mechanisms. Adult SD rats were divided into five groups randomly: ANX group, ANX combined with G-CSF group, BMSCs-laden ANX group, BMSCs-laden ANX combined with G-CSF group, and autograft group. Eight weeks after transplantation, the detection of praxiology and neuroelectrophysiology was conducted, and then the morphology of the regenerated nerves was analyzed. The inflammatory response and apoptosis in the nerve grafts as well as the expression of the growth-promoting factors in the regenerated tissues were further assayed. G-CSF intervention and BMSCs implanting synergistically promoted peripheral nerve regeneration and functional recovery following ANX bridging, and the restoration effect was matchable with that of the autologous nerve grafting. Moreover, local inflammation was alleviated, the apoptosis of the seeded BMSCs was decreased, and the levels of the neuromodulatory factors were elevated. In conclusion, the union application of BMSCs-implanted ANX and G-CSF ameliorated the niche of neurotization and advanced nerve regeneration substantially. The strategy achieved the favorable effectiveness as an alternative to the autotransplantation.

Synergistic effects of G-CSF and bone marrow stromal cells on nerve regeneration with acellular nerve xenografts.

Peripheral nerve defects result in severe denervation presenting sensory and motor functional incapacitation. Currently, a satisfactory therapeutic treatment promoting the repair of injured nerves is not available. As shown in our previous study, acellular nerve xenografts (ANX) implanted with bone marrow stromal cells (BMSCs) replaced allografts and promoted nerve regeneration. Additionally, granulocyte-colony stimulating factor (G-CSF) has been proven to mobilize supplemental cells and enhance vascularization in the niche. Thus, the study aimed to explore whether the combination of G-CSF and BMSC-laden ANX exhibited a synergistic effect. Adult Sprague-Dawley (SD) rats were randomly divided into five groups: ANX group, ANX combined with G-CSF group, BMSCs-laden ANX group, BMSCs-laden ANX combined with G-CSF group and autograft group. Electrophysiological parameters and weight ratios of tibialis anterior muscles were detected at 8 weeks post-transplantation. The morphology of the regenerated nerves was assayed, and growth-promoting factors present in the nerve grafts following G-CSF administration or BMSCs seeding were also investigated. Nerve regeneration and functional rehabilitation induced by the combination therapy were significantly advanced, and the rehabilitation efficacy was comparable with autografting. Moreover, the expression of Schwann cell markers, neurotrophic factors and neovessel markers in the nerve grafts was substantially increased. In conclusion, G-CSF administration and BMSCs transplantation synergistically promoted the regeneration of ANX-bridged nerves, which offers a superior strategy to replace autografts in repairing peripheral nerve injuries.

[Analyses of exercise-induced muscle damage-specific microRNA expression and molecular target of sarcolemmal damage in rats].

In the present study, we were to screen the specific microRNA (miRNA) of exercise-induced muscle damage (EIMD) and assess the EIMD-specific miRNAs-regulated target of sarcolemmal damage in rats. Twenty-four male Sprague-Dawley (SD) rats were randomly divided into 3 groups, which included sedentary (C), 24 h post-exercise (E24) and 48 h post-exercise (E48) groups. Rat EIMD model was established by an acute eccentric exercise, i.e., a downhill running treatment at -16º gradient. EIMD characteristics were verified by Evans blue dye staining, differentially expressed miRNAs were detected by microarray assay, EIMD-specific miRNAs expressions were further validated by real-time quantitative RT-PCR (RT-qPCR), and targets of the miRNAs were predicted based on mRNA expressions of associated proteins and related pathway core molecules of sarcolemmal damage. Two EIMD-specific expressed miRNAs, including miR-206-3p and miR-139-3p, were found in the study. There was a significantly negative correlation (P < 0.05) between miR-206-3p expression and dystrophin (r = -0.68), utrophin (r = -0.64), JNK (r = -0.62) or ERK1 (r = -0.68) respectively, but no correlation was found between miR-139-3p and these biomolecules. The results suggest that: i) the expression profile of miRNAs in rat is significantly affected by EIMD, ii) miR-206-3p and miR-139-3p are the EIMD-specific miRNAs, and iii) miR-206-3p may control sarcolemmal damage by regulating dystrophin, utrophin, JNK and ERK1.

[Surface Enhanced Raman Spectroscopy Study of D-Carnitine on a New Base].

A fast and efficient way to synthesize a large number of silver nanowires was developed in this paper, in which the reaction conditions were optimized. Under the protection of Cu(NO3)2 silver nitrate was reduced by polyol with polyvinyl pyrrolidone (PVP) in existence. The silver nanowires with uniform structure and good dispersion were obtained. Surface enhancement activity of the silver nanowires was detected by using RhB as a probe molecule，its surface enhancement factor can reach 6.4×105. The results showed that the nanowires significantly enhance the Raman spectroscopy of RhB. The normal Raman spectroscopy (NRS), Raman spectroscopy of D-carnitine solution and Surface enhanced Raman Spectroscopy of D-carnitine by means of the new base were obtained. There are obvious Raman peaks at 3 100～2 800 and 1 700～200 cm-1, and the peak of 1 700～200 cm-1 in the surface enhanced Raman spectra of the D-carnitine can be obviously enhanced. The analysis showed that the angle between the molecular and silver nanoparticles were 180°. The vibrational peaks were assigned comprehensively. Compared with the NRS and SERS of D-carnitine, the detailed structural information of D-carnitine was obtained. In this paper, the surface enhanced Raman spectra of the D-carnitine absorbed on the synthesized silver nanoparticles were obtained, and the minimum detection concentration was 10-6 mol·L-1. The new method can be a rapid and characteristic way to detect D-carnitine, and it will also provide an important guidance for the studies on pharmacology of D-carnitine.

[Relationship between calcium overload and myocardial ischemia reperfusion injury and intervention strategy of Chinese herbal medicine].

The recent report from National Cardiovascular Center shows that cardiovascular diseases account for more than 40% of disease deaths among residents, so it has become the first cause of death among the residents in our country, and the mortality of coronary heart disease is increasing year by year. Revascularization can quickly open the clogged blood vessels and restore coronary blood supply, so it is an important approach for the treatment of coronary heart disease. However, the revascularization can not terminate the pathological development of coronary heart disease because it is just a local treatment method. In addition, a series of reperfusion injuries after revascularization would seriously restrict its treatment effect for coronary heart disease. Myocardial ischemia reperfusion injury is a complex pathological process, which is closely related to oxygen free radicals, calcium overload and energy metabolism disorder. The calcium overload can be seen during reperfusion in the myocardial cells, and it can cause further damages to the myocardial cells through various mechanisms. Calcium overload is a common pathway of myocardial necrosis and apoptosis, so prevention and treatment of calcium overload is an important method to prevent ischemia reperfusion. The commonly used calcium channel blockers for preventing calcium overload has made great progress, all of which can act on L-type calcium channel of vascular smooth muscle to inhibit calcium overload. However, their clinical application was restrained to a certain extent due to the single target and great side effects. Traditional Chinese medicine (TCM) is a great treasure, and many drugs in TCM have similar effects with calcium antagonists, so the development and application of such drugs would be an important task for contemporary TCM doctors to make up for the deficiency of Western medicine.

[IR and Raman spectra studies of Rotundine based on DFT].

Infrared spectroscopy (IR), the normal Raman spectroscopy (NRS) and the surface enhanced Raman spectroscopy (SERS) in new Ag/Cu nanomaterial of Rotundine were studied in the present paper. The IR and the NRS of Rotundine were calculated by the density functional theory (DFT) using B3LYP/6-311+G(d, p), then the spectral intensity graph of Rotundine were given. The vibrational peaks were assigned comprehensively by the visualization software of Gauss view 5. 0. Rotundine has obvious infrared and Raman vibrational peak in the wave number range of 3 300-2500 and 1 800-600 cm(-1). SnCl2 and PVP was used as capping agent for the silver nanoparticles in SERS of Rotundine. Finally, by using the method of cyclic immersion well dispersed silver nanoparticles was obtained and achieved good enhancement effect. This molecule acquired strong selective enhancement vibration peak, In the wave number ranges of 1 500-1 400 and 1 000-700 cm(-1) the enhancement effect is most obvious. After analyzed, the methylene of this molecule is adsorbed on the silver nanoparticles surface and the angle between the benzene ring and the silver substrate is close to 90 degrees. The theoretically calculated spectra of Rotundine are consistent with the obtained experimental spectra. There are some differences may be due to the interaction forces between molecules and so on. The visualization software displayed the structure characteristics and molecular group vibration of this molecular visually and provided important basis for assigning the vibrational peaks. Rotundine is an important traditional Chinese medicine agent contained in many kinds of sedative drugs. The study provides a strong basis for the rapid, feature and trace identification of Rotundine and also supplies important reference for the biological role of central inhibition of analgesic drugs.

Hemostasis Using Prothrombin Complex Concentrate in Patients Undergoing Cardiac Surgery: Systematic Review with Meta-Analysis.

OBJECTIVE: The purpose of present study was to comprehensívely explore the efficacy and safety of prothrombín complex concentrate (PCC) to treat massíve bleedíng in patíents undergoing cardiac surgery. METHODS: PubMed®, Embase, and Cochrane Líbrary databases were searched for studíes ínvestigating PCC administratíon duríng cardiac surgery published before September 10, 2022. Mean dífference (MD) wíth 95% confidence interval (CI) was applíed to analyze continuous data, and dichotomous data were analyzed as risk ratio (RR) with 95% CI. RESULTS: Twelve studies were included in the meta-analysis. Compared with other non-PCC treatment regimens, PCC was not assocíated with elevated mortality (RR=1.18, 95% CI=0.86-1.60, P=0.30, I2=0%), shorter hospital stay (MD=-2.17 days; 95% CI=-5.62-1.28, P=0.22, I2=91%), reduced total thoracic drainage (MD=-67.94 ml, 95% CI=-239.52-103.65, P=0.44, I2=91%), thromboembolíc events (RR=1.10, 95% CI=0.74-1.65, P=0.63, I2=39%), increase ín atríal fibríllatíon events (RR=0.73, 95% CI=0.52-1.05, P=0.24, I2=29%), and myocardial infarction (RR=1.10, 95% CI=0.80-1.51, P=0.57, I2=81%). However, PCC use was associated with reduced intensive care unit length of stay (MD=-0.81 days, 95% CI=-1.48- -0.13, P=0.02, I2=0%), bleeding (MD=-248.67 ml, 95% CI=-465.36- -31.97, P=0.02, I2=84%), and intra-aortic balloon pump/extracorporeal membrane oxygenation (RR=0.65, 95% CI=0.42-0.996, P=0.05, I2=0%) when compared with non-PCC treatment regimens. CONCLUSION: The use of PCC in cardiac surgery did not correlate with mortality, length of hospítal stay, thoracic drainage, atríal fibríllatíon, myocardíal ínfarction, and thromboembolíc events. However, PCC sígnificantly improved postoperatíve intensíve care unít length of stay, bleedíng, and intra-aortic balloon pump/ extracorporeal membrane oxygenation outcomes ín patients undergoing cardíac surgery.

Identification of two novel BTV16-specific B cell epitopes using monoclonal antibodies against the VP2 protein.

The VP2 protein of bluetongue virus (BTV) is an important structural protein and is the principal antigen responsible for BTV serotype specificity. In this study, we mapped the reactivity of two BTV16-specific monoclonal antibodies (MAbs) and identified two novel serotype-specific linear B cell epitopes on the BTV16 VP2 protein. By screening a series of peptides derived from the BTV16 VP2 protein and expressed as mannose-binding protein fusions, we determined that the linear epitopes recognized by the VP2-specific MAbs 3 G10 and 2B4 were located within the peptides 34EWSGHDVTEIPNRRMF49 and 540KNEDPYVKRTVKPIRA555, respectively. To define the minimal region required for antibody binding within these peptide regions, a series of progressively shorter peptides were synthesized and evaluated for 3 G10 and 2B4 binding. This work defined the motifs 34EWSGHDVTEIPNRRMF49 and 543DPYVKRTVK555 as the minimal linear peptides required for 3 G10 and 2B4 binding, respectively. Alignment of amino acid sequences from a number of BTV16 strains isolated from different regions indicated that these two epitopes are highly conserved among BTV16 strains. Furthermore, these two epitopes are not conserved among other BTV serotypes or prototype members of the genus Orbivirus in the family Reoviridae, as shown by sequence alignments. The MAb reagents and linear epitopes defined here provide the basis for the development of epitope-based serotype-specific differential diagnostic tools and may be useful in the design of epitope-based vaccines.

[Change in gastrocnemius dystrophin and metabolic enzymes and increase in high-speed exhaustive time induced by hypoxic training in rats].

The aim of the present study was to explore the changes and roles of dystrophin and membrane permeability in hypoxic training. Seventy-two 8-week-old Sprague Dawley (SD) rats were randomly divided into 4 groups, normoxic non-train (NC), normoxic train (NT), hypoxic non-train (HC), and hypoxic train (HT) groups. The rats of each group were randomly divided into three subgroups, non-exhaustive, low-speed exhaustive test and high-speed exhaustive test subgroups. Rats in hypoxia groups lived and were trained in a condition of 12.7% oxygen concentration (equal to the 4 300 m altitude). NT and HT groups received 4 weeks of training exercise. Then the rats in all non-exhaustive subgroups were sacrificed, and gastrocnemii were sampled for the measurements of lactate dehydrogenase (LDH), succinatedehydrogenase (SDH), malate dehydrogenase (MDH) activities. Moreover, serum LDH activity was analyzed. Low-speed exhaustive test and high-speed exhaustive test subgroups received exhaustive tests with 20 (71% VO2max) and 30 m/min speed (86% VO2max), respectively, and their exhaustive times were recorded. The results showed that, compared with normoxic groups, the weights in hypoxia groups exhibited slower increase. The level of dystrophin in HT group without exhaustion test didn't change significantly. The muscle MDH activities were markedly affected by the different oxygen concentration, training and their interaction (P < 0.05), whereas the muscle LDH activities were only affected by the different oxygen concentration (P < 0.05). Serum LDH activities were affected by the interaction of the different oxygen concentration and training (P < 0.05), showing decreased muscle LDH and increased blood LDH activities. The exhaustion time were markedly affected by the different test speed, training and their interaction (P < 0.05), and also affected by the interaction of the different oxygen concentration and training (P < 0.05), but didn't affected by oxygen concentration. The exhaustive time of HT high-speed exhaustive test subgroup was more than NT high-speed exhaustive test subgroup in 30 m/min exhaustion test. Compared with NT high-speed exhaustive test subgroup, HT high-speed exhaustive test subgroup had an earlier fatigue in the test, but had a rapid recovery. These results suggested that hypoxic training can effectively increase the rats' high-speed exhaustive time. The mechanism may be related to an increase in serum LDH caused by the increased membrane permeability after hypoxic training.

[Effects of heavy-load exercise on skeletal muscle cells apoptosis and mechanisms of mitochondrial apoptosis in rats].

OBJECTIVE: To analyze the molecular mechanisms of skeletal muscle cells apoptosis induced by heavy-load exercise with Omi as the entry point. METHODS: One hundred and twenty-six adult SD rats were randomly divided into five groups: control group(C), eccentric exercise group (E), simple blocking group (U), DMSO group (D) and exercise block group (EU). In addition to the C group, the other four groups were randomly divided into 0 h after experiment, 12 h after experiment, 24 h after experiment, 48 h after experiment and 72 h after experiment with 6 rats in each group. E and EU group were submitted to a heavy-load exercise on a treadmill down a 16° decline, 16 m/min for 90 minutes. U, D and EU group were one-time intervened with drugs. U and EU groups were intraperitoneally injected with 1.5 µmol/kg ucf-101, D group were intraperitoneally injected with 1.5 µmoL/kg 0.5% DMSO. The rats were sacrificed in batches at different time points after experiment, then the soleus were saved to detect the Caspase-3,-8,-9,-12 activities and protein expressions of Omi and XIAP. RESULTS: Compared with group C, the mitochondrial distribution and morphology appeared the typical ultrastructure pathological changes, the opening degree of MPTP was increased significantly (P＜0.01) or (P＜0.05), protein expressions of Omi and XIAP were increased significantly (P＜0.01 or P＜0.05), the activities of Caspase-9 and Caspase-3 were increased significantly (P＜0.01 or P＜0.05) in group E. Compared with group C, there was no significant difference in XIAP protein and caspase-9, - 3 activities in group U and Group D. The change trend of XIAP protein and Caspase-9, - 3 activities was the same as those between EU group and E group, but the change range of XIAP protein in EU group was significantly higher than that in E group (P＜0.01), and the change ranges of caspase-9, - 3 activities in EU group were significantly lower than those in E group (P＜0.01). CONCLUSION: A single heavy-load exercise can induce changes in the mitochondria morphology and structure in rats, open the high permeability of MPTP, and improve the expression of Omi protein, then through its downstream XIAP-Caspase pathway, start the mitochondrial apoptosis pathway mediated by caspase-9, and finally lead to myocyte apoptosis. The inhibition of Omi can reduce the cell apoptosis level of motor induced skeletal muscle cells.

A Review of the Role of Endo/Sarcoplasmic Reticulum-Mitochondria Ca2+ Transport in Diseases and Skeletal Muscle Function.

The physical contact site between a mitochondrion and endoplasmic reticulum (ER), named the mitochondria-associated membrane (MAM), has emerged as a fundamental platform for regulating the functions of the two organelles and several cellular processes. This includes Ca2+ transport from the ER to mitochondria, mitochondrial dynamics, autophagy, apoptosis signalling, ER stress signalling, redox reaction, and membrane structure maintenance. Consequently, the MAM is suggested to be involved in, and as a possible therapeutic target for, some common diseases and impairment in skeletal muscle function, such as insulin resistance and diabetes, obesity, neurodegenerative diseases, Duchenne muscular dystrophy, age-related muscle atrophy, and exercise-induced muscle damage. In the past decade, evidence suggests that alterations in Ca2+ transport from the ER to mitochondria, mediated by the macromolecular complex formed by IP3R, Grp75, and VDAC1, may be a universal mechanism for how ER-mitochondria cross-talk is involved in different physiological/pathological conditions mentioned above. A better understanding of the ER (or sarcoplasmic reticulum in muscle)-mitochondria Ca2+ transport system may provide a new perspective for exploring the mechanism of how the MAM is involved in the pathology of diseases and skeletal muscle dysfunction. This review provides a summary of recent research findings in this area.

[Effects of acupuncture on endoplasmic reticulum pathway in exercise-induced skeletal muscle damage in rats and its mechanism].

Objective: To observe the effects of acupuncture on the endoplasmic reticulum (ER) functional enzymes sarcoplasmic reticulum Ca2+-ATPase (SERCA), protein disulfide isomerase (PDI), glucose-regulated protein 78(GRP78) and PERK pathways in rats with exercise-induced skeletal muscle damage, and to explore the mechanisms of acupuncture in preventing and treating exercise-induced skeletal muscle damage. Methods: Eight-week-old male SD rats were randomly divided into control group (group C, n=6), exercise group (group E, n=30), acupuncture group (group A, n=30) and exercise acupuncture group (group EA, n=30). Among them, the E and EA group were established an exercise-induced skeletal muscle damage model by a single eccentric exercise, and acupuncture intervention was applied 0.5 cm above the Achilles tendon of the rat's calf immediately after EA exercise, and in group A, acupuncture intervention was applied during the same period. Each group was divided into 0 h/12 h/24 h/48 h/72 h (n=6) according to different sampling time points after exercise and acupuncture intervention, and soleus muscle was collected at the corresponding time for index test. The ultrastructure of muscle fibers was observed by transmission electron microscopy; the contents of SERCA and PDI were determined by ELISA; and the expressions of ER stress marker proteins GRP78 and p-PERK and p-eIF2α were detected by Western blot. Results: Compared with group C, there were no significant differences in the indicators of group A at all time points (P＞ 0.05), the ultrastructure of muscle fibers in group E showed different damages, SERCA content was significantly decreased from 0 h to 48 h (P＜0.05), PDI content was significantly increased from 0 h to 72 h (P＜0.05), GRP78 expression was significantly increased from 0 h to 72 h (P＜0.05), p-PERK expression was significantly increased from 0 h to 24 h (P＜0.05), and p-eIF2α expression was consistent with p-PERK. Compared with the corresponding times in group E, the ultrastructure of muscle fibers in group EA was significantly alleviated, SERCA content was significantly increased from 48 h and 72 h (P＜0.05), PDI content was significantly increased from 0 h to 72 h (P＜0.05), and GRP78 expression was significantly decreased from 0 h to 72 h (P＜0.05). Conclusion: Acupuncture can effectively ameliorate exercise-induced skeletal muscle damage and alleviate ER stress after a large load eccentric exercise. The mechanism of them may be related to the up-regulation of protein disulfide isomerase PDI and the inhibition of ER stress PERK pathway.

[TGF-ß1/ERK/CTGF pathway involved in effect of acupuncture on exercise-induced skeletal muscle fibrosis].

OBJECTIVE: To observe the changes of the skeletal muscle fibrosis and changes of transforming growth factor-ß1(TGF-ß1)/ extracellular signal-regulated kinase (ERK) / connective tissue growth factor (CTGF)pathway in rats after long-term eccentric exercise and acupuncture intervention, so as to explore the mechanism of acupuncture in regulating exercise-induced skeletal muscle fibrosis. METHODS: A total of 30 male SD rats were randomly divided into normal control, exercise and acupuncture group, with 10 rats in each group. The rat model of skeletal muscle fibrosis was established by eccentric exercise for 3 weeks. After exercise trained every time, the rats of the acupuncture group received acupuncture stimulation by holding the acupuncture needle to obliquely and longitudinally penetrate the ventral part of triceps of the lower leg along its lateral side, followed by retaining the needle for 2 min. Changes of the collagen fibers in each group was observed by scanning electron microscope. The expressions of Collagen Ⅰ, TGF-ß1, phosphated (p)-ERK/ERK and CTGF proteins were detected by Western blot. RESULTS: After 3 weeks of eccentric exercise and acupuncture, the fibrosis and deposition of collagen fibers in the exercise group were significantly higher than that in the normal control group,the degree of fibrosis in the acupuncture group was significantly lower than that in the exercise group. Compared with the normal control group, the expression levels of Collagen Ⅰ, TGF-ß1, CTGF and p-ERK/ERK in the exercise group was significantly higher (P<0.01，P<0.05). After EA interventions, the increased levels of the above indicators were significantly reversed (P<0.05，P<0.01) apart from p-ERK/ERK which had a downward trend, but the difference was not statistically significant. CONCLUSION: The accumulation of chronic sports injury can lead to the deposition of collagen fibers in skeletal muscle, which leads to the fibrosis of skeletal muscle. Acupuncture can inhibit skeletal muscle fibrosis via down-regulating TGF-ß1/ERK/CTGF signaling pathway.

Integrin-alpha5 mediates epidermal growth factor-induced retinal pigment epithelial cell proliferation and migration.

Proliferation and migration of retinal pigment epithelial (RPE) cells play a crucial role in proliferative vitreoretinopathy (PVR)-related pathology. Cytokines, including EGF, can result in RPE cell activation and cause PVR. In this study, integrin-alpha(5) expression was first studied in PVR membranes by immunofluorescence. Then the effect of EGF on integrin-alpha(5) expression was determined by flow cytometry, Western blot analysis and the reverse-transcription polymerase chain reaction (RT-PCR) in the ARPE-19 cell line. Proliferation and migration of ARPE-19 cells were measured by the methylthiazolyldiphenyl-tetrazolium bromide and Boyden chamber assays. We found that a higher level integrin-alpha(5) was present at the RPE cell surface in PVR compared with normal retina. EGF could dose dependently increase integrin-alpha(5) mRNA and protein levels in vitro. EGF promoted ARPE-19 cell proliferation and migration. Neutralizing integrin-alpha(5) by specific anti-integrin-alpha(5) antibody abolished most of the effects of EGF. The study provided evidence that EGF might influence PVR by promoting integrin-alpha(5) expression and subsequent proliferation and migration of RPE.

[Changes of dystrophin and desmin in rat gastrocnemius under micro-damage induced by hypoxia].

To explore the changes and regulation mechanism of dystropin and desmin under muscle injury without mechanic stress, 40 male Sprague-Dawley rats were randomly divided into 5 groups, which included normoxia control and hypoxia groups for 1, 2, 4 and 7 d with 10% O2. Two rats from each group were examined for sarcolemma integrity using Evans blue dye (EBD) and EBD-positive fiber typing by metachromatic dye-ATPase method. The rest six rats from each group were analyzed for the changes of protein content and gene expression using Western blot, RT-PCR and fluorescence assays. The results showed that the EBD-positive muscle fibers, mainly type IIA and type IIB, appeared at 1 d after hypoxia exposure. Both the ratio of EBD-positive cell and the mean fluorescence density were significantly higher in hypoxia groups than those in control group (P<0.05). The contents of dystrophin and desmin fluctuated after hypoxia exposure, increased at 1 d, decreased at 2 d, increased dramatically again at 4 d, and returned to a normal level at 7 d. Consistently, the gene expression began to increase significantly after 2 d. The total activity of calpain was significantly higher in hypoxia groups at 1, 4 and 7 d. Significantly higher levels of HSP70 and HSP90 were also observed at 4 and 7 d, respectively (P<0.05). These results suggest that the mechanical stress is not the only cause of damage of sarcolemma membrane integrity. In contrast to eccentric contraction, hypoxia-induced muscle damage is not accompanied by the loss of dystrophin and desmin. The types of muscle fibers recruited by motor units and the activities of calpain may be important in hypoxia-induced damage of sarcolemma membrane integrity.

Mechanical Properties and Failure Behavior of 3D-SiCf/SiC Composites with Different Interphases.

Continuous silicon carbide fiber-reinforced silicon carbide ceramic matrix composites (SiCf/SiC) are promising as thermal structural materials. In this work, the microstructure and static mechanical properties of 3D-SiCf/SiC with PyC, SiC, and PyC/SiC and without an interface prepared via polymer infiltration and pyrolysis (PIP) were investigated systematically in this paper. The results show that the microstructure and static mechanical properties of SiCf/SiC with an interphase layer were superior to the composites without an interlayer, and the interface debondings are existing in the composite without an interphase, resulting in a weak interface bonding. When the interphase is introduced, the interfacial shear strength is improved, the crack can be deflected, and the fracture energy can be absorbed. Meanwhile, the shear strength of the composites with PyC and PyC/SiC interfaces was 118 MPa and 124 MPa, respectively, and showing little difference in bending properties. This indicates that the sublayer SiC of the PyC/SiC multilayer interface limits the binding state and the plastic deformation of PyC interphase, and it is helpful to improve the mechanical properties of SiCf/SiC.