| [Objective]As the development of the technology of submarine escape, simulate various navies to advance in deeper sea with the technology of submarine escape, and one of the barriers along the obstacle is bubble injury in decompression sickness. The mechanism of decompression sickness:10 meters diving in human, roughly equals to the increase of an atmospheric pressure. The body in a high pressure environment, partial pressure of variety gas in alveoli increased, and immediately got a balance pressure with compressed air inhaled. Because the alveolar gas pressure is higher than the gas in the blood, a corresponding increase in the amount of gas dissolved in in the blood. When the human rapidly decompressed from high pressure environment and the pressure inside is higher than outside, in a few seconds to a few minutes free gas produced,and the gas bubbles accumulated in tissues and blood. The oxygen and carbon dioxide in the gas bubbles are most rapidly absorbed by hemoglobin and other plasma composition.Only a small amount of them stay in the physical form free in body fluids.while nitrogen is inert gas can not beabsorbed by the organization, it can exist long-term in a bubble state. The bubbles can be aggregated to form embolism in blood vessels, blocking blood circulation. Them can cause the dysfunction of vascular endothelial cell,and endothelial dependent vasodilation ability is reduced.It resultes ischemia、edema and hemorrhage in distal tissue,and can even cause nitrogen excretion disorder. There are some studys say bubbles can be caused activation of platelet and platelet aggregation,which was definited as bubble-induced platelet aggregation(BIPA).It can further block blood vessels, and ti is an important mechanism for the formation of decompression sickness.Yifei Huoxue granule,originated by Academician Dong Jianhua base on his calinical exprence,is compound promoting blood circulation and removing bold stasis for lung mainly used for the treatment of chronic pulmonary heart disease and pulmonary hypertension.The latest research show it can make blood vessels diastolic,reducing the pulmonary arterial pressure.Modern medical research shows that Ligustrazine is the four methyl pyrazine alkaloids frommonomer extracted and separated from Chuanxiong rhizome, and it is a clinical traditional Chinese medicine commonly used in promoting blood circulation and removing blood stasis. Ligustrazineis can dilate blood vessels, increasing blood flow in the coronary and cerebral, inhibiting platelet aggregation, reduceing platelet activity and blood viscosity, improving microcirculation and blood rheology. Considering The impotance of BIPA in the mechanism of decompression sickness after submarine escape and the effect of promoting blood circulation in YFHXG.we decide to study whether YFHXG can intervent decompression sickness.Domestic and foreign scholars generally think unsafe decompression can cause bubble formation in blood vessels and tissues. Many related research shows no-matter weather the bubble diameter is greater than the blood vessels, the number,flow rate,flow direction entirely depends on the function of blood vessels.blood pressure. Under the action of blood pressur and blood fow,Bubbles can easily get through blood vessels by deformation. Only when vascular occluse and bubble get no way out and blood pressure is less than the force of vascular closure, the bubble can be a static state.And this can cause DCS symptoms. Therefore, we speculate whether decompression sickness can effect vasodilatory capacity. Vasodilation is divided into endothelium dependent vasodilatation and non endothelium dependent vasodilation. Endothelium dependent vasodilation caused by acetylcholine, bradykinin stimulation, which mainly cause vasodilation mediated physiological stimulation. NO is an important factor of endothelium-dependent relaxation. NO was synthesized by nitric oxide synthase (NOS). NOS including eNOS,iNOS, nNOS type three.nNOS is the nerve type, located in neurons; iNOS is inducible, can be induced in pathological state of inflammation; eNOS is stably expressed in vascular endothelial cells, which can synthesis physiological requirements of NO.The dimer of eNOS can change L-arginine into NO, NO is an important factor of endothelium-dependent relaxation. NO by nitric oxide synthase (NOS) synthesis, stable expression of eNOS in vascular endothelial cells can synthesis, physiological requirements of NO, eNOS in the two dimers form the L-arginine into NO. When eNOS is dissociated into monomers, it can not synthesis NO and generate a large amount of superoxide anion and O2-,02-and NO reaction to generate a large amount of ONOO-.Nitride modificate important proteins and change signaling pathways,which mediated cytotoxic effect of NO directly or indirectly. The studies have yet to explore weather vascular dysfunction in DCS is related to the eNOS uncoupling, this research carries on the preliminary discussion.[Method]Animal experimental were SD rats and them were randomly divided into 5 groups, blank control group (1):30 rats were placed in 0.3m3 pressure cabin,which used for small animalreproduction DCS, not processing compression, staying 65min, continuous aeration the air,maintaining the CO2 level is lower than 300ppm.The cabin humidity was maintained at 40%-60% and the temperature of 27-30 DEG C. Rats in the cabin can be freely and the behavior of rats can be recorded and observated by closed circuit television display system.(2) model group (DCS):as the control group 30 rats were put in the same cabin.The pressure and temperature, humidity are arranged in the same. With the speed of 100kpa/min compression, air pressure in the chamber increase to 600kpa (equivalent to 60msw) and mainten 60min.During the process the air was aerated continuously to maintain the level of CO2 lower than 300ppm.And at the same speed to unload to atmosphere. (3) low dose of YFHXG group:DCS model making+YFHXG (0.165g/kg).30 rats were fed on the dose of 0.165g/kg Yifei Huoxue granule, twice a day, continuous feeding for 1 weeks.Than the rats were proceed the same way of Simulated Submarine Escape. (4) middle dose of YFHXG group:DCS model making+YFHXG (0.33g/kg).30 rats were fed on the dose of 0.33g/kg Yifei Huoxue granule, twice a day, continuous feeding for 1 weeks.Than the rats were proceed the same way of Simulated Submarine Escape. (5) high dose of YFHXG groups:DCS model making+YFHXG (0.66g/kg).30 rats were fed on the dose of0.66g/kg Yifei Huoxue granule, twice a day, continuous feeding for 1 weeks.Than the rats were proceed the same way of Simulated Submarine Escape.The number of rats suffering from decompression sickness and death in each group were recorded. survival rats in each group were adopted blood in abdominal artery.Flow cytometry assay platelet activation in each group of rats, the level of 6-keto-PGF(1 alpha) and TXB2 in serum was detected by radioimmunoassay.The lung tissue and pulmonary artery tissue of survival rats was removed under anesthesia.Though lungimmunofluorescence staining to observate the platelet aggregation in lung and tissue factor expression in pulmonary arteries.Survival rats in the DCS group and control group were stripped pulmonary artery under anesthesia, the endothelium-dependent vasodilatory capacity of isolated pulmonary artery was detected, The level of nitric oxide synthase (eNOS) and its monomer were detected by Western blotting.Protein of nitro level is also tested by WB.Superoxide anion probe (DHE) staining was used to detect ROS formation of reactive oxygen species.[Result]In the part about platelet activation.There were no significant differences in mortality within groups(P>0.05) (mortality rate:16/30 with saline,15/30with 0.165 g/kg of YFHXG,10/30 with 0.33 g/kg of YFHXG, and 13/30with 0.66g/kg of YFHXG group) and DCS severity (neurological DCS incidence:5/30 with saline, 6/30 with0.165 g/kg of YFHXG,4/30 with0.33g/kg of YFHXG, and 5/300.66 g/kg of YFHXG group). Flow cytometry showed that C/DC could activate the platelet, while YFHXG inhibited platelet activation dose-dependently manners. Immunofluorescence showed that C/DC enhanced platelet aggregation in lung but had no influence on the concentration of(Von Willebrand Factor) vwf in pulmonary artery, and radioimmunoassays showed that C/DC significantly increased the ratio of TXB2/PGI2 in serum, while YFHXG decreased the aggregation of platelet in lung and attenuated the increase in the ratio of TXB2/PGI2.In the party of eNOS uncoupling.The endothelium dependent vasodilatation function of isolated pulmonary artery in DCS group has significantly impared. There were no significant differences in they level of eNOS between groups(P>0.05).Western Blog showed that unsafety decompression had uncoupled the eNOS and increased the ratio eNOS monomer/dimer significantly.The level of tyrosine nitration in pulmonary artry has increased significantly in DCS group.DHE showed that the unsafety decompression enhanced the concentration of ROS in pulmonary artery.[Conclusion]The research and conclusions of the experiment show unsafe decompression during the simulated submarine escape cause bubble formation in vasculars, resulting decompression disease. The bubbles can denunate The endothelium dependent vasodilatation function of isolated pulmonary artery and dissociate eNOS dimer into monomers, decreasing NO production, increasing the synthesis of ROS. A large number of platelet activation appeared in the DCS model rats, the TXB2/PGI2 ratio was increased in the lung tissue.the emergence of a large number of platelet aggregation in lung, but no change in expression of TF in pulmonary artery. At the same time, Yifei Huoxue granule could inhibit the platelet activation and pulmonary aggregation in DCS rats, and reduce the TXB2/PGI2 ratio.The following conclusions can be obtained from our study:(1) The rats after simulated submarine escape can appear dysfunction of the endothelium dependent vasodilatation.Its mechanism is associated with the eNOS uncoupling;(2) The eNOS uncoupling can lead to NO synthesis decreased, decreasing vasodilatory capacity.And it also can cause increasing in ROS synthesis, which can cause super oxidative damage in vascular tissue;(3) The rats after simulated submarine escape can leads to platelet activation by BIPA, with increasing in the rate of platelet activation and the level of platelet aggregation in lung;(4) Yifei Huoxue granule can inhibit platelet activation in a concentration dependent manner, considering Yifei Huoxue granule has the functions of promoting blood circulation;(5) Alough Yifei Huoxue granule can reduce platelet activation after unsafe decompression, morbidity and mortality have not reduced. Considering decompression sickness is related with damage in multi organization and multi system including nitrogen narcosis, barotrauma.The protective effect of Yifei Huoxue granule in decompression sickness is limited, it isn’t able to affect the overall morbidity and mortality. |
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