Degeneration of Phrenic Motor Neurons Induces Long-Term Diaphragm Deficits following Mid-Cervical Spinal Contusion in Mice.

Abstract A primary cause of morbidity and mortality following cervical spinal cord injury (SCI) is respiratory compromise, regardless of the level of trauma. In particular, SCI at mid-cervical regions targets degeneration of both descending bulbospinal respiratory axons and cell bodies of phrenic motor neurons, resulting in deficits in the function of the diaphragm, the primary muscle of inspiration. Contusion-type trauma to the cervical spinal cord is one of the most common forms of human SCI; however, few studies have evaluated mid-cervical contusion in animal models or characterized consequent histopathological and functional effects of degeneration of phrenic motor neuron-diaphragm circuitry. We have generated a mouse model of cervical contusion SCI that unilaterally targets both C4 and C5 levels, the location of the phrenic motor neuron pool, and have examined histological and functional outcomes for up to 6 weeks post-injury. We report that phrenic motor neuron loss in cervical spinal cord, phrenic nerve axonal degeneration, and denervation at diaphragm neuromuscular junctions (NMJ) resulted in compromised ipsilateral diaphragm function, as demonstrated by persistent reduction in diaphragm compound muscle action potential amplitudes following phrenic nerve stimulation and abnormalities in spontaneous diaphragm electromyography (EMG) recordings. This injury paradigm is reproducible, does not require ventilatory assistance, and provides proof-of-principle that generation of unilateral cervical contusion is a feasible strategy for modeling diaphragmatic/respiratory deficits in mice. This study and its accompanying analyses pave the way for using transgenic mouse technology to explore the function of specific genes in the pathophysiology of phrenic motor neuron degeneration and respiratory dysfunction following cervical SCI.JOURNAL ARTICLESCOPUS: ar.jinfo:eu-repo/semantics/publishe

Efeito de diferentes níveis de proteína e energia sobre o rendimento de carcaça de codornas européias Effect of protein and energy levels on carcass yield of European quails

Avaliou-se o rendimento de carcaça de codornas européias de corte (Coturnix coturnix coturnix) no 42º dia de idade, alimentadas com dietas contendo quatro níveis de proteína e dois níveis de energia. O delineamento experimental foi inteiramente ao acaso, com seis repetições e oito codornas por unidade experimental. Os tratamentos constituíram de um fatorial 2×4, ou seja, dois níveis de energia (2900 e 3100kcal EM/kg) e quatro níveis de proteína (22, 24, 26 e 28% proteína bruta na dieta). As variáveis estudadas foram: peso vivo, peso de carcaça, rendimento de carcaça, peso de coxa, rendimento de coxa, peso de peito, rendimento de peito, peso de gordura abdominal, rendimento de gordura abdominal, peso de vísceras comestíveis e rendimento de vísceras comestíveis. Não houve efeito significativo dos níveis de energia e nem dos níveis de proteína sobre nenhuma das características de carcaça analisada.<br>The effect of protein and energy levels on 42nd day carcass yield of European quails (Coturnix coturnix coturnix) was evaluated. A completely randomized design with five replicates and eight quails per experimental unit was used. The treatment consist on diets with two energy metabolic levels (2900 and 3100kcal EM/kg) and four protein levels (22, 24, 26 and 28% of crude protein). The traits analyzed were body weight and weight and yield of carcass, tight, breast, fat and edible viscera. No significant effects of crude protein and metabolic energy levels on carcass traits were found