Animal model of diabetes melitus

Medicilon provides a variety of effective animal models according to customer needs to test the effectiveness of drugs. Conventional endocrine diseases and metabolic diseases include: diabetes, obesity, dyslipidemia, etc. Animal experiments are conducted with large mice and hamsters.

Endocrine and Metabolic Disease Model

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Animal model of diabetes

Animal models of diabetes are usually divided into two types: inducible and spontaneous.

There are also many ways to copy animal models of diabetes. In animal selection, mainly mammals, rodents are the most used and most widely used, mainly used for drug screening, pathological changes and other aspects of research. Rabbits are mainly used for diabetic hyperlipidemia. In recent years, minipigs have become interested. For example, Yucatan minipigs are gaining more and more attention because their digestive system organ functions are closer to humans, and they have a tendency to spontaneously diabetic. Sexual inheritance is dominant inheritance, which can produce micro blood in the fundus within 1 year of onset

Tube proliferation changes, etc.

1. animal model ofexperimental diabetes mellitusThe replication method of animal model of experimental diabetes mellitus mainly includes:

① Injection of hyperglycemia factors, such as growth hormone, glucagon, glucocorticoids and catecholamines, etc., this method can replicate some secondary diabetes models.

②Injecting chemicals can cause damage to islet B cells, such as streptozotocin (STZ), alloxan (Aloxan), and diphenylthiocarbbazine (Diphenylthiocarbbazine) can cause irreversible damage to islet B cells. Cyproheptadine, aspartase, 6-aminonikamide (6 aminonicotinamide), 2 deoxyglucose, mannoheptulose, etc. can cause reversible damage to B cells. The most used chemical substance is imported streptozotocin, which is injected intraperitoneally or intravenously from 30mg/kg to 100mg/kg. After a few days, it can cause permanent hyperglycemia in animals such as dogs or rats, but STZ causes diabetes. At the same time, it can also cause cataracts and coronary atherosclerotic plaques. The domestically produced alloxan also causes hyperglycemia with only one injection, but at the same time causes damage to liver and kidney tissues, which is physiologically very different from that of human diabetes. Give cyproheptadine to rats for 4 weeks, which can produce symptoms of hyperglycemia, islet B cell secretion gradually disappears, insulin secretion is normal at rest, when glucose load is given, it can not cause insulin phase II secretion, stop After 1 week of medication, the lesion can automatically return to normal.

③Injected organisms and organisms

The product causes B cell destruction, such as the M-type mutation of mouse encephalitis virus and myocarditis virus can induce diabetes in several strains of adult mice. Interleukin-1 has a selective cytotoxic effect on B cells within a certain dose and range. Mediated fine

Cytotoxic effects can lead to IDDM.

④ Surgical removal of most or all of the pancreas, and giving a high-sugar diet stimulation, causing secondary permanent diabetes. The following describes two commonly used copy methods:

(1) Alloxan-induced diabetes model in rats: Alloxan can selectively act on pancreatic B cells of many species of animals, causing irreversible necrosis of B cells, while A cells, D cells and exocrine tissues are not damaged, resulting in Animal diabetes. First, tetraoxopyrimidine was freshly prepared into 1% to 3% solution with water for injection or physiological saline. The experimental rats were kept in a metabolic cage for 1 week, and the body weight, drinking water, urine volume, and random blood glucose were recorded. Alloxan 3Omg/kg body weight ~ 40mg/kg body weight, one injection into the tail vein or sublingual vein, the blood glucose value of rats can change in 3 time limits after injection, the initial hyperglycemia phase is about 2 to 4 hours after injection, about 6 Hypoglycemia occurs around hours, and symptoms of persistent hyperglycemia accompanied by polydipsia and polyuria appear after 18 hours, and then blood glucose reaches 16.7 mmol/L or more, which can be used as a successful model after 2 weeks of stability. Or a freshly prepared solution of alloxan is injected intraperitoneally at 120-150 mg/kg body weight, and the blood glucose level will increase after 24 hours. ≥16.7mmol/L can be used for more than 2 weeks. The pathophysiology of this model is similar to that of human IDDM, and most of them are in a permanent high glucose state, but some animals can naturally relieve within 3 weeks. The sensitivity of different species of animals to alloxan varies greatly, and factors such as feed and nutritional status will affect the incidence of diabetes in animals. If a continuous injection of 120mg/kg body weight is used for two days, the mold formation rate can reach 100%. All four units of pyrimidine can be synthesized by themselves in many domestic units.The drug is cheap, the dosage is small, the method is simple, the blood glucose response is sensitive, and high blood sugar is formed Fast, the model is stable, and the mortality rate is low. It can be used in the research of human IDDM. When using this model, it is necessary to know that alloxan has a certain toxic effect on animal liver and kidney.

(2) Streptozotocin-induced diabetes model in rats: streptozotocin can cause massive necrosis of pancreatic islet B cells in animal Wistar rats.By adopting different administration methods, an animal model and NIDDM-like animal model can be copied. Animal model of late-onset IDDM.

1) Instant haircut: Give a sufficient amount of streptozotocin to animal Wistar rats at one time, causing a large amount of damage to B cells, reduced insulin synthesis and secretion, causing disturbance of glucose metabolism, leading to diabetes. STZ was freshly prepared into a 2% solution with 0.1mol/L sterile sodium citrate buffer, the pH was adjusted to 4.5, and the bacteria was filtered and sterilized. Rats were fasted for 10 hours, and the SIZ solution was injected into the abdominal cavity or tail vein at a time of 50mg/kg ~ 65mg/kg body weight. The blood glucose was greater than or equal to 16.7mmol/L within 24 hours. Stable for 5 days can be used as a successful model.

2) Late onset: According to the characteristics of Freund’s complete adjuvant (CFA) that can stimulate the body’s immune function, the combined use of small doses of SIZ and CFA can activate lymphocytes in rats and induce slight changes in islet B cells. The activated T lymphocytes with cytotoxicity can attack the slightly degenerated cells as target cells, which leads to the occurrence of autoimmune processes, which further aggravates the damage of membrane B cells and causes diabetes. The preparation of streptozotocin is the same as that of Freund’s adjuvant. Weigh the liquid paraffin and lanolin at 4:1, grind and mix it, and divide it into packages.After autoclaving, store it at low temperature. Add 1.5 mg/0.5 mL before use. Bacteria inactivated BCG vaccine, used after sterile emulsification. Rats were fed with normal water, and 0.5 mL CFA was injected intraperitoneally on the first day, and S1Z solution was injected intraperitoneally at 25 mg/kg body weight the next day. Once a week, repeat the above steps for 3 consecutive weeks, some rats can be modeled in the second week, and the modeling rate can reach 87.5% in the third week. The instant hairstyle model is more suitable for the related research of NIDDM. Usually a single dose of 50 mg/kg body weight does not show natural relief. From the 6th to the 27th day, the islets are regenerated to a certain extent, and the function is partially restored, but they have not reached normal and are still in a state of hyperglycemia.

Late-onset STZ animal models have immunological changes, which are closer to the occurrence and development of human IDDM. There are reports of anti-islet cell antibodies in rats. The effect of streptozotocin on diabetes is hardly affected by feed composition and nutritional status. STZ can also cause diabetes in guinea pigs that are resistant to the effect of alloxan-induced diabetes. The price of STZ is more expensive, but the effect of causing diabetes is very stable and easy to use.

2. Spontaneous diabetes model (animaI model of spontaneous diabetes melitus)

 Inherited and spontaneous diabetes animal models are closer to the natural onset and development of human diabetes, and are particularly suitable for studying the etiology of diabetes. Such as “BB” Wistar rats, NSY diabetic mice, NH obese diabetic rats, KK diabetes mice and so on. Several models are introduced below:

(1) Spontaneously diabetic BB Wistar rat model: A group of outbred spontaneously diabetic Wistz rats were reported in 1977 by the Ottawa Biological Cultivation (BB) Laboratory in Canada, which is an ideal animal model of IDDM. In 1990, Shanghai introduced the pure line BB mice for the first time, and randomly matched the parent breeders and bred the offspring BB mice to prepare the spontaneous hereditary IDDM animal model. The incidence of offspring BB rats can reach 90%. The clinical onset is sudden and often without warning. The age of onset is 58 to 123 days of age. All rats with fasting blood glucose of 1Omol/L and urine glucose ++ can be diagnosed. Weight loss, hyperglycemia, diabetes, polyuria and insulin deficiency, most require insulin treatment. The pathogenesis of B cell damage in BB rats may be related to cell-mediated autoimmunity. This model can be used to study the genetic factors, environmental factors and immunological factors of IDDM. Chronic complications related to diabetes have not been fully determined in this strain of rats. Studies have found that cardiac microvascular lesions can be observed 21 weeks after successful replication of the model. In order to avoid death during feeding, daily administration of PZI 2μL/piece～4Ml/piece, or Deltamica 3Omg/piece～40mg/piece.

(2) Spontaneously diabetic NSY mouse model: NSY mice are closely related strains of spontaneously diabetic mice, which are selected and reproduced from JCL:ICR mouse inbred strains according to glucose tolerance. It is characterized by age-dependent spontaneous diabetes. The cause of diabetes in NSY mice may be the abnormality of pancreatic B cells’ glucose-stimulated insulin secretion function. The incidence of cumulative diabetes in male mice at week 48 is 98%, and Female mice are only 31%. No obvious obesity occurs at any age. At 24 weeks, significant glucose-stimulated insulin secretion function can be reduced. No abnormal morphology of the pancreas is observed. It has the characteristics of fasting hyperinsulinemia. This model is helpful for humans NIDDM genetic predisposition and disease

The study of rational occurrence is especially suitable for studying the role of insulin resistance in the pathogenesis of NIDDM.

(3) Spontaneous non-obese diabetic GK rat model: It is a kind of original breed reproduced from normal Wistar germline rats by Goto and kakisaki of France in 1988 after several generations of selective breeding and supplemented with glucose tolerance as indicators Non-obese NIDDM rats. Animals with hyperglycemia and impaired glucose tolerance can be obtained from the 1st to 4th generation of the sub-lineage. Males and females have the same morbidity. Diabetes persists after week 32, pancreatic insulin storage is reduced by 50%, and the number of B cells is reduced. , B cells lack response to high glucose stimulation. It is suitable for the related research of human NIDDM.

(4) Chinese hamster model of spontaneous genetic diabetes: In 1985, a large group of Chinese hamsters were successfully cultivated by Shanxi Medical College, and a model of spontaneous hereditary diabetes was established. The incidence of diabetes is about 25%. After inbreeding from 2 to 6 generations, especially after mating with siblings, the incidence can reach 90%. Females are more than males. The incidence of diabetes is still high in young rats under high calorie fat and excessive diet. Can be increased. The animals in this model are mostly non-obese, with moderately and slightly elevated blood glucose levels, and the serum insulin concentration is diverse, most are normal, a few are elevated or decreased, and the degree of islet lesions varies, because the kidney sugar threshold of Chinese hamsters is lower than that of humans It is too high, and the difference between individuals is also large. The urine glucose measurement value is significantly less than the blood glucose measurement value. The incidence of diabetes is affected by non-genetic factors such as dietary environment. It has multi-gene genetic characteristics and is very similar to human NIDDM, so it is optional. Ideal model for NIDDM research. (2) Animal model of thyroid disease (animal model of thyroid disease) replication method

There are many types of thyroid diseases, the causes of various types of thyroid diseases are different, and most are related to genetic factors. The most common autoimmune thyroid disease belongs to multigene inheritance. Since 1970, foreign scholars have successfully bred chickens and dogs with spontaneous hereditary autoimmune thyroiditis. Some have also injected mouse thyroid globulin into rats to replicate the rat autoimmune thyroiditis model. However, the current animal models of thyroid disease are still mainly established by exogenous administration of thyroid hormones and antithyroid drugs.

The methods of establishing animal models of goiter and hypofunction are more mature, and the following methods can be used according to the research purpose:

① Use the food in the local goiter disease area and formulate feeds to feed the animals according to the dietary habits of local residents, resulting in iodine deficiency.

② Application of antithyroid drugs (such as propylthiouracil, methylthiouracil, and tabazole) to inhibit thyroid follicular cell uptake of iodine and iodine utilization, and inhibit the synthesis of thyroid hormones.

③ Surgical removal of most or all of the thyroid gland.

④ Use 131I to destroy thyroid follicular cells.

⑤ Breed spontaneous hereditary autoimmune thyroiditis. Animal models that induce hyperthyroidism are usually taken orally or by injection of T3 or T4.

1. Rat model of iodine-deficient goiter and hypothyroidism Taking advantage of the low iodine concentration of food in endemic thyroid disease areas, feeding Wistar rats causes iodine deficiency, causing goiter and hypothyroidism. The specific method is to prepare the feed according to the local residents’ dietary habits with the food of the ward, including wheat 30%, corn 60%, sweet potato dry powder 10%, the feed contains iodine content of 0.043mg/kg, select 50g-100g Wistar rats to feed with the above feed, After drinking distilled water, goiter may appear after 3 months, the concentration of TT4 and FT4 in the blood will decrease, and the level of TT3, FT3 and TSH will increase, and a successful rat model of iodine-deficient goiter and hypothyroidism can be obtained. This method has certain requirements for experimental conditions. It is best to conduct experiments in local goiter epidemic areas. In the coastal areas, the air has high iodine content, which is easy to enter the animal body and is not easy to succeed. Air filtration is best. This model is suitable for various studies of human endemic goiter.

2. Induced goiter rat model Using the drug propylthiouracil, which inhibits thyroid iodine uptake and thyroxine synthesis, reduces thyroid hormone synthesis and raises blood TSH levels, causing experimental goiter. Choose weight

Rats of 100～200g, dissolve propylthiouracil (PTU) with normal saline, and intraperitoneally inject PTU (Sigma product) 1mg/1 00g body weight for 4 weeks, there is an increase in thyroid weight, blood TT3, FT4 levels are reduced, while TT3 and FT3 levels are increased, which can be used to study changes in function and metabolism in hypothyroidism.

3. Induced hyperthyroidism in the rat model Exogenous administration of thyroid hormone (T4) or tripyrathyronine (T3) can cause a series of metabolic changes in rats with hyperthyroidism. Select adult rats weighing 100g～250g, dissolve L－T3

In normal saline, L-T350μg/100g body weight was injected intraperitoneally every day for 7 consecutive days. Or dissolve T4 in normal saline, inject intraperitoneally 250μg/100g body weight every day, continuous injection for 18 days or drink 0.0012% T4 aqueous solution every day for 18 days, there may be increased blood T3 and T4 levels, TSH decreases, and thyroid weight decreases . This model can be used for clinical and therapeutic studies of hyperthyroidism, but it is of little help for the study of etiology and pathogenesis.

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Animal model of diabetes melitus