title: Effect of recombinant adenovirus coding for endomorphin-2 on neuropathic pain in rats.
abstract: OBJECTIVE
  To construct a transgene expressing human endomorphin-2 by linking the signal peptide of mouse nerve growth factor (PN) to a human endomorphin-2 DNA sequence containing a short linker recognized by the protease FURIN and test the analgesic effect of endomorphin-2 on neuropathic pain.
  
  
  METHODS
  The transgene was inserted into the cosmid pAxCAwt to generate PN-EM-2-pAxCAwt. The recombinant adenovirus Ad-PNEM2 was packaged and propagated in HEK293 cells. After the Ad-PNEM2-infected NIH3T3 cells had been cultured, protein expression was examined by immunofluorescence and ELISA. A CCI rat model was constructed and the Ad-PNEM2 was administered intrathecally. The rats' pain thresholds (PWL) were measured and the presence of endomorphin-2 in the cerebrospinal fluid was confirmed through ELISA.
  
  
  RESULTS
  The Ad-PNEM2 expressed endomorphin-2 smoothly and abundantly in NIH3T3 cells at a significantly higher rate than the viral control (P<0.01) or blank control (P<0.01). The expressed endomorphin-2 was mainly observed in the cytoplasm. The concentration of endomorphin-2 in the cerebrospinal fluid increased 1 day after injection and peaked between 7 and 14 days after injection. After injection, PWL approached normal levels in the operated study group. No significant change was observed in the control groups. There was a significant correlation between PWL and endomorphin-2 level (r = 0.944, P<0.001).
  
  
  CONCLUSIONS
  The constructed human endomorphin-2 transgene was expressed effectively, and endomorphin-2 expressed by the recombinant adenovirus altered the threshold to thermal stimulus and showed good analgesic effect.
authors.affiliation: Department of Anesthesiology, Eastern Hepatobiliary Hospital, Shanghai 200433, China.
authors.forename: Feixiang
authors.initials: F
authors.lastname: Wu
authors.forename: Xuewu
authors.initials: X
authors.lastname: Xu
authors.forename: Xuerong
authors.initials: X
authors.lastname: Miao
authors.forename: Jiaying
authors.initials: J
authors.lastname: Chen
authors.forename: Yuming
authors.initials: Y
authors.lastname: Sun
authors.forename: Weifeng
authors.initials: W
authors.lastname: Yu
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D057809:HEK293 Cells; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D051379:Mice; D041681:NIH 3T3 Cells; D020932:Nerve Growth Factor / Q000235:genetics / Q000378:metabolism; D009437:Neuralgia / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D009842:Oligopeptides / Q000134:cerebrospinal fluid / Q000235:genetics / Q000378:metabolism*; D010147:Pain Measurement; D017288:Pain Threshold; D021382:Protein Sorting Signals / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time; D013997:Time Factors; D014162:Transfection
chemical_list: D009842:Oligopeptides; D021382:Protein Sorting Signals; C105294:endomorphin 2; D020932:Nerve Growth Factor
keywords: Endomorphin-2; adenovirus; gene therapy; nerve growth factor; pain