Mice
Male BALB/c mice (7 weeks of age) were obtained from the Animal Resource Centre (Perth, Australia). Mice were housed in micro-isolator cages at 21°C on a 12-hour day/night cycle with free access to food and water. After four days of acclimatization, mice were randomly assigned to room air (sham) and cigarette smoke (smoke) exposure groups with or without daily supplementation of apocynin (5 mg·kg-1) via intraperitoneal (i.p.) injection. The vehicle groups were injected with saline (solvent of apocynin). Mice were weighed three times a week with daily monitoring. All experiments were conducted in accordance with the Australian Code of Practice for the Care of Experimental Animals, the ARRIVE Guidelines and with RMIT University Animal Ethics Committee approval (Animal Ethics Application Number 1521).