title: [The influence of succinic acid on the apoptosis of polymorphonuclear neutrophil in peripheral blood].
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Burns, Xiangya Hospital, Central South University, Changsha 410008, PR China.
authors.forename: Li-Cheng
authors.initials: LC
authors.lastname: Ren
authors.forename: Xiao-Yuan
authors.initials: XY
authors.lastname: Huang
authors.forename: Pi-Hong
authors.initials: PH
authors.lastname: Zhang
authors.forename: Jian-Hong
authors.initials: JH
authors.lastname: Long
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002478:Cells, Cultured; D006801:Humans; D018375:Neutrophil Activation; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects*; D019802:Succinic Acid / Q000494:pharmacology*
chemical_list: D019802:Succinic Acid