Although C. elegans is commonly used to assess the neurotoxicity of environmental pollutants, studies that explore the intricate biology of its nervous system, particularly those addressing long term effects and aging in adult worms, are rare. These models offer significant advantages for understanding the full spectrum of neurobiological impacts. Here, we investigated the effects of silica nanomaterials on the GABAergic neural system in young to middle-aged nematodes. Results showed a novel degeneration pattern characterized by loss of anterior- and posteriormost GABAergic D-type motor neurons. Proteomics of 4-day-old C. elegans revealed significant alterations of protein abundance including the downregulation of proteins such as glutamate dehydrogenase (gdh-1), and glutamate oxaloacetate transaminase (got-1.2) which are essentially involved in GABA metabolic pathways.