2. Methods
We conducted this systematic review and meta-analysis in accordance with the Preferred Reporting of Systematic Reviews and Meta-Analysis (PRISMA statement, Page et al., 2021) and the Cochrane Handbook for Systematic Reviews of Intervention (Higgins et al., 2019). This review was registered in the Open Science Framework (DOI 10.17605/OSF.IO/8C3HT). The review question was formulated according to the acronym PICOS (population, intervention, control, outcomes, and study design): What is the efficacy of Tumor Necrosis Factor-alpha, interleukin-1 beta, and interleukin-6, as in vitro inflammatory trial biomarkers, compared to nitric oxide (gold standard) in LPS inflamed RAW 264.7 cells? (Supplementary Material S1 - Table 2).