TAZ and myostatin involved in muscle atrophy of congenital neurogenic clubfoot

BACKGROUND Muscular atrophy is the basic defect of neurogenic clubfoot.Muscle atrophy of clubfoot needs more scientific and reasonable imaging measurement parameters to evaluate.The Hippo pathway and myostatin pathway may be directly correlated in myogenesis.In this study,we will use congenital neurogenic clubfoot muscle atrophy model to verify in vivo.Further,the antagonistic mechanism of TAZ on myostatin was studied in the C2C12 cell differentiation model.AIM To identify muscle atrophy in fetal neurogenic clubfoot by ultrasound imaging and detect the expression of TAZ and myostatin in gastrocnemius muscle.To elucidate the possible mechanisms by which TAZ antagonizes myostatin-induced atrophy in an in vitro cell model.METHODS Muscle atrophy in eight cases of fetal unilateral clubfoot with nervous system abnormalities was identified by 2D and 3D ultrasound.Western blotting and immunostaining were performed to detect expression of myostatin and TAZ.TAZ overexpression in C2C12 myotubes and the expression of associated proteins were analyzed by western blotting.RESULTS The maximum cross-sectional area of the fetal clubfoot on the varus side was reduced compared to the contralateral side.Myostatin was elevated in the atrophied gastrocnemius muscle,while TAZ expression was decreased.They were negatively correlated.TAZ overexpression reversed the diameter reduction of the myotube,downregulated phosphorylated Akt,and increased the expression of forkhead box O4 induced by myostatin.CONCLUSION Ultrasound can detect muscle atrophy of fetal clubfoot.TAZ and myostatin are involved in the pathological process of neurogenic clubfoot muscle atrophy.TAZ antagonizes myostatin-induced myotube atrophy,potentially through regulation of the Akt/forkhead box O4 signaling pathway.

Correlation Analysis Between BDNF and Postoperative Cognitive Dysfunction in Aged Rats

Objective:To investigate the relationship between BDNF and postoperative cognitive dysfunction among aged rats.Methods:36 SPF healthy aged male SD rats were randomly assigned to a control group and a model group,respectively,with 18 rats in each group.Abdominal exploration was performed on the rats in the model group after anesthesia,while the rats in the control group were not operated on after anesthesia.The escape latency and swimming distance of the two groups were analyzed on a day prior to surgery as well as on the first day,third day,and seventh day following surgery;the expression levels of BDNF protein in the hippocampus of rats in the two groups were compared on the first day,third day,and seventh day following surgery;the correlation between BDNF and escape latency and swimming distance was analyzed.Results:The escape latency and swimming distance of the rats in the control group on a day prior to surgery,the first day,third day,and seventh day following surgery did not differ significantly(p>0.05),but those in the model group had significant behavioral difference(p<0.05).On a day prior to surgery,the rats in both groups showed no significant behavioral difference in escape latency and swimming distance(p>0.05),but on the first day,third day,and seventh day following surgery,the escape latency and swimming distance of the rats in the model group were significantly longer than those in the control group(p<0.05).In the control group,there was no significant difference in the protein expression of BDNF in the hippocampus of rats on the first day,third day,and seventh day following surgery,but there was significant difference in the model group.On the first day,third day,and seventh day following surgery,the BDNF protein expression level in the rats’hippocampus of the control group was significantly higher than that of the model group(p<0.05).The data from Pearson correlation analysis confirmed that BDNF protein expression is negatively correlated with escape latency(r=-0.567,p<0.001)and swimming distance(r=-0.623,p<0.001).Conclusion:In aged rats,the BDNF protein expression level decreases,and the degree of cognitive dysfunction increases after surgery.

Effects of Different Doses of BDNF on Postoperative Cognitive Function in Aged Rats Undergoing Abdominal Surgery

Objective:To investigate the effects of different doses of BDNF on postoperative cognitive function in aged rats undergoing abdominal surgery.Methods:72 aged healthy male SD rats of SPF grade were selected.According to the random number table method,the rats were randomly divided into the control group,model group,low dose BDNF injection group,and high dose BDNF injection group,with 18 rats in each group.The model group,low dose group,and high dose group underwent abdominal surgery after anesthesia,and 5μL/time of BDNF was intranasally administered to the rats in the low dose and high dose groups 6 hours after abdominal surgery,of which the dose of the low dose group was 0.1 g/L,while that of the high dose group was 0.2 g/L.The drug was administered alternately through both nostrils,with an interval of 2 minutes each time,for 5 times.The control group did not undergo surgery after anesthesia.The escape latency and swimming distance of the four groups of rats were compared before surgery,the first day,the third day,and the seventh day after surgery;similarly,the BDNF protein expression level in the hippocampus of the four groups of rats was compared on the first day,the third day,and the seventh day after surgery.Results:The escape latency and swimming distance of the control group were not statistically significant on the first day,the third day,and the seventh day after surgery,p>0.05;the escape latency and swimming distance of the model group,low dose group,and high dose group on the first day,the third day,and the seventh day after surgery were statistically significant,p<0.05.Before surgery,the escape latency and swimming distance of the four groups were not statistically significant,p>0.05;on the first day,the third day,and the seventh day after surgery,the escape latency and swimming distance of the model group>low dose group>high dose group>control group,p<0.05.The BDNF protein expression level in the hippocampus of the control group on the first day,the third day,and the seventh day after surgery showed no statistical significance p>0.05;the expression level of BDNF protein in the hippocampus of the model group,low dose group,and high dose group on the first day,the third day,and the seventh day after surgery was statistically significant,p<0.05.On the first day,the third day,and the seventh day after surgery,the expression level of BDNF protein in the hippocampus of the model group<low dose group<high dose group<control group,p<0.05.Conclusion:Compared with 0.1 g/L of BDNF,0.2 g/L of BDNF can improve the postoperative cognitive function of aged rats undergoing abdominal surgery.

Anti-Anxiety Effects of Prelimbic 5-HT4 Receptors in the Rat Model of Parkinson’s Disease: Evidence from Behavioral and Electrophysiological Study

Objective:Clinical and laboratory studies have demonstrated that prelimbic(PrL)and serotonin-4(5-HT4)receptors may have the key role in regulating anxiety.However,the pathophysiology of anxiety in Parkinson’s disease(PD)remains obscure.In this research,the effects of PrL 5-HT4 receptors on anti-anxiety behaviors in hemiparkinsonian rats were investigated.Methods:PD model rats were used as the research subjects,starting with behavioral changes,from the point of view of electrophysiology,the regulatory effect of PrL 5-HT4 receptors on PD-related anxiety and the possible mechanism were explored.Results:Anxiety-like behaviors were induced via MFB lesion in rats.Intra-PrL injection of 5-HT4 receptors agonist RS67333 induced anti-anxiety effects in both sham and PD group.In the sham group,PrL administration of 5-HT4 receptors antagonist SB204070 produce anti-anxiety effects,but in the PD group,the expression of anxiety-like behavior was increased.Compared to the sham group,the effective dose of the behavioral effects of the two drugs in the PD group was obviously higher.Electrophysiological data suggested that PrL administration of RS67333(SB204070)increased(decreased)the firing activities ofγ-aminobutyric acid(GABA)neurons in both groups.Compared with rats in sham group,lesioned rats had a shorter duration of the excitation(inhibition)effects on firing activities of GABA neurons.Conclusion:PrL 5-HT4 receptors regulate anxiety behaviors in PD rats,and its mechanism may be related to the down-regulation of expression or function of PrL 5-HT4 receptors in PD.

An aircraft brake control algorithm with torque compensation based on RBF neural network

The wheel brake system of an aircraft is the key to ensure its safe landing and rejected takeoff.A wheel’s slip state is determined by the brake torque and ground adhesion torque,both of which have a large degree of uncertainty.It is this nature that brings upon the challenge of obtaining high deceleration rate for aircraft brake control.To overcome the disturbances caused by the above uncertainties,a braking control law is designed,which consists of two parts:runway surface recognition and wheel’s slip state tracking.In runway surface recognition,the identification rules balancing safety and braking efficiency are defined,and the actual identification process is realized through recursive least square method with forgetting factors.In slip state tracking,the LuGre model with parameter adaptation and a brake torque compensation method based on RBF neural network are proposed,and their convergence are proven.The effectiveness of our control law is verified through simulation and ground experiment.Especially in the experiments on the ground inertial test bench,compared to the improved pressure-biased-modulation(PBM)anti-skid algorithm,fewer wheel slips occur,and the average deceleration rate is increased by 5.78%,which makes it a control strategy with potential for engineering applications.

Cu-10Sn-4Ni-3Pb Alloy Prepared by Crystallization Under Pressure: An Experimental Study

The wear-resistant tin bronze （Cu-10Sn-4Ni-3Pb） with tin content above 8 wt.% prepared by traditional melting and casting process usually defects such as low density, poor properties and segregations. The crystallization under pressure processing of Cu-10Sn-4Ni-3Pb alloy was investigated. The microstructures were observed and analyzed and compared with that by traditional melting and casting process. The results show that the dendrite has obviously disappeared and the dendritic segregation alleviated by using the crystallization under 680 MPa pressure process, in comparison with the remarkably dendrite microstructure and severe as-cast defects of alloy prepared by traditional melting and casting technology. Based on the experimental study, the properties and microstructures of Cu-10Sn-4Ni-3Pb tin bronze prepared by crystallization under pressure have been improved significantly.