Neuroprotective effect of tempol (4 hydroxy-tempo) on neuronal death induced by sciatic nerve transection in neonatal rats.
Peripheral nerve injury in newborn rats triggers extensive neuronal death within the spinal cord. Because most neurodegeneration is related to oxidative stress and apoptosis, the use of antioxidants may be of therapeutic interest. Tempol is promising because of its ability to chelate reactive oxygen species and to minimize or even prevent tissue damage. Here, we evaluated neuroprotective effects of tempol following neonatal sciatic nerve transection. Two-day-old pups underwent sciatic nerve axotomy followed by tempol (12, 24 and 48 mg/kg) treatment (i.p.) at 10 min, 6 h, and every 24 h up to 1 week after injury. The rats were then killed for lumbar intumescence analysis. Nissl staining, TUNEL, synaptophysin immunolabeling and qRT-PCR (Caspase 3, Bax and Bcl2) were carried out. The results indicated that tempol treatment, at 24 mg/kg, increased up to 21% spinal cord motoneuron survival (p<0.001), also preserving pre-synaptic terminals in the neuropile. Likewise, the TUNEL-positive cell number decreased in tempol-treated animals. qRT-PCR results indicated differential increase in Caspase 3 (3-fold), Bax (13-fold) and Bcl2 (28-fold) gene expression, after 12 h following axotomy and tempol treatment. In conclusion, tempol administration has proven to be neuroprotective after neonatal nerve injury, leading to improved motoneuron survival, synapse preservation and minimizing apoptosis.
Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), CP 6109, CEP 13083-907 Campinas, SP, Brazil.
Gabriela Bortolança
GB
Chiarotto
Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), CP 6109, CEP 13083-907 Campinas, SP, Brazil.
Luisa
L
Drummond
Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), CP 6109, CEP 13083-907 Campinas, SP, Brazil.
Gabriela
G
Cavarretto
Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), CP 6109, CEP 13083-907 Campinas, SP, Brazil.
André Luis
AL
Bombeiro
Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), CP 6109, CEP 13083-907 Campinas, SP, Brazil. Electronic address: alroliv@unicamp.br.
Alexandre Leite Rodrigues
AL
de Oliveira
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002470:Cell Survival; D003497:Cyclic N-Oxides / Q000494:pharmacology*; D009046:Motor Neurons / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000187:drug effects* / Q000293:injuries / Q000378:metabolism / Q000473:pathology*; D013113:Spin Labels
D003497:Cyclic N-Oxides; D018696:Neuroprotective Agents; D019253:Proto-Oncogene Proteins c-bcl-2; D013113:Spin Labels; D053148:Caspase 3; C001803:tempol
Apoptosis; Neuronal survival; Neuroprotection; Sciatic nerve; Spinal cord; Tempol