Mitochondrial-targeted and ROS-responsive nanocarrier via nose-to-brain pathway for ischemic stroke treatment

Oxidative stress injury and mitochondrial dysfunction are major obstacles to neurological functional recovery after ischemic stroke. The development of new approaches to simultaneously diminish oxidative stress and resist mitochondrial dysfunction is urgently needed. Inspired by the overproduced reactive oxygen species (ROS) at ischemic neuron mitochondria, multifunctional nanoparticles with ROS-responsiveness and mitochondrial-targeted (SPNPs) were engineered, achieving specific targeting delivery and controllable drug release at ischemic penumbra. Due to the nose-to-brain pathway, SPNPs which were encapsulated in a thermo-sensitive gel by intranasal administration were directly delivered to the ischemic penumbra bypassing the blood‒brain barrier (BBB) and enhancing delivery efficiency. The potential of SPNPs for ischemic stroke treatment was systematically evaluated in vitro and in rat models of middle cerebral artery occlusion (MCAO). Results demonstrated the mitochondrial-targeted and protective effects of SPNPs on H2O2-induced oxidative damage in SH-SY5Y cells. In vivo distribution analyzed by fluorescence imaging proved the rapid and enhanced active targeting of SPNPs to the ischemic area in MCAO rats. SPNPs by intranasal administration exhibited superior therapeutic efficacy by alleviating oxidative stress, diminishing inflammation, repairing mitochondrial function, and decreasing apoptosis. This strategy provided a multifunctional delivery system for the effective treatment of ischemic injury, which also implies a potential application prospect for other central nervous diseases.

Effect of abdominal mechanical stimulation on nervous system in irritable bowel syndrome-Diarrehea / 国际生物医学工程杂志

Objective:To observe the effect of abdominal mechanical stimulation on rats with irritable bowel syndrome-Diarrehea (IBS-D), and to explore the possible mechanism of abdominal massage mechanical stimulation to improve IBS-D.Method:60 newborn Wistar rats were randomly divided into blank group, model group and abdominal massage group, 20 rats for each group. The IBS-D rat model was established by separating the mother rats and newborn rats. In the abdominal massage group, the IBS-D rats were treated with abdominal rubbing once a day for 14 days. In the model group, the IBS-D rats were only bound to the experimental platform once a day for 5 min for 14 days. The rats in blank group were not made model and with no intervention. The intestinal motility and visceral sensitivity of rats were measured by the time of glass bulb expulsion and the abdominal lift volume threshold. The pathological changes of rat colon tissue were observed by hematoxylin-eosin staining. The changes of mast cells in colon tissue were observed by toluidine blue staining. The ultramicrostructure of intestinal glial cells was observed by transmission electron microscope. The content of proinflammatory factors IL-6 and IL-1β in rat plasma was determined by ELISA.Results:Compared with the model group, mechanical stimulation of the abdominal massage can significantly prolong the discharge time of the glass beads [(2.5±0.2) min vs (1.6±0.2) min], increase the abdominal lift volume threshold of rats [(0.5±0.1) ml vs (0.4±0.1) ml], improve the pathological state of the colon tissue, and reduce the number of mast cells [(2.64±0.22) per field vs (5.61±0.12) per field], reduce the number of mitochondria in the intestinal glial cells and increase the density of heterochromatin, and can also reduce the secretion of proinflammatory factors IL-6 [(189.4±4.7) pg/ml vs (224.8±8.6) pg/ml] and IL-1β [(178.4±7.1) pg/ml vs (191.4±8.4) pg/ml], and the differences were statistically significant (all P<0.05). Conclusions:Mechanical stimulation of abdominal massage can increase the visceral sensitivity of IBS-D rats, regulate intestinal glial cells and reduce the secretion of proinflammatory factors. The mechanism may be related to the intestinal-brain axis.

Effects of abdominal massage on the structure and function of affective loop in rats with generalized anxiety disorder / 国际生物医学工程杂志

Objective:To observe the structural and functional changes of each nucleus group in generalized anxiety disorder(GAD) rat models before and after the massage therapy, and to explore the central regulating mechanism of the massage therapy in GAD.Methods:60 Wistar male rats were randomly divided into blank group, model group and abdominal rubbing group, 20 rats for each group. GAD rat models were established by chronic emotional stress, and the models were evaluated by the elevated cross maze experiment. In the abdominal rubbing group, the GAD rats were treated with abdominal rubbing once a day for 10 min for 14 days. In the control group, the GAD rats were only bound to the experimental platform once a day for 10 min for 14 days. Horseradish peroxidase (HRP) retrograde tracking marker method was used to detect the changes of the structure of each nuclear cluster in the affective loop of the GAD rats in each group. The liquid-mass spectrometry quantitative analysis was used to determine the relative concentrations of N-acetyl aspartate (NAA), glutamic acid, choline and creatine in nuclear cluster of the GAD rats in each group.Results:Compared with the blank group, the HRP labeled cells in the rats of model group were less expressed and the activity of the emotional circuit in the brain was weak. The NAA/creatine ratio in the left hippocampal tissue of the rats in the model group was significantly increased than that of the blank group(0.94±0.08 vs 0.79±0.10, P<0.05), the glutamic acid/creatine ratio in the right hippocampal tissue was significantly decreased (0.95±0.10 vs 1.12±0.13, P<0.01), and the NAA/creatine andglutamic and acid/creatineratios in the left cortical tissue were all significantly decreased (1.04±0.05 vs 1.41±0.23, and 1.21±0.04 vs 1.57±0.11, all P<0.01). Compared with the model group, the hippocampal tissues of the GAD rats in the abdominal rubbing group had a large number of HRP aggregation and spread to the surrounding tissues, the NAA/creatine and glutamic acid/creatine ratios in the left hippocampal tissue of the abdominal rubbing group were significantly decreased (0.74±0.21 vs 0.94±0.09 and 0.92±0.20 vs 1.21±0.12, all P<0.01). The differences between the model group and the abdominal rubbing group in the ratio of glutamic acid/creatine in the right hippocampal tissue (1.01±0.23 vs 0.95±0.10), the ratio of NAA/creatine in the left cortical tissue (1.12±0.09 vs 1.04±0.05), and the ratio of glutamic acid/creatine in the left cortical tissue (1.22±0.12 vs 1.21±0.04) were not statistically significant ( P>0.05). Conclusions:Abdominal rubbing can effectively enhance the activity of affective loop and improve the relative concentration of neuron metabolites in hippocampal and cortical tissues in the affective loop, suggesting that the mechanism of GAD treatment by abdominal rubbing may be closely related to the structure and function of regulating affective loop.

Molecular mechanism of the combination of mechanical strain stimulation and icariin on inhibiting the differentiation of osteoclasts induced by fatigue load stimulation / 国际生物医学工程杂志

Objective To investigate the effect and molecular mechanism of the combination of mechanical strain stimulation and icariin (ICA) on inhibiting the differentiation of osteoclasts induced by fatigue load stimulation. Methods The mouse mononuclear macrophage cell line RAW264.7 was cultured in vitro, and the blank control group was α-MEM complete medium. In the fatigue load group, RAW264.7 cells were treated with 5000 μεmechanical stretch strain, and then cultured in an osteoclast culture medium that was an α-MEM complete medium containing 40 ng/ml macrophage colony-stimulating factor and 40 ng/ml osteoclast differentiation factor. In the mechanical stimulation + ICA group, RAW264.7 cells were treated as the same procedure in the fatigue load group, and then cultured in an α-MEM complete medium containing 1 ×10 -5 mol/L ICA simultaneously with a 1000 μεtensile strain on the substrate. The activity of tartrate-resistant acid phosphatase (TRAP) was detected using a TRAP assay kit. The mRNA expression of the osteoclast marker genes, i.e. TRAP, cathepsin K(CTSK) and matrix metalloproteinase 9 (MMP-9) was detected by real-time RT-PCR. The nuclear translocation of nuclear factor kappa B (NF-κB) was analyzed by Western Blot. Results Compared with the fatigue load group, the combination of mechanical stimulation (1000 με substrate stretching) and ICA (1×10-5 mol/L) could significantly inhibit the activity of TRAP in osteoclasts (P<0.01) and reduce osteoclastosis. Moreover, that combination not only could down-regulate the mRNA expression of TRAP, CTSK and MMP-9 and the differences were statistically significant (all P<0.01), but also could inhibit the formation of osteoclasts by inhibiting the phosphorylation of P65, P50 and IκB-α in NF-κB signaling pathway. Conclusions The coupling of mechanical stimulation and ICA can effectively inhibit the osteoclast differentiation and the bone resorption induced by fatigue load, and the mechanism may involve regulating NF-κB signaling pathway.

Progress in impact mechanism of CKIP-1 gene on osteoporosis / 国际生物医学工程杂志

Osteoporosis (OP) is one of the bone metabolic diseases which seriously harms the health and lives of people. The main cause of OP is that the balance between bone formation and bone absorption, i.e. the balance of the bone remodeling process,is no longer exist. When the bone absorption dominates the process, it will lead to osteopenia, destruction of bone microstructure and increased rate of fracture. Previous studies have shown that casein kinase 2-interacting protein-1 (CKIP-1) plays an important role in the process of bone tissue proliferation and differentiation. It mainly interacts with Smad ubiquitination regulatory factor 1 (Smurf 1) to affect bone metabolism. This review analyzes and summarizes the impact of CKIP-1 on bone tissue osteogenic differentiation direction and its mechanism, which may provide new idea and research orientation for future clinical treatment of osteoporosis.

Effects of microgravity on bone marrow mesenchymal stem cells into osteogenic differentiation / 国际生物医学工程杂志

Bone marrow mesenchymal stem cells (BMSCs) is a kind of multipotent adult stem cells,which is one of the most important seed sources of tissue engineering.Microgravity has inhibitory effects on osteogenic differentiation of BMSCs,which will cause bone mass reduction and changes of bone micro-structure that finally lead to osteoporosis.This process is regulated by multiple signaling pathways such as mitogen-activated protein kinase (MAPK) pathway,Notch pathway and Wnt/β-catenin pathway which co-regulated BMSCs osteogenic differentiation under microgravity.Studying the effects of microgravity on BMSCs into osteogenic differentiation can clarify the mechanism of bone loss,put forward new targets for the treatment of diseases and provide a useful reference for the development of China's space industry.