Abstract
Abstract: :
Purpose: Dry eye is a complex multifactorial disease characterized by an immune and inflammatory process that affects the lacrimal glands and the ocular surface. Numerous dry eye animal models which simulate Sjögren’s, non–Sjögren’s, and evaporative, dry eye have been developed. Most of these models have a single causative mechanism, and do not take into consideration the interplay of temperature, humidity and air flow parameters which are so critical in affecting the clinical presentation of the condition, and hence are deficient in truly mimicking important aspects of the disease. Therefore, a new animal model of dry eye incorporating controllable environmental factors will address these deficiencies and help in assessing the efficacy of novel therapeutics. Methods: A standard cage for mice has been developed which uses different desiccant materials, and adapted to support a probe connected with a continuous temperature (T) (range 5–45°C) and relative humidity (RH) (0–100%) recorder (6 hours–31 days). The air (ambient or dehumidified) flow is regulated by a flowmeter (0–50 l/min) with a valve placed on the air line. The source of air is a small silent compressor placed 5 feet from the cage and on a different level, in order to minimize any influence on the animal behaviour. A humidifier is connected to the cage. Results: Despite the room RH where the cage is placed, in our system RH constantly increases in the first 3 hours to a steady state level of 47.7% ± 3.5%. Two different desiccants can maintain a RH of respectively 28.5% ± 2.1%, and 15% ± 2.8%, after 3 hours. The humidifier can increase RH up to 100%. The air flow can be regulated from 0 to 25 l/min. The temperature in the system can be held constant (21°C). Conclusions: Our controlled environment cage may be used to induce dry eye in mice, and to measure the influence of T, RH and air flow on the ocular surface of various mouse models.
Keywords: cornea: tears/tear film/dry eye • anterior segment • cornea: basic science