疾病动物模型,青光眼疾病 z-bio 2021-03-12 693

　　Glaucoma is a group of diseases characterized by suppression of optic nerve atrophy and visual field defects. Increased intraocular pressure is currently considered to be the main risk factor for glaucoma. Clinically, reducing intraocular pressure is used as the main treatment for glaucoma. Research on the etiology and treatment of glaucoma is progressing slowly, one of the main reasons is the lack of ideal animal models. Therefore, it is very important to establish an animal model of retinal ganglion cells and optic nerve damage that can simulate human glaucoma.

　　[Modeling mechanism] Using various methods to disrupt the return path of aqueous humor can increase intraocular pressure, and cause optic nerve degeneration, apoptosis and loss of optic ganglion cells. The most commonly used methods today are: (1) Injecting a suspension of small particles or viscous fluid into the anterior chamber will block the humor return path of the trabecular tissue. ②Electrocoagulate at least 3 groups of veins on the sclera surface and surrounding blood vessels of the extremities. Causes the eye's blood pressure to rise; ③Laser degeneration of trabecular tissue, prevents the backflow of aqueous humor and increases intraocular pressure.

　　[How to build a model]

　　1. Mice are 6-10 weeks old. Intraperitoneal injection is used for general anesthesia, while local ocular surface anesthesia is added to mice. Suspend polystyrene microspheres (φ10μm) in PBS so that the final concentration is 7.2×1000000 microspheres per milliliter of suspension. Approximately 2 μl of microspheres were injected in advance. On the 23rd day after the injection, the injection was repeated in one eye cavity. After each injection, use a slit lamp to observe whether the anterior chamber and iris are unobstructed, and whether there is corneal edema and penetration. After the first injection, the intraocular pressure of the mice was measured with a tonometer every two days. Each mouse was measured 6 times per eye, and the average value was taken as the intraocular pressure of the day. Within 2 days after the first injection, the intraocular pressure may increase by more than 50% and remain for about 56 days. In addition to increased intraocular pressure, it will eventually cause about 40% of optic nerve axons and ganglion cells (RGC) to be lost.

　　2, rats and rabbits are selected from 6-10 weeks old animals. One week before the operation, place the animal in a quiet place and avoid bright light. Surgical method: intraperitoneal injection of anesthesia, containing 25-30 mg/kg of 3% sodium pentobarbital. After the anesthesia is effective, the animal is fixed on the operating table. A single eye surgery was performed to create the model. Inject 0.5% four-factor eye drops into the eye, incise the conjunctiva and conjunctiva along the corneal ring by 270°. The veins on the scleral surface are separated and exposed. The veins on the scleral surface and the blood vessels around the corneal ring must be coagulated in at least 3 groups. Reposition the bulbar conjunctiva with an underwater coagulator until the blood vessel tissue becomes white. In the sham-operated control group, only the bulbar conjunctiva was removed, and the scleral surface veins and peripheral blood vessels around the corneal ring were not electrocoagulated. Apply antibacterial eye ointment to the surgical eye. After the operation, the animal was placed at room temperature and waited for it to wake up naturally. For 5 days after surgery, use antibacterial eye drops and antibacterial eye drops 3 times a day. Intraocular pressure measurement: The intraocular pressure of rats in the high intraocular pressure group and the sham operation control group was measured before the operation, 1, 2, 3, 4 and 8 weeks after the operation. Methods as below. After the anesthesia is effective, intraperitoneally inject 25-30 mg/kg of 3% sodium pentobarbital, apply 0.5% tetracaine eye drops on both eyes, measure the intraocular pressure with a tonometer, and measure each eye’s recording. 3-5 measurements. A tonometer that has just touched or left the cornea is unreliable and should be discarded.

　　3. The macaque model uses healthy adult macaques, and there are no restrictions on males and females. Before creating the model, check the condition of the animal's eyes. The angle of the chamber should be open, the optic disc should be normal, and the intraocular pressure should be normal. Inject ketamine (5 mg/kg) intramuscularly for anesthesia, instill 0.5% tetracaine into the conjunctival sac 3 times, and use an argon ion laser (with goniometer) to aim 1/3 of the trabecular meshwork at 1.2-1.5W . The energy and spot diameter are 50μm. In the first 3-5 days after the operation, it takes 0.5 seconds for the photocoagulation to be 100 points in the range of 3600 and the use of 1% prednisolone acetate (or the corresponding anti-inflammatory drug) to reduce postoperative reactions.

　　[Model Features]

　　1. The effect of the mouse model is better, it will not cause obvious damage to the eye structure or inflammation, can maintain high intraocular pressure for a long time, and may cause optic nerve axon degeneration and loss of ganglion cells.

　　2. In the 1, 2, 3, 4, and 8 week postoperative models of rats and rabbits, the intraocular pressure of the hypertensive eye was compared with the preoperative basal pressure, and the contralateral non-operated eye and the sham-operated group were compared. The difference is significant and statistically significant. significance. One week after the operation, the intraocular pressure was basically stable, and the intraocular pressure of the rat was 4.1~6.8kPa (30.12~51.18mmHg). Electrocoagulation of at least three sets of veins and peripheral blood vessels on the surface of the sclera can reduce the venous return of aqueous humor, resulting in a significant and continuous increase in intraocular pressure. The inflammatory reaction of the operated eye is mild.

　　3. The characteristic of the monkey model is that the intraocular pressure drops sharply after laser photocoagulation, and the aqueous humor flow decreases. The cause may be inflammation and damage to the ciliary body. Multiple laser photocoagulation is required to improve the success rate of the model.

　　[Model Evaluation and Application] The pathological changes of this model are mainly in the trabecular meshwork, causing the attachment of the surrounding iris, and ultimately preventing the outflow of aqueous humor and long-term intraocular pressure. Mutations and ganglion cell apoptosis (which can cause elevation) are more consistent with the pathological changes of open-angle glaucoma.