LPS-induced air pouch murine model of inflammation

Air-pouches were created according to a modified method described in the study by Sedgwick et al (43). An area of dorsal skin (4 cm²) was shaved, and 3 ml of sterile air were subcutaneously injected to establish a single air-pouch in 6-week-old black (C57BL/6) mice. The mice were anaesthetized by an intraperitoneal (i.p) injection of ketamine at 100 mg/kg together with xylazine at 10 mg/kg, prior to the subcutaneous injections during the LPS-induced air-pouch model of inflammation. The mice weighed approximately 20 g and were housed in filtered-air laminar-flow cabinets at a controlled temperature (22±2°C) with a 12-h light/dark cycle. A total of 3 ml of sterile air were administered on alternate days to maintain the pouch. At 10 days after air-pouch formation, the pouches were injected with a single dose of 1 ml (1 μg/ml) LPS alone (positive control) or a single dose of 1 ml (1 μg/ml) LPS plus a single dose of (3 or 6 or 9 mg/mouse) BAT concurrently or a single dose of 1 ml (1 μg/ml) LPS plus a single dose of (9 mg/mouse) taurine concurrently, inside the air pouches of the mice for 8 h, as previously described (44). Each group was composed of 3 mice. This air pouch model of inflammation has been similarly used in a wide range of studies (44-48). Inflammatory exudates were then harvested by collecting the lavage fluids after washing the air-pouch cavities with 2 ml PBS (1X, pH 7.4) followed by RNA extraction. The pouch membranes were fixed in 10% (v/v) buffered formalin for histological analysis.