title: Assessment of dose-effect and therapeutic time window in preclinical studies of rhEGF and GHRP-6 coadministration for stroke therapy.
abstract: BACKGROUND
  Stroke continues to be a leading cause of mortality and morbidity worldwide, and novel therapeutic options for ischaemic stroke are urgently needed. In this context, drug combination therapies seem to be a viable approach, which has not been fully explored in preclinical studies.
  
  
  OBJECTIVE
  In this work, we assessed the dose-response relationship and therapeutic time window, in global brain ischaemia, of a combined therapeutic approach of recombinant human epidermal growth factor (EGF) and growth hormone-releasing peptide-6 (GHRP-6).
  
  
  METHODS
  Mongolian gerbils underwent 15 minutes occlusion of both common carotid arteries. Four different doses of rhEGF, GHRP-6 and these combined agents were intraperitoneally administered immediately after the onset of reperfusion. Having identified a better response with both agents, rhEGF+GHRP-6 were administered at 2, 4, 6, 8 or 24 hours after the onset of reperfusion to assess the time window of effectiveness. Animals were evaluated daily for neurological deficits. Three days post-occlusion, the animals were sacrificed and 2,3,5-triphenyltetrazolium chloride was used to quantify infarcted tissues.
  
  
  RESULTS
  The coadministration of rhEGF and GHRP-6 at doses of 100 and 600 μg/kg, respectively, administered up to 4 hours following the ischaemic insult, significantly improved survival and neurological outcome, and reduced infarct volume compared with vehicle treatment. These results are considered as an additional proof of concept as supporting a combined therapeutic approach and justify the further development of this preclinical research.
authors: a Biomedical Research Division , Center for Genetic Engineering and Biotechnology , Havana , Cuba.
authors: Nelvys
authors: N
authors: Subirós
authors: a Biomedical Research Division , Center for Genetic Engineering and Biotechnology , Havana , Cuba.
authors: Héctor M
authors: HM
authors: Pérez-Saad
authors: a Biomedical Research Division , Center for Genetic Engineering and Biotechnology , Havana , Cuba.
authors: Jorge A
authors: JA
authors: Berlanga
authors: a Biomedical Research Division , Center for Genetic Engineering and Biotechnology , Havana , Cuba.
authors: Lizet
authors: L
authors: Aldana
authors: b Group of Stability and Reference Materials , Quality Control Division, Center for Genetic Engineering and Biotechnology , Havana , Cuba.
authors: Gerardo
authors: G
authors: García-Illera
authors: c School of Psychology , University of Leicester , UK.
authors: Claire L
authors: CL
authors: Gibson
authors: a Biomedical Research Division , Center for Genetic Engineering and Biotechnology , Havana , Cuba.
authors: Diana
authors: D
authors: García-Del-Barco
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D004815:Epidermal Growth Factor / Q000627:therapeutic use*; D005849:Gerbillinae; D006801:Humans; D008297:Male; D009460:Neurologic Examination; D009842:Oligopeptides / Q000627:therapeutic use*; D020521:Stroke / Q000188:drug therapy* / Q000473:pathology; D013997:Time Factors
chemical_list: D009842:Oligopeptides; C041048:growth hormone releasing hexapeptide; D004815:Epidermal Growth Factor
keywords: Combined therapy; EGF; GHRP-6; Neuroprotection; Stroke; Therapeutic time window