title: Effects of prolonged methylprednisolone treatment after pulse therapy for paraquat-intoxicated rats.
abstract: OBJECTIVE
  This study was designed to evaluate prolonged methylprednisolone (MP) treatment after pulse therapy for paraquat (PQ)-intoxicated rats.
  
  
  METHODS
  Acute PQ toxicity was induced by intraperitoneally injecting single toxic dose of 25 mg/kg of body weight. Rats were divided into four groups: control group (saline solution for 15 days), PQ group (saline solution for 15 days after PQ toxicity), pulse group (15 mg·kg-1·day-1MP for 3 days after PQ toxicity and then saline solution for 12 days) and pulse + prolonged group (15 mg·kg-1·day-1MP for 3 days after PQ toxicity; dosage was subsequently reduced by half every 2 days, and MP was terminated until 0.47 mg·kg-1·day-1). Hydroxyproline (HYP) content in lung tissues was evaluated through enzyme-linked immunosorbent assay, and lung fibrosis was examined using a semiquantitative scoring system (Ashcroft staging criteria). Lung wet-to-dry weight (W/Dc) ratio and 15-day survival rates of the rats were also analysed.
  
  
  RESULTS
  Similar survival rates (55.0 vs. 65.0%) were obtained for the pulse group and the pulse + prolonged group. The W/Dc (4.79 ± 0.42 vs. 5.29 ± 0.35), HYP content in the lung tissues (3.23 ± 0.24 vs. 3.72 ± 0.23 μg/mg) and lung fibrosis scores (2.69 ± 0.74 vs. 3.12 ± 0.60) of the pulse + prolonged group were lower than those of the pulse group.
  
  
  CONCLUSIONS
  Prolonged MP treatment after pulse therapy could effectively ameliorate PQ-intoxicated acute lung injury in rats. However, further studies should be performed to verify our findings.
authors.affiliation: Emergency Department, Cangzhou Central Hospital, Cangzhou, Hebei, China.
authors.forename: S Y
authors.initials: SY
authors.lastname: Feng
authors.affiliation: Emergency Department, Cangzhou Central Hospital, Cangzhou, Hebei, China.
authors.forename: J
authors.initials: J
authors.lastname: Gao
authors.affiliation: Emergency Department, Cangzhou Central Hospital, Cangzhou, Hebei, China.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.affiliation: Emergency Department, Cangzhou Central Hospital, Cangzhou, Hebei, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
mesh_terms: D055371:Acute Lung Injury / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D005938:Glucocorticoids / Q000627:therapeutic use*; D006540:Herbicides / Q000633:toxicity*; D006909:Hydroxyproline / Q000378:metabolism; D008775:Methylprednisolone / Q000627:therapeutic use*; D010269:Paraquat / Q000633:toxicity*; D011658:Pulmonary Fibrosis / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D017208:Rats, Wistar
chemical_list: D000893:Anti-Inflammatory Agents; D005938:Glucocorticoids; D006540:Herbicides; D010269:Paraquat; D006909:Hydroxyproline; D008775:Methylprednisolone
keywords: Paraquat; hydroxyproline; lung fibrosis; methylprednisolone; survival rate