【Animal Modeling】-Research on Animal Model of Renal Vascular Hypertension

  1. Overview of Renal Vascular Hypertension

  Renal vascular hypertension is hypertension caused by renal ischemia caused by stenosis or obstruction of the main trunk or branches of the renal arteries on one or both sides, and is the most common secondary hypertension. my country's renovascular hypertension accounts for 2% to 7% of the hypertensive population.

  "Renovascular hypertension is caused by the activation of the renin-angiotensin-aldosterone system due to ischemia, and the activation of the renin-angiotensin-aldosterone system has been recognized in the pathogenesis of hypertension. Therefore, animal renal artery stenosis can replicate the hypertension model very similarly. In 1934, Goldblatt proved that stenosis of canine renal artery can produce persistent hypertension, which opened up a way for experimental research on hypertension. The renovascular hypertensive rat animal model is easy to replicate and has sufficient animal sources. It is a commonly used animal model for the study of hypertension mechanism and drug experiment.

  2. Preparation of animal model of renal artery stenosis

  Currently. Rat models of renovascular hypertension can be divided into: ①two kidneys and one clip renovascular hypertension rat model; ②single kidney single clip renovascular hypertension rat model; ③double kidneys and double kidneys folder. Rat model of renal vascular hypertension.

  (one) two (double) kidney one clip type renovascular hypertension rat model

  1. Methods Healthy male SD rats weighing 180-220g were anesthetized with sodium pentobarbital. The back was fixed on a wooden board and the abdomen was exposed. A midline incision was made into the abdominal cavity. One renal artery was separated and exposed. A silver clip or silver ring with an inner diameter of 0.2 mm was used. Sleeve on the renal artery causes renal artery stenosis. If the postoperative systolic blood pressure is higher than 140mmHg, it is determined that the two-kidney one-clip renovascular hypertension animal model is established successfully.

  2. It is evaluated that this model has the advantages of simple modeling, high success rate, and strong identity, and is comparable to the pathological process of human hypertension. It is the most commonly used classical animal model of hypertension in the world. It is currently the best choice for screening antihypertensive drugs. One more model.

  (2) Double kidney double clamp type renovascular hypertension rat model Because the incidence of spontaneous stroke can reach 56.4%, it is also called stroke-prone renovascular hypertension rat model.

  1. Methods Healthy male SD rats weighing 120-240g were selected and anesthetized by intraperitoneal injection of 3% pentobarbital sodium for 10-15 minutes. Under aseptic operation, the bilateral renal arteries were bluntly separated through a median longitudinal incision in the abdomen. , Use the self-made ring silver clip with inner diameter of 0.2mm to clamp the initial part of the bilateral renal arteries respectively. The entire operation does not damage the kidneys, liver, chylous cistern. Renal veins. A small amount of penicillin was injected intraperitoneally after the operation to prevent infection. The blood pressure of male SD rats before the experiment was (110±9) mmHg, which rose to (124.5±11.2) mmHg one week after the operation, which was significantly higher than the preoperative blood pressure level. The blood pressure exceeded 150.0 mmHg at 3 weeks after the operation, and some rats had blood pressure. Can be higher than 250mmHg.

  2. It is evaluated that this model is the first hypertensive rat model in my country, and it is currently being promoted in China. It is a promising and ideal hypertensive animal model, which can be widely used in complications such as heart, brain and kidney of hypertension. Research on prevention and treatment. For example, using renal vascular hypertension rats to establish a cerebral aneurysm model to explore the mechanism of aneurysm; to establish an artificial cold wave environment to explore the relationship between artificial cold wave and stroke, this model can also be used.

  (3) Single kidney single clamp renal vascular hypertension rat model

  1. Methods Take male SD rats weighing 150~240g, anesthetized with sodium pentobarbital, excise the right kidney outside the peritoneum, separate the left renal artery, and narrow the left renal artery to 1/3 of the original diameter with a silver clip. The arterial systolic blood pressure gradually increased, reaching a peak (average 165mmHg) in the 8th week, and the blood pressure remained at a high level without any significant increase.

  2. Evaluation Due to the low success rate of this model, the blood pressure cannot continue to rise, which limits its scope of use, so it has been seldom used at present.

  3. The purpose of model establishment

  Animal model is a useful tool for scientific research. It can approximate the occurrence and development of human diseases, and can simplify experimental conditions and avoid the limitations of human experiments. The establishment of a stable, practical, reproducible and clinically close animal model of renal hypertension is of great significance for the further study of the pathogenesis and treatment of renal hypertension. There are many methods to establish animal models of hypertension. Renal artery stenosis methods have the following characteristics: ①The principle of modeling is similar to the pathogenesis of clinical secondary hypertension patients, that is, stenosis of renal arteries can cause renal ischemia, leading to kidney ischemia. Renin is formed, which in turn increases the blood angiotensin content and raises blood pressure; ②The model is simple and the operation success rate is high. The success rate of the two kidney one clip type is 95%; ③The experimental cost is higher than that of spontaneously hypertensive rats Low, suitable for the experimental needs of a large number of samples and a large amount of animals; ④After the renal vascular model surgery, the blood pressure of the rats gradually increased after 4 weeks, and stable hypertension was formed and maintained for a long time. The renovascular hypertension model is widely used in the study of human hypertension and its complications due to its simplicity and reliability. It is also a model that is currently used in the study of antihypertensive drugs.

  4. Solve scientific problems in experiments

  The peak blood pressure of rats with renovascular hypertension is high and stable. With the extension of the observation time, the blood pressure level continues to rise steadily, which is basically the same as the blood pressure evolution process of human hypertension. The target organ damage caused by renovascular hypertension is very close to the pathological changes of human hypertension.

  1. Vascular changes Small arteries have varying degrees of degeneration, fibrinoid necrosis, arterial wall hyperplasia, which causes wall thickening, luminal stenosis, and some microaneurysms; it is very similar to human hypertensive vascular changes.

  2. Renovascular hypertensive rats were fed with ordinary food alone, and 61.8% of the rats had spontaneous stroke 40 weeks after the double kidney and double clamp operation. Among them, the major ischemic stroke (42.9%) and the hemorrhagic stroke accounted for 22.6%. On the basis of extensive coronary atherosclerosis and left ventricular hypertrophy, 41.8% of the rats had myocardial infarction, while the spontaneous stroke rate was less than 30% when the spontaneously hypertensive rats were fed ordinary diet; When potassium and high sodium feed are used, the spontaneous stroke rate can reach more than 80%. Therefore, renovascular disease has the advantages of no special feeding, high stroke incidence, and no genetic limitations. Renovascular hypertensive rats are used to study stroke And hypertensive heart damage is closer to the clinical: greater reliability.

  3. Renal artery stenosis exempts the kidney from the effects of high blood pressure, so the kidney has no serious function and structural damage, and the rat is not acute. Renal failure and death can cause obvious damage to the small arteries of the heart and brain similar to rat hypertension.

  Taking advantage of the pathological changes of renal vascular resembling human hypertension, Huang Ruxun and others have successfully established a large number of stroke models that are close to the pathophysiological process of human stroke. Among them, the spontaneous stroke model in the natural environment realistically simulates the onset of human stroke. Process and physiological mechanism: The spontaneous stroke model induced by climatic factors simulates and reveals the clinical phenomenon of high incidence of stroke caused by sudden temperature changes; the model of spontaneous stroke induced by various drugs is of great help Explore the blood pressure regulation of stroke and the rationality of clinical medication. Electrocoagulation, ligation, thread plug and photochemical cerebral infarction models are close to the clinical pathological process of human hypertensive stroke. On this basis, the research on the pathophysiological mechanism of hypertensive stroke and the exploration of treatment options have good results Clinical Value.

  5. Progress in research on renal artery stenosis

  The modeling method of renal hypertension originated from the classic experiment of Goldblatt et al. in 1934. The specific method is to firstly close the left renal artery for 4 hours to cause an acute increase in blood pressure in the rat, and then open the blood vessel to release the accumulated renin into the circulation. In the blood, the formation of AngⅡ is catalyzed, leading to an acute increase in blood pressure.

  Some scholars used the Collins method to perform renal artery stenosis, using 420 chrome catgut to make a figure-eight ligation around the renal artery 0.5 to 1 cm from the beginning of the renal artery. Unilateral renal artery insufficiency in 18 dogs was ligated to form persistence. Renal artery stenosis hypertension. After observation, it was found that its pathological changes were similar to clinical renal artery stenosis hypertension caused by dysplasia of the medial and adventitia fibromuscular. According to experimental experience, it is advisable to control the tightness of the ligature when the renal artery is ligated after the arterial spasm disappears after the stenosis and no renal ischemia is seen. The electromagnetic flowmeter monitors the renal blood flow to reduce by about 30%. Experiments have also confirmed that unilateral renal artery stenosis can also form persistent hypertension while retaining the contralateral renal artery.

  Yang Ning et al. investigated the effect of unilateral renal artery cannula ligation to establish an animal model of renovascular hypertension. The results showed that the unilateral renal artery cannula ligation method can successfully establish an animal model of renovascular hypertension. The animal model can simulate the hypertensive lesions caused by unilateral renal artery stenosis in humans. The method is simple, reproducible and has a high success rate. Some scholars used a self-made 0.30mm internal diameter silver clamp to clamp the left renal artery in rats, which caused the effect of constriction of the left renal artery, resulting in a model of renal vascular hypertension: there are also ordinary U-shaped silver clamps commonly used in neurosurgery. The rat renal artery was clamped, and a double-kidney-double-clamp renal vascular hypertension model was successfully made.

  Fu Jihua et al. replaced the U-shaped silver clip with a small circular ring made of aluminum cans to create a rat model of renovascular hypertension. The characteristics of this method are that the diameter of the small ring is easy to control and the preparation is simple, and because the metal ring does not stretch Sex, so after stenosis of the renal artery, Ting obtains more constant. The blood flow of the renal artery. After the operation, the animal's hypertension is both high and stable, and the operation success rate is high. This method overcomes the shortcomings that the U-shaped silver clip is not easy to make and its size is not easy to control to a certain extent. Zeng Jinsheng et al. used silver clamps with an inner diameter of 0.3mm to clamp bilateral renal arteries to replicate a stroke-prone renovascular hypertension rat model. The hypertension is 100%, and the peak blood pressure is high and stable at the level of 175~200mmHg. , And damage to cerebral arteries similar to human hypertension occurs. When fed with ordinary feed, 56.4% of the rats had spontaneous strokes of various types within 40 weeks. All rats had varying degrees of ventricular hypertrophy and intramyocardial small coronary artery disease. 41.8% of rats had spontaneous myocardial infarction. The cardiovascular damage of this model is basically the same as that of human hypertension. It is used to study the mechanism of hypertensive encephalopathy and hypertensive heart disease and verify the prevention and treatment effects of various drugs. The obtained research results are closer to clinical reality. They also compared this rat with a stroke-prone spontaneous hypertensive rat. The model has the advantages of convenient feeding, no need for specific rat controls, and a wide range of applications. Huang Ruxun et al. used male SD rats to clamp both renal arteries with an inner diameter of 0.30mm circular silver clamps to replicate the renal vascular hypertension model, and compared the effects of different silver clamps and different clamping methods. Results The formation rate of renal vascular hypertension replicated by the double-kidney double-clip method using the ring-shaped silver clip reached 100%, and the blood pressure was stable at (200±24) mmHg. With the extension of the observation time, the blood pressure level rose steadily, which was similar to human hypertension The pathological process was basically the same, and it was successfully replicated to simulate clinical pathology. A series of studies have been carried out on the rat model of renovascular hypertension. Wang Liwen and others performed a straight left incision to narrow the renal artery retroperitoneally, and the survival rate reached 100% after success. A healthy 3-month-old Wistar rat weighing 180-220g was used to make an incision between the kidney and the spine in a direction parallel to the spine, with an incision of 1.5-2cm. The blood pressure can continue to rise after reaching the hypertension standard 2 weeks after the operation, and reach a peak around 4 weeks and remain at a stable level. In contrast, the traditional midline abdominal incision is 3 to 4 cm long, and the abdominal viscera such as gastrointestinal viscera must be turned over to expose the posterior peritoneum. The posterior peritoneum can be destroyed to expose the renal artery, which may cause abdominal infection due to large trauma; After the kidney is exposed, the renal artery is separated from the renal pedicle retrogradely, which is easy to cause the renal pedicle traction, and the arteries and veins at the renal hilum are covered by the same vascular sheath, which is difficult to dissect. However, the left straight incision is not inserted into the abdomen, and the incision is small. And compared with the right side, the anatomical relationship is simpler, so it is easier and safer to choose the left straight incision, and it is worth promoting. Yin Shihua et al. used silk thread constriction instead of silver clips, and directly used No. 1 silk thread on the left kidney to narrow the renal artery to form renal hypertension. The distance from the incision to the midline D (cm) = (rat weight × 0.005) ± 0.01: the outer diameter of the silver wire (mm) = (rat weight / 1000) ± 0.02, the weight of the rat is preferably 180-220g. Using this method to make experimental models of renovascular hypertension rats is simple and easy to implement, the experimental cost is low, and the success rate is high (83%). After the model is successful, the systolic blood pressure increases significantly after two weeks, and it is accompanied by four weeks after the operation. The formation of left ventricular hypertrophy is an ideal experimental animal model for basic and clinical medical researchers to study hypertension and myocardial hypertrophy caused by hypertension.

  6. Evaluation characteristics of antihypertensive drugs in experimental models

  This animal model has the characteristics of high hypertension formation rate and high survival rate, and the blood pressure is stable after reaching the peak, and the fluctuation is small. It can create good conditions for a variety of blood pressure and blood pressure experiments, and the test drug for this type of hypertension The antihypertensive effect is generally consistent with the curative effect of clinical hypertensive patients. It is suitable for the study of antihypertensive drugs and is widely used in medical experiments.