The influence of succinic acid on the apoptosis of polymorphonuclear neutrophil in peripheral blood / 中华烧伤杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the influence of succinic acid on the apoptosis of polymorphonuclear neutrophil (PMN) in human peripheral blood, and to explore its role in infection.</p><p><b>METHODS</b>PMNs were incubated in vitro, and its concentration was adjusted to 5 x 10(6)/mL. Then the cells were divided into normal control group and 5,10, 20, 30 mmol/L succinic acid groups according to different concentrations of succinic acid added into the medium. The supernatant of the cultures in each groups were collected to determine the superoxide content. 1 mL cell suspension was collected from 5, 20 mmol/L succinic acid groups before treatment and at 2, 4, 6, 8, 10 post-treatment hours (PTH) for the determination of caspase-3 activity and the apoptosis rate.</p><p><b>RESULTS</b>The content of superoxide in 5, 10, 20, 30 mmol/L succinic acid groups (0.437 +/- 0.056, 0.432 +/- 0.024, 0.395 +/- 0.049, 0.386 +/- 0.010) was significantly lower than that in control group (0.505 +/- 0.028, P < 0.05). The caspase-3 activity in each group increased along with the incubation time, but was in lower concentration in 5 mmol/L succinic acid group and in higher concentration in 20 mmol/L succinic acid group when compared with that in control group (P < 0.05). The apoptosis rate of PMN in control group was (6.1 +/- 1.1)% before incubation, and it reached (13.2 +/- 2.0)% at 2 PTH, and (27.7 +/- 3.7)% at 10 PTH. The apoptosis rate of PMN in 5 mmol/L succinic acid group was lower than that in control group except that at 4 PTH (P < 0.05). On the other hand, the apoptosis rate in 20 mmol/L succinic acid group (during 4-10 PTH) were obviously higher at each time points compared with the control group (P < 0.05).</p><p><b>CONCLUSION</b>Low concentration of succinic acid can suppress the apoptosis of PMN, while high concentration of succinic acid has an opposite effect. It is known that bacteria can produce succinic acid.</p>