MPO and colitis: Oral nicotine (6, 12.5, 25, and 50 μg/ml, not 100 μg/ml, in drinking water), subcutaneous nicotine (0.1 mg/kg), and minipump infusion (2.5 mg/kg) attenuated the DSS-induced colitis of male C57BL/6 mice, which resulted in a significant decrease in histologic damage scores with myeloperoxidase (MPO) and TNFα reduction.