Abstract: Objective To establish a new method for observable, easy and accurate non-invasive intratracheal instillation in rats. Methods Disposable medical syringes and capillaries were used to make the sampler. Optical fiber was used to achieve visualization. Soap water was used to check if the intubation is correct. Sampler was introduced into rat trachea through endotracheal tube. Twenty rats were randomly divided into two groups and instilled with 0.9% saline solution or fine particulate matter (PM_2.5) suspension, respectively. Results The operation were performed successfully for 120 times in the 20 rats. HE staining was observed after 24 h of the last instillation. The pathological morphological changes of the lungs were induced by intratracheal instillation of PM_2.5, which were similar to those of chronic obstructive pulmonary disease (COPD). Conclusion The improved method of non-invasive intratracheal instillation is simple, rapid, and safe, and requires no special equipment, which can be widely used in experiments for respiratory tract administration.

Key words: Rat, Endotracheal instillation, Non-invasive, Animal experimental techniques