2.4. RNA Isolation and cDNA Synthesis
Total RNA from blood neutrophils was isolated and purified using the RNeasy Mini Kit with an on-column DNAse-I digest (Qiagen, Hilden, Germany), to avoid genomic DNA contamination. The quality of RNA was analyzed with an Experion™ automated electrophoresis system (Bio-Rad, Hercules, CA, USA), using standard sense RNA analysis LabChips, according to manufacturer’s instructions. The quality of tested RNA samples was determined by the RNA quality index (RQI), which ranged between 7.5 and 10 on a scale from 0–10. cDNA was synthesized from 300 ng total RNA using iScript cDNA Synthesis Kit (Bio-Rad, Hercules, CA, USA), following the manufacturer’s recommendations.