MAPK8 and Parkinson disease: The occurrence of peak RGC apoptosis and concomitant retinal swelling at 20 days could be a result of inflammation, as rotenone administration to retinal neuronal cells in vitro is documented to promote the expression of pro-inflammatory JNK and p38 MAPK pathways and PD is inherently linked to neuroinflammatory components [46, 59, 60].