Fig. 4

Chronic exposure to alternative tobacco product aerosols modulated pulmonary proinflammatory cytokine and chemokine levels. Levels of inflammatory cytokines and chemokines in the BAL (A–M) of mice were measured at end of the 8-week exposure to air, EC, HTP or CC aerosols using MILLIPLEX MAP Kit as described previously [47] and in detail in Additional file 1: supplemental methods. Data are presented as bar diagrams with mean ± SE. Non-parametric Kruskal–Wallis test with FDR correction for multiple comparison was performed to see if significant differences exist between groups using GraphPad Prism V.9 (GraphPad; La Jolla, California, USA). Difference between two groups is considered significant at p < 0.05 and indicated with symbols *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001. For each exposure condition, n = 10 animals for air (5M + 5F) and n = 20 animals for EC, HTP, and CC (10M + 10F) per group