title: Effects of CpG Oligodeoxynucleotide 1826 on transforming growth factor-beta 1 and radiation-induced pulmonary fibrosis in mice.
abstract: BACKGROUND
  Cytosine-phosphate-guanine (CpG) oligodeoxyribonucleotides (ODNs) are synthetic DNA fragments containing unmethylated cytosine-guanine motifs with potential immune modulatory effects and have recently been suggested to enhance sensitivity to traditional therapies in lung cancer. This study aimed to examine the effects of CpG ODN1826 on transforming growth factor-beta 1(TGF-β1) and radiation-induced pulmonary fibrosis in mice.
  
  
  METHODS
  The radiation-induced pulmonary fibrosis mouse model was established by a single dose of 20 Gy, 6 MV X-rays exposure to the left lung. ICR mice were evenly randomized into four groups, comprising: a control group, a radiation group (RT group), a CpG group and a radiation combined with CpG ODN1826 group (RT + CpG group), with 40 mice in each group. CpG ODN1826 was intraperitoneally injected into mice at 1, 3, 5, 7 and 9 d post-irradiation. The mice were sacrificed at 1, 5, 15, 30 and 90 d post-irradiation. Paraffin sections of the radiated lung were subjected to H&E staining and Masson staining. The Ashcroft scale was used for quantitative histological analysis of fibrotic changes induced by irradiation. Concentrations of serum TGF-β1 were determined by ELISA, and concentrations of Hydroxyproline(Hyp) in the lung were determined with the alkaline hydrolysis method. Relative gene expression of FoxP3 was determined by real-time PCR.
  
  
  RESULTS
  The radiation-induced pulmonary fibrosis mouse model was successfully established. The serum concentrations of TGF -β1 of RT group were higher than those of the RT + CpG group (t = 5.212, 7.126, 7.972 and 3.785, P < 0.05). The Hyp in the lung of RT group was higher than that of RT + CpG group (t = 4.606, P < 0.05). The relative expressions of FoxP3 gene in the lung of the RT group were higher than those of RT + CpG group (t = 8.395, 5.099 and 6.147, P < 0.05).
  
  
  CONCLUSIONS
  CpG ODN1826 could reduce the serum concentrations of TGF-β1 and the lung content of Hyp in radiation-induced pulmonary fibrosis, which might be related to the possibility that CpG ODN1826 can reduce expression of the FoxP3 gene.
authors.affiliation: Department of Radiation Oncology, Jinshan Hospital, Fudan University, Shanghai, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Li
authors.affiliation: Central Laboratory, Jinshan Hospital, Fudan University, Shanghai, China.
authors.forename: Guoxiong
authors.initials: G
authors.lastname: Xu
authors.affiliation: Department of Radiation Oncology, Jinshan Hospital, Fudan University, Shanghai, China.
authors.forename: Tiankui
authors.initials: T
authors.lastname: Qiao
authors.affiliation: Department of Radiation Oncology, Jinshan Hospital, Fudan University, Shanghai, China.
authors.forename: Sujuan
authors.initials: S
authors.lastname: Yuan
authors.affiliation: Department of Radiation Oncology, Jinshan Hospital, Fudan University, Shanghai, China.
authors.forename: Xibing
authors.initials: X
authors.lastname: Zhuang
authors.affiliation: Central Laboratory, Jinshan Hospital, Fudan University, Shanghai, China.
authors.forename: Jihong
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY USA.
authors.forename: Hui Bin
authors.initials: HB
authors.lastname: Sun
keywords: CpG Oligodeoxynucleotide1826; FoxP3; Radiation pulmonary fibrosis; TGF-β1