[Animal model]-Candida albicans infection keratitis model
动物模型,白色念珠菌
z-bo
2020-07-25
708
(1) Replication method Inoculate Candida albicans in sabo medium, culture at 28°C for 3 days, wash with 1 ml of saline, transfer to a grinder and dilute, count the red blood cell counter, the inoculation concentration is 10000000 CFU / Is milliliter. .. An adult rabbit weighing 1.5-2.5 kg was sacrificed by air embolization via the ear vein, and the eyes were removed under aseptic conditions to produce a corneal implant with a 2 mm scleral ring. Put it in sterile glycerin and freeze for later use. Three days before the experiment, 0.5% chloramphenicol eye drops were applied to the eye drops four times a day. Before the experiment, the animals were anesthetized with a mixture of ketamine hydrochloride (50 mg/kg body weight), chlorpromazine hydrochloride (10 mg/kg body weight) and atropine sulfate (0.015 mg/kg body weight). After intraocular injection, the cornea was anesthetized with 2 ml of 2% lidocaine. Under aseptic conditions, soak the corneal implant in normal saline for 10 minutes at room temperature, then gently scrape the recipient’s corneal epithelium with a scalpel, and use 10-0 nylon thread to connect the donor’s cornea The graft is sutured radially to the cornea of the recipient. Then use a syringe to inject 0.1 ml of bacterial solution into the center of the cornea between the implant and the implant bed. Gentamicin was injected subconjunctivally with 20,000 U, and erythromycin ointment was applied to the eyes. After the operation, 0.5% chloramphenicol eye drops were instilled 4 times a day, and the corneal graft was removed 48 hours after the operation. Typical corneal fungal damage can be seen on the second day after inoculation.
(2) Model features: The corneal surface lens technology can be used to inoculate fungi between the corneal implant and the implant bed to establish a rabbit keratitis model without the use of corticosteroids. The corneal implant is fixed with sutures, and the space between the layers is stable, so that the fungus is in perfect contact with the corneal surface of the wound, thereby creating a good environment for the survival and reproduction of the fungus. As a result, the number of fungal bacteria required is relatively low, the successful infection rate is high, the reproducibility is good, the corneal graft is easy to obtain, and cross-infection does not occur, but the operation process of this method is relatively complicated and correct The experimenter's surgical skills have certain requirements. Typical corneal fungal damage can be seen on the second day after inoculation. Candida albicans hyphae grow vertically on the corneal plate and are scattered with round spores. Eight days after the inoculation, the hyphae grew into the deep interstitial layer of the cornea. The occurrence of fungal keratitis is related to pathogens, pathogenicity of fungi, immune status and number of fungi. The corneal method not only establishes keratitis caused by Candida albicans, but also establishes keratitis models of various strains such as Aspergillus fumigatus, Fusarium solanum, and Penicillium chrysogenum. The degree of disease is different, but the success rate of infection is different. High and easy to repeat. (3) Comparative medicine Fungal keratitis (FK) is an infectious corneal disease with a high rate of blindness, and in severe cases, the eyes will be lost. Foreign research reports have successfully used inbred NIHSwiss mice and inbred BALB/c mice to establish animal models of fungal keratitis. However, due to the small size of the mouse cornea, surgery is difficult, few samples can be obtained after infection, and it is not useful for observing common forms of fungal infection. Currently, rabbits are the most commonly used model animals in most studies of fungal eye infections. Since rabbit cornea is larger than human cornea, surgery and local observation are easy, and more experimental samples can be obtained. So far, more than 70 fungi have been found to cause corneal infections. The main pathogens vary from region to region. Candida albicans, Fusarium and Aspergillus are the main pathogens. The traditional method of preparing animal models for fungal corneal infections is corneal stroma injection. The prefabricated fungal liquid is injected into the central stromal layer of the animal's cornea through a syringe. However, in clinical cases of fungal keratitis, this animal model is different from the natural course of surface infection. the same. Some researchers inoculate animals with corticosteroids subconjunctivally before inoculating fungi to increase the infection rate and maintain persistent infection. This model is mainly used to study the efficacy and diagnostic methods of fungal keratitis. Since the end of the last century, foreign scholars have invented the contact lens method. The central epithelium of the rabbit cornea is completely scraped off, and then covered with soft contact lenses. Then Candida albicans is injected between the contact lens and the corneal layer. This method is similar. The process of human corneal infection can be applied to the histopathological study of candidal keratitis. This model replicates the rabbit keratitis model using corneal surface lens technology. Compared with other replication models, this model approximates the natural course of clinical fungal keratitis.
