passages.id: split_1_test_2905_passage
passages.type: progene_text
passages.text: Mice homozygous for the spontaneous motor neuron degeneration mutation ( mnd ) show at the age of 8 months a marked impairment of the motor function and accumulation of lipofuscin granules in the cytoplasm of almost all neurons of the central nervous system.We previously reported a significant increase in GFAP protein levels in the lumbar spinal cord homogenates by western blot analysis and upregulation of TNF , a proinflammatory cytokine , in the motor neurons of lumbar spinal cord of mnd mice , already in a presymptomatic stage ( 4 months of age ) .