The effect of propofol on cytotoxicity and apoptosis of lipopolysaccharide-treated mononuclear cells and lymphocytes

IV anesthetics may inhibit proper immune responses and further compromise an already depressed defense system. To assess the possible role of propofol on human immune function in sepsis, we studied cytotoxicity, and apoptosis of mononuclear cells (MNCs). Peripheral blood MNCs were preincubated in 1 μg/mL of lipopolysaccharide (LPS) and then reincubated in different concentrations of propofol (1 μg/mL, 5 μg/mL, 10 μg/mL, or 50 μg/mL). To determine cytotoxicity, lactate dehydrogenase release was assayed by mixing MNCs (4 × 10⁵/100 μL) with K-562 tumor cells as target cells (1 × 10⁴/100 μL)(E: T ratio of 40:1). Apoptosis was determined by measuring the annexin positive cells using flow cytometry. Cytotoxicity and apoptosis of LPS-treated MNCs were unchanged by clinically acceptable concentrations of propofol (1 μg/mL, 5 μg/mL, and 10 μg/mL). However, significant differences were observed in cytotoxicity (P = 0.004) and apoptosis (P = 0.002) with propofol 50 μg/mL. By gating MNCs, we found that lymphocyte apoptosis was significantly increased at 50 μg/mL of propofol, but monocytes were unaffected (P = 0.02). In terms of cytotoxicity and apoptosis, propofol allowed MNCs to retain their cytotoxicity in septic conditions by protecting immune cells from apoptosis.