RESUMO
The neuroprotective effect of epidermal growth factor (EGF) has been documented in different contexts, but its potential benefits in peripheral neuropathies have been little studied. We investigated the neuroprotective action of EGF in experimental neuropathy induced by acrylamide (ACR). Mice and rats were treated chronically with acrylamide for 6 and 8 weeks, respectively. Concurrently they received EGF in daily doses of 1 and 5 mg/kg in mice and 3 mg/kg in rats, or saline (PBS). ACR severely affected the neurological score, the muscle strength, and the muscle potential M, in mice, as well as F-waves (F-Wii), sensory potentials (SPii), and apomorphine-induced penile erection, in rats. EGF reduced the ACR effects in both species. A dose-dependent effect of EGF was manifested in the proportion of diseased animals at the end of treatments, as well as in the reduction of M amplitude throughout the treatment. F-Wii parameters were less protected by EGF than SP. The results show a protective effect of EGF in acrylamide-induced neuropathy and support previous studies concerning the neuroprotective action of this peptide.
Assuntos
Acrilamida/toxicidade , Fator de Crescimento Epidérmico/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Potenciais de Ação/fisiologia , Animais , Apomorfina/farmacologia , Modelos Animais de Doenças , Agonistas de Dopamina/farmacologia , Estimulação Elétrica , Fator de Crescimento Epidérmico/química , Força da Mão/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Exame Neurológico , Fármacos Neuroprotetores/química , Ereção Peniana/efeitos dos fármacos , Ratos , Ratos Wistar , Fatores de TempoRESUMO
BACKGROUND: Combined therapy with epidermal growth factor (EGF) and growth hormone-releasing peptide 6 (GHRP-6) in stroke models has accumulated evidence of neuroprotective effects from several studies, but needs further support before clinical translation. Comparing EGF + GHRP-6 to hypothermia, a gold neuroprotection standard, may contribute to this purpose. OBJECTIVES: The aims of this study were to compare the neuroprotective effects of a combined therapy based on EGF + GHRP-6 with hypothermia in animal models of (a) global ischemia representing myocardial infarction and (b) focal brain ischemia representing ischemic stroke. METHODS: (a) Global ischemia was induced in Mongolian gerbils by a 15-min occlusion of both carotid arteries, followed by reperfusion. (b) Focal brain ischemia was achieved by intracerebral injection of endothelin 1 in Wistar rats. In each experiment, three ischemic treatment groups - vehicle, EGF + GHRP-6, and hypothermia - were compared to each other and to a sham-operated control group. End points were survival, neurological scores, and infarct volume. RESULTS: (a) In global ischemia, neurological score at 48-72 h, infarct volume, and neuronal density of hippocampal CA1 zone in gerbils treated with EGF + GHRP-6 were similar to the hypothermia-treated group. (b) In focal ischemia, the neurologic score and infarct volume of rats receiving EGF + GHRP-6 were also similar to animals in the hypothermia group. DISCUSSION: With hypothermia being a good standard neuroprotectant reference, these results provide additional proof of principle for EGF and GHRP-6 co-administration as a potentially neuroprotective stroke therapy.