IL6 and Parkinson disease: In accordance with another recent investigation, PACAP and VIP cotherapy markedly restrained the liberation of NO, interleukin-6 (IL-6), matrix metallopeptidase 9 (MMP-9), and cluster of differentiation molecule 11b (CD11b) in the rotenone-subjected microglial cells of mice (BV-2 cells), and therefore might contribute to considerable nerve cell protection in PD [214].