Cytokine and Neurotrophic Factor Quantification

Homogenization of brain tissues (striatum and SN) was made using protein extraction buffer containing 100 mM Tris HCl (pH 7.4), 750 mM NaCl (sodium chloride), 10 mM EDTA (ethylenediaminetetraacetic acid), 5 mM EGTA (ethylene glycoltetraacetic acid) and a cocktail of protease inhibitors (Roche, Basel, Switzerland) [57 (link)]. The samples were centrifuged at 1,000 g for 10 minutes at 4°C and then supernatant was centrifuged again at 20,000 g for 40 minutes at 4°C to remove the remaining debris. For detecting the levels of inflammatory cytokines, indirect ELISA was done as per the user guide using Milliplex MAP Rat cytokine/chemokine magnetic bead panel kit (RECYTMAG_65K; Millipore; Temecula, CA, USA) and reading was done by LUMINEX MAGPIX® detection system with xPONET software (Millipore Corporation; Billerica, MA, USA). Sensitivity of TNF-α ranges between 1.9 to 156.3 pg/mL, of IL-1β ranges between 2.8 to 2,500.0 pg/mL and of IL-6 ranges between 30.7 to 4,687.5 pg/mL. For detecting the levels of hCDNF and rCDNF, Sandwich enzyme immunoassay was done using separate kits (SEG458Hu and SEG458Ra; Uscn Life Science Inc; Wuhan, Hubei, China) and absorbance was read at 450 nm using a Multiskan® MULTISOFT spectrophotometer (Labsystems; Tokyo, Japan).