title: Effects of 5-aminolevulinic acid-mediated sonodynamic therapy on macrophages.
abstract: BACKGROUND
  Inflammatory cells exhibit an elevated level of protoporphyrin IX (PpIX) after the administration of 5-aminolevulinic acid (ALA). Here, we investigate the sonodynamic effects of ALA-derived PpIX (ALA-PpIX) on macrophages, which are the pivotal inflammatory cells in atherosclerosis.
  
  
  RESULTS
  Cultured THP-1 macrophages were incubated with ALA. Fluorescence microscope and fluorescence spectrometer detection showed that intracellular PpIX increased with the concentration of ALA in the incubation solution in a time dependent manner; the highest level of intracellular PpIX was observed after 3-hour incubation. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assays demonstrated that lower concentrations (less than 2 mM) of ALA have no influence on cell viability (more than 90% of cells survived), but sonodynamic therapy (SDT) with a low concentration of ALA significantly decreased the survival rate of cells, and the effect was increased with both ALA concentration and ultrasound exposure time. Cell apoptosis and necrosis induced by ALA-mediated SDT (ALA-SDT) were measured using Hoechst 33258 and propidium iodide assay. ALA-SDT induced both cell apoptosis and necrosis, and the maximum apoptosis/necrosis ratio was observed at 6 hours after SDT with 1 mM of ALA and 5 minutes of ultrasound exposure. Flow cytometry analysis showed that ALA-SDT significantly increased late stage apoptotic cells (about 10-fold control). Furthermore, ALA-SDT induced reactive oxygen species generation in THP-1 macrophages immediately after the treatment and a conspicuous loss of mitochondrial membrane potential (MMP) at 6 hours compared with that of the control, ALA alone, and ultrasound alone groups.
  
  
  CONCLUSIONS
  ALA-SDT exhibited synergistic apoptotic effects on THP-1 macrophages, involving excessive intracellular reactive oxygen species generation and MMP loss. Therefore, ALA-SDT is a potential treatment for atherosclerosis.
authors: Division of Cardiology, the First Affiliated Hospital, Cardiovascular Institute, Harbin Medical University, Harbin, People's Republic of China.
authors: Jiali
authors: J
authors: Cheng
authors: Xin
authors: X
authors: Sun
authors: Shuyuan
authors: S
authors: Guo
authors: Wei
authors: W
authors: Cao
authors: Haibo
authors: H
authors: Chen
authors: Yinghua
authors: Y
authors: Jin
authors: Bo
authors: B
authors: Li
authors: Qiannan
authors: Q
authors: Li
authors: Huan
authors: H
authors: Wang
authors: Zhu
authors: Z
authors: Wang
authors: Qi
authors: Q
authors: Zhou
authors: Peng
authors: P
authors: Wang
authors: Zhiguo
authors: Z
authors: Zhang
authors: Wenwu
authors: W
authors: Cao
authors: Ye
authors: Y
authors: Tian
mesh_terms: D000622:Aminolevulinic Acid / Q000494:pharmacology*; D000704:Analysis of Variance; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000187:drug effects*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D011524:Protoporphyrins / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014464:Ultrasonic Therapy; D014465:Ultrasonics / Q000379:methods*
chemical_list: D011524:Protoporphyrins; D017382:Reactive Oxygen Species; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX
keywords: 5-aminolevulinic acid; atherosclerosis; macrophage; protoporphyrin IX; sonodynamic therapy