Interacting of receptor component protein and G protein in static pressure-induced proliferation of VSMC / 中国药理学通报

Aim To explore the effect of receptor component protein(RCP)in the signal transduction of vascular smooth muscle cell(VSMC)proliferation induced by static pressure.Methods The mouse-derived vascular smooth muscle cell line(A10VSMC)was employed in the experiment.Cells were exposed to static pressure,and MTT assay was used to detect the cell viability.Western blot was used to determine the expressions of PCNA,RCP and p-Akt,RCP mRNA was tested by RT-PCR,and co-immunoprecipitation was used to test the interaction between RCP and G proteins.Results The cell viability,expressions of PCNA and RCP increased with the elevation of static pressure and reached their peaks at 120 mmHg,and after 6 hours they got a plateau.The static pressure significantly increased the level of p-Akt,meanwhile,the binding of RCP and Gαs significantly decreased.However,the binding of RCP and Gβ increased in response to static pressure after stimuli of static pressure,but Gγ was obscure.Conclusion Static pressure can induce VSMC proliferation and expression of RCP,which may involve G protein signal transduction model.

Research progress of mechanism of hypoxia-inducible factor-1α signaling pathway in condylar cartilage growth and remodeling / 华西口腔医学杂志

The condylar cartilage was adapted to hypoxic conditions in vivo. However, condylar cartilage cells exposed in normoxia in vitro affect the chondrocyte phenotype and cartilage matrix formation. This condition also resulted in great difficulty in chondrocyte research. Culturing chondrocyte should be simulated in in vivo hypoxia environment as much as possible. The hypoxia-inducible factor-1α (HIF-1α) demonstrates an important transcription factor of adaptive response to hypoxic conditions. HIF-1α also plays an active role in maintaining homeostasis and function of chondrocytes. This review summarized current knowledge of the HIF-1α structure, signaling pathway, and mechanism of HIF-1α in the condylar cartilage repair.

Effects of static pressure on the expression of ET-1 and NO in cultured retinal microvascular endothelial cells / 眼科研究

Background Researches have demonstrated that ocular hypertension induces the ischemia-reperfusion of retina and further leads to the degeneration of retinal ganglion cells,but its mechanism is beyond understanding.Objective The present study aims to observe the effects of static pressure on the morphology,proliferation activity and viability of cultured retinal microvascular endothelial cells (RMECs) and evaluate the expression of ET-1 and NO in these cells under variant static pressure.Methods RMECs were isolated from 30 healthy Wistar rats and cultured using explant culture method by Ⅷ factor antibody and PECAM-1 antibody.The static pressure of 1.33kPa,2.67kPa,5.33kPa and 10.67kPa was used in culture bottle respectively.The RMECs without static pressure were used as normal control group.The morphology of RMECs under the different static pressure was observed by inverted phase contrast microscopy,and the number of RMECs was counted using the counting plate.Cellular viability was studied by trypan blue staining.The changes of ET-1 and NO_2~-/NO_3~-,two metabolic products of NO,in the medium were detected by radioimmunoassay and Griess's nitrate reductase method.The expression of ET-1,eNOS and iNOS mRNA in RMECs was analyzed by semi-quantitative RT-PCR 24 hours after treatment of variant static pressure.Results Cultured RMECs sticked well at 24 hours and reached to confluence at 48 hours and showed the red fluorescence for Ⅷ factor antibody and PECAM-1 antibody.Enlargement of nuclei,extenders of cell bodies and suspension of RMECs in medium were observed.The number of RMECs was gradually increased.The cell viability was reduced with the raise of static pressure among these four groups(F=12.205,P＜0.01;F=11.180,P＜0.01).The static pressure increased the content of ET-1 released by RMECs in 2.67kPa,5.33kPa and 10.67kPa of static pressure groups,and concentrations of NO_2~-/NO_3~- in the medium showed a significant increase in 5.33kPa and 10.67kPa of static pressure groups compared with normal and 1.33kPa of static pressure groups(P＜0.01).The expressions of ET-1 mRNA,eNOS mRNA and iNOS mRNA were considerably enhanced in 5.33kPa and 10.67kPa of static pressure groups compared with normal control group(P＜0.01).Conclusion Raised static pressure causes the alteration of RMGCs structure and morphology.Static pressure could upregulate the expressions of ET-1,eNOS and iNOS mRNA in RMECs and increase the release of ET-1 and NO.This pathway might be one of pathologic mechanisms of retinal injury induced by high intraocular pressure.

Clinical Implications of Inspiratory Muscle Training in Patients with Duchenne Muscular Dystrophy

Respiratory insufficiency is a common cause of morbidity and mortality in patients with Duchenne muscular dystrophy(DMD). In these patients, progressive muscle weakness is a major factor in the development of respiratory insufficiency. Therefore, the physical training program to improve the strength and endurance of respiratory muscle could conceivably improve respiratory function and prevent respiratory complication in patients with DMD. The purpose of this study is to examine the effects of inspiratory muscle training on respiratory function of DMD patients according to functional state. Eighteen DMD patients who were registered at the Muscle clinic of Yong Dong Severance Hospital were assessed for the pulmonary function using the routine pulmonary function test and measurements of maximal static pressures at 6 weeks before the training, at the beginning of training, and after the end of 6 week-training. The first 6 weeks were used as a control period. Inspiratory muscle training consisted of breathing through Threshold inspiratory muscle trainer (IMT) at 30% of patients' maximal inspiratory pressures(MIP) for 15 minutes twice a day and the 'endurance time' was recorded weekly for an assessment of inspiratory muscle endurance. This study showed significant improvement of MIP and endurance time after the training in both ambulatory and wheelchair-bound patients. The amounts of improvement were greater in the patients with a better functional state and greater baseline forced vital capacity. We conclude that, in the early stages of DMD, inspiratory muscle training with pressure threshold device is more useful when the forced vital capacity is well preserved.

Foot Pressure Distribution of Normal Children

The purpose of this study was to measure the foot pressure distribution of normal children. Static and dynamic pressure, dynamic pressure-time integral, relative impulse, static pressure distribution between forefoot and heel, and the percentage of contact time in each phase of the gait cycle were measured from 68 normal children by the in-sole pressure measurement system. The measurements were perfomed while standing and walking with their comfortable speed using the in-sole pressure measurement system. The sites of the greatest static pressure, dynamic pressure-time integral and relative impulse were obtained from the 2nd and the 3rd metatarsal head areas. And the dynamic pressure was obtained from in the lateral heel area. The forefoot to heel load ratio was about 6 to 4 in the static state. The contact time was greatest during the push-off phase.

Clinical Implications of Pulmonary Function Test and Maximum Static Pressure in Duchenne Muscular Dystrophy

Respiratory failure and pulmonary infection are the major causes of death in the Duchenne muscular dystrophy patients. The purposes of this study are to evaluate pulmonary function of Duchenne muscular dystrophy patients, to verify usefulness of the measurements of maximum static pressures and to define functional classes in Duchenne muscular dystrophy patients. Forty two Duchenne muscular dystrophy patients were assessed for pulmonary function by a routine pulmonary function test and the measurements of maximum static pressures. This study showed significant negative correlations between the subject's functional class and the values of forced vital capacity(FVC), maximum inspiratory and expiratory pressures(MIP and MEP). Significant reduction of maximum static pressures began earlier than FVC in the course of disease. The MEP was as low as 64% of the predicted value before FVC and MIP showed demonstrable decline. A pulmonary care program focusing on maintaining adequate respiratory pressures is suggested to start early for the child with Duchenne muscular dystrophy.