4.16. Carrageenan-Induced Peritonitis

ICR mice were intraperitoneally (i.p.) pretreated with SM in 10% Tween-80 (50 mg/kg), vehicle (10% Tween-80), or dexamethasone (0.5 mg/kg) as a reference anti-inflammatory drug 1 h prior to peritonitis induction by 1% carrageenan i.p. Saline buffer was also administered i.p. in the normal control group instead of carrageenan injection. Four hours after peritonitis induction, mice were sacrificed by cervical dislocation, and the peritoneal cavity was washed with 2 mL of heparinized cold saline buffer to obtain peritoneal exudates. The collected samples were centrifuged (2500 rpm, 5 min, 4 °C), the cell pellets were resuspended in 50 μl of PBS, and total leukocyte counts were performed with a Neubauer chamber by optical microscopy after diluting in Turk solution (1:20). The supernatants were collected to assess the levels of pro-inflammatory cytokines TNF-α and IL-6 using a mouse TNF-α ELISA kit and a mouse IL-6 ELISA kit (Thermo Scientific, Rockford, IL, USA) according to the manufacturer’s instructions. To determine the differential leukocyte counts, peritoneal cells were centrifuged and placed onto slides, stained with azur-eosin by the Romanovsky–Giemsa method, and examined by optical microscopy. The results were expressed as the number of total leukocytes (×10⁶/mL) and the ratio of neutrophils, lymphocytes, and monocytes (%).