麻醉药物,皮肤微循环 z-bo 2020-09-22 366

　　Background: Microcirculation is the last link between the cardiovascular system and the cellular level. Many studies have investigated the effects of anesthetics on the human peripheral and systemic microcirculation, especially on microvascular perfusion to ensure proper tissue oxygenation and Nutrition supply. Due to its simple operation, complete anesthesia behavior, steady-state response after anesthesia, and clear genetic background, mice are an ideal model for studying anesthetic response. Breeding mouse strains are widely used in pharmacology and toxicology research, while CD1 mice are used in anesthesiology research. We hypothesize that the most interesting feature is polygenic inheritance, which is related to the phenotypic variation of genetically heterogeneous populations. In addition, the mouse microcirculation perfusion model used for in vivo research requires the use of anesthetics, and the conversion of different anesthetics in the research will interfere with the experimental results. In addition, in preclinical trials of peripheral vascular diseases, pentopental sodium and midazolam isoflurane were used to evaluate the therapeutic effect of angiogenesis. The most popular inhalation anesthetics (halotan, isoflurane) or injection anesthetics (propofentanyl, barbiturates, ketamine) used for microcirculation reactions are used in invasive or reverse microcirculation biomicroscopy . Microcirculation study of suspended muscles and back muscles. So far, there are almost no data reports on the capillary action of commonly used laboratory animal anesthetics acepromazine and dexmedetomidine. Acepromazine maleate is an α-adrenergic receptor antagonist, widely used for sedation and anesthesia of experimental animals. The combination of acepromazine and isoflurane can reduce the need for isoflurane, but it can increase peripheral vasodilation and lower blood pressure in dogs. The combination of acepromazine-ketamine-xylazine is the safest and most reliable surgical anesthetic recommended for mouse surgery, but it is accompanied by severe hypotension. Dexmedetomidine hydrochloride is a selective α2-adrenergic receptor agonist with selective affinity for α2A and α2B receptors. Dexmedetomidine hydrochloride is used in humans and animals during the perioperative period Can reduce abnormalities. The required doses of halotan, thiopental sodium and propofol can reduce the excitement of the sympathetic nervous system during surgery and prevent hemodynamic events (such as acute kidney disease). Reliable blood perfusion technology that can measure tissue can greatly improve the understanding of microvascular conditions under anesthesia. Laser Doppler Perfusion Imaging (LDPI) is a non-invasive technique that can acquire two-dimensional color images of skin perfusion in real time and quantitatively. The increased measurement area can better evaluate the heterogeneity of blood flow, and can determine the subtle changes in skin perfusion capillaries after induction of anesthesia, thereby suggesting the microcirculation conditions in other places. LDPI provides a simple and accurate estimation of peripheral blood perfusion, but the method to study the microcirculation changes in mice related to anesthesia is still blank. In this study, laser Doppler perfusion imaging evaluated the effects of anesthetics on mice by examining several biological variables (such as gender, environmental variables, and operational variables, such as animal temperature, skin area, and recording conditions). The cyclical effect of technical operating procedures has been formulated. Our LDPI technology is a potentially valuable research tool for measuring real-time microcirculation changes in vivo in preclinical mouse experiments. Results: Figure 1 shows the animal position and the operating standards for post-processing and measurement of LDPI imaging. Table 1 shows the value of microvascular perfusion. Average, minimum and maximum. There was no significant difference in the peripheral blood flow between men and women at each time point (P\→0.05). For the effect of different anesthetics on the peripheral blood of each group of animals, please refer to Figure 2. After maintaining anesthesia for 10-20 minutes, the average perfusion under isoflurane anesthesia showed an increasing trend in all mice (4.25-4.55V) , To reach a stable perfusion value, but in each group and the subsequent time. unimportant. Difference (P = 0.1). In contrast, the average LDPI values were significantly different between group 1 (acepromazine) and dexmedetomidine (group 2). After using acepromazine for 10-20 minutes, a significant increase in the perfusion value from 4.55-4.85 V can be observed. The use of dexmedetomidine can produce an important two-phase effect. After 5 minutes (2.47V) to 15 minutes (4.32V), blood perfusion increases significantly. The final blood perfusion level was close to isoflurane anesthesia, grouping and continuing until antagonized by atamizole. In the control mice, the peripheral blood perfusion did not change significantly until 30 minutes after 1.5% isoflurane anesthesia.

　　Discussion: Anesthetics regulate the microcirculation of vascular smooth muscle through the autonomic and parasympathetic nerves. Phenothiazine sedatives and αβ2 receptor agonists mainly exert hemodynamic effects by interacting with α adrenergic receptors, while phenothiazine drugs mainly cause vasodilation by blocking α1 receptors. It not only antagonizes the body, but also dopamine receptors. D1 dopamine receptors induce vasodilation, while D2 dopamine receptors are usually found in postganglionic sympathetic neurons. Dexmedetomidin is a selective α2-adrenergic receptor agonist. After excitement, it will cause a decrease in norepinephrine neurosecretion and cause a passive decrease in vascular resistance and heart rate α2A and α2B receptors, so it has a significant dose effect The affinity between the relationship and the body is preferred. Causes a two-way blood pressure response: short-term hypertension mediated by α2B receptors, and then hypotension mediated by α2A receptors. Phenothiazine drugs and α2 receptor agonists have different effects on peripheral hemodynamics. Acepromazine causes significant hypotension in anesthetized isoflurane, dexmedetomidine increases peripheral vascular tone, inhibits isoflurane, and Alcan induces vasodilation and reduces arterial blood pressure. LDPI allows non-invasive real-time use of two-dimensional color images to measure blood flow in perfused skin vessels. According to reports, laser Doppler perfusion technology can detect human sympathetic nerves under general anesthesia. The use of LDPI detection method in the microvascular perfusion mouse model has the advantages of simplicity and speed. In addition, different anesthetics can cause different changes in the blood flow of rodents. Therefore, the method of anesthesia used in the mouse microcirculation model should be considered and should not affect the blood vessels examined. The main finding of this study is that the LDPI device can evaluate the changes in the peripheral microcirculation of mice induced by anesthetics in real time. Although the analytical methods are different, the hemodynamic effects recorded under various anesthesia collaborations are the same as expected in preclinical and animal experiments. We chose to investigate the reference perfusion value recording under 1.5% isoflurane anesthesia, because the instrument scan is not hindered by exercise or single or combined sedatives. Isoflurane has little effect on the hemodynamic status of mice. Costantinides and others. Reported that the observed animal model animals were compared with 1.5% isoflurane to produce stable body temperature, mean arterial pressure (MAP) and heart rate (HR) values. Therefore, it is recommended to conduct physiological and pharmacological studies of cardiac function on a non-invasive imaging platform. In this study, isoflurane anesthesia has a reproducible and stable effect on peripheral blood perfusion. Lemke et al. It is reported that acepromazine can increase the blood perfusion of isoflurane soles, and reduce vascular tone and arterial pressure. With dexmedetomidine, the plantar blood perfusion decreases rapidly and dramatically, and then the long-term perfusion increases, providing the typical two-phase hemodynamic effects of this sedative. In all mice, the increase in perfusion of dexmedetomidine after 15 minutes did not exceed the perfusion value provided by isoflurane. It is significantly lower than the perfusion value of acepromazine. Even after using Atimezol injection, the perfusion level did not increase significantly. Pay attention to operation and avoid method deviation. So far, the skin has been used as a microcirculation model to explore the vascular mechanism of cardiovascular, kidney disease or diabetes. Autonomic innervation of capillaries in this area, somatic stimulation of sympathetic nerve activity of skin arteries, location and body temperature are all important factors that affect skin blood flow meters. Noradrenergic sympathetic vasoconstrictor can irritate areas of hairless skin. In some strains, it is regulated by alpha adrenergic receptors. For these reasons, we chose the only area to study the changes in blood flow due to anesthetics, and also avoided the shearing effect. This operation will affect the skin arterial sympathetic nerve activity and may change the LDPI measurement value. In our setup, the precise positioning of the rear sole surface is very symmetrical and is precisely perpendicular to the laser beam to ensure data reliability. In addition, by monitoring and adjusting the infrared rectal probe, the body temperature can be maintained at 35.5 to 36.5°C. Our experiment was conducted in a temperature-controlled room, and the LDPI value of each animal after breeding was recorded. The effect of sex hormones on vascular tone remains a controversial issue. Stucker etc. The report said that in LDPI studies, men’s perfusion levels are often higher than women’s, and pointed out that the research group should consider gender tolerance differences when performing skin perfusion. Similarly, Kunkeletal. It was found that the skin perfusion of the feet of normal subjects was independent of gender. In our experiment, there was no significant difference in peripheral blood flow between men and women between the control group and the treatment group. According to the technical specifications of the equipment, indoor lighting should be kept at a minimum brightness. The threshold of the difference between the lighting background and the field measurement is set to 6.2V, and the adjusted scattered light intensity is 7-9V, which is the best data quality. The acquisition process uses a user-defined color table to compare 0-5V perfusion imaging (calibrate 0V perfusion output value to 0% perfusion and 5V perfusion output value to 100%). will). The average perfusion rate of each area on the sole surface has been standardized, thereby reducing the associated unavoidable anatomical and positional deviations. In order to further reduce the difference in data, the average value of 2 feet per foot was calculated as the perfusion value of each animal's hind limbs at each time point.