动物模型,细菌性角膜炎,动物造模 z-bo 2022-02-24 439

　　[Modeling mechanism] The corneal stroma occupies 90% of the thickness of the cornea and consists of 100 to 200 layers of regularly arranged collagen fibers, and there are a small amount of endogenous corneal cells between the corneal lamellar fibers. When the cornea is damaged and inflamed, these cells are induced to evolve into fibroblasts and can participate in the repair of damaged areas. The cornea is avascular, and its nutrition comes from aqueous humor, tear film and limbal capillaries. In bacterial keratitis (bacterial keratitis), epithelial cells and parenchymal cells in the inflammatory stage of injury also release proteolytic enzymes, causing the ulcer to deepen and spread. The conjunctiva and lacrimal gland are also involved in inflammatory reactions, manifested by conjunctival swelling and hyperemia, lymphocytes, monocytes and neutrophils increase, and tears can flush the conjunctival sac and corneal surface. Tears contain some bactericidal lysozyme and immunoglobulin. However, the speed of body repair is related to the degree of corneal damage, the toxicity of bacteria and the number of infected bacteria. Pseudomonas aeruginosa is currently the most pathogenic bacteria in ophthalmology. Bacteria produce a variety of decomposing enzymes, causing local tissue decomposition, causing the body's inflammatory response to bacteria, and even destroying and destroying corneal tissue.

　　[Modeling method] Choose a healthy rabbit weighing about 2.0 kg, and there are no restrictions on males and females. Before modeling, perform an external visual inspection and use normal modeling. Before creating the model, prepare the bacterial inoculum. Inoculate Pseudomonas aeruginosa stored in a refrigerator at 4°C on a normal agar medium, and incubate at 36°C for 24 to 48 hours. Scratch the colony with platinum earrings and prepare it with saline. The concentration is 2 x 1000000000/ml (the concentration is measured by a photoelectric turbidimeter). When creating the model, tetracaine applied local anesthesia to the rabbit eyes. Even if the cornea was used to press the cornea, there was no response, so please gently press the cornea and rotate it clockwise, and then use the 7 mm and 4 mm diameter corneal cyclopentane Surrounded by four acids. Cause trauma. Pull the eyelid into a cup, and use a 1 ml syringe to drop 2 x 1000000000/ml bacteria into the eye of 0.1 ml/rabbit to infect one eye. Twenty-four hours later, observe and record eye symptoms for seven consecutive days.

　　Grade 0: The eyes are bright and there is no discharge. Grade 0.5: Discharge is found, eyes are slightly red and swollen. Level 1: The secretion range is less than 6 mm. Level 2: The secretion range reaches 6 mm. Grade 3: The secretion range is greater than 6 mm. ..

　　At 1, 3, and 5 days after infection, use infected sterile saline swabs to collect secretions from infected and control eyes and put them in 4 ml saline. Mix (solution to be tested). Pipette 1 ml of the test solution into a sterile petri dish (90 mm in diameter), heat to melt, and then pour the nutrient agar cooled to about 45°C into a 15 ml petri dish, gently clockwise Shake to condense. Place in a 36°C incubator for 24 hours. To determine whether the bacteria is negative or positive.

　　[Model Features] 24 to 48 hours after inoculation, the affected eye has a lot of yellowish discharge, severe conjunctival hyperemia, corneal opacity, closed eyes and purulent discharge, making the eyelids sticky and mild. The iris pupil covering the entire cornea is almost invisible, and the iris pupil eliminates the secretions of the rabbit eye. Except for some eyes with a score of 2.0 on day 5, most eyes can achieve a score of 3.0. Bacterial culture results: positive secretory culture on the first 1, 3 and 5 days after inoculation. Pathological sections of the cornea showed that the cornea was highly edema and turbid, and a large number of neutrophils, lymphocytes, fibroblasts and necrotic tissue were found in the first 1/3 of the stroma. The subepithelial ulcer did not heal. New blood vessels were found in the corneal stroma, corneal perforation and anterior chamber empyema also appeared in some areas. The blood vessels of the iris are dilated, congested, and infiltrated by a large number of inflammatory cells. [Model Evaluation and Application] A method of using corneal cyclopentane to destroy the cornea, which is easy to operate and easy to learn. However, due to the different severity of the model builder technology, the depth of corneal injury is variable, and the experimental groups are divided into groups according to the scoring criteria, thereby significantly distinguishing the degree of inflammation in each group of animal models. No. The animal model established in this way is suitable for clinical screening of antibacterial drugs.