Fig. 10
High concentration of CO2 enhances the expression of IL-1β in hypoxic BV-2 microglia (n = 4). a The immunoreactive bands of IL-1β (17 kDa) and GAPDH (36 kDa). b There is a significant interaction effect between 15% CO2 treatment and 0.2% O2 treatment (P < 0.05). c Simple effects analyses show that the protein expression of IL-1β in HC group has no significant difference compared with Control group (ns P > 0.05). The protein expression levels in hypoxia group are significantly increased compared with control group (**P < 0.01). Hypoxia + HC group had the highest levels of the protein in comparison with HC group (**P < 0.01) and hypoxia group (** P < 0.01). The protein expression of IL-1β is significantly suppressed with the treatment of 10 μM Z-YVAD-FMK (**P < 0.01). d Immunofluorescence images show the expression of IL-1β (B, E, H, K, red), lectin+ microglia (A, D, G, J, green), and the co-localization of IL-1β and microglia (C, F, I, L). The results also show that high concentration of CO2 (15% CO2) alone is not enough to increase the expression of IL-1β. The expression of IL-1β in hypoxia-activated BV-2 microglia is markedly increased. Additionally, the expression of IL-1β is further enhanced following treatment of 15% CO2 in the hypoxic BV-2 microglia. Scale bars: (A-L), 20 μm. ns non-significant, IL-1β interleukin-1 beta, HC group high concentration of carbon dioxide group