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. 2021 Nov 18;12:757417. doi: 10.3389/fphar.2021.757417

FIGURE 5.

FIGURE 5

Systemic CO gas administration significantly blocked LPS-induced depressive and anxiety-like behaviors. (A) LPS (0.83 mg/kg, 0.2 ml/mouse, i.p.) was administered on the last day of the 3-day-adaptation period, while CO gas (0.1, 0.3 ml, i.p.) was administered 30 min before LPS injection and each behavioral test. CO gas treatment increased time spent in the center (B) and total distance (C) as compared to the LPS injection group in the OFT. In the NSF test, LPS treatment increased feeding latency (D) but not total food intake (E). CO gas treatment significantly reversed the depressant-like state induced by LPS, reflected by the increased sucrose preference (F) but no change in total water intake (G) in the SPT. Increased floating time reversed by CO gas (H) and decreased floating latency (I) induced by LPS in the FST. In the TST, CO gas treatment significantly reversed the increased immobility time (J) induced by LPS but not latency to immobility (K). The data are expressed as mean ± SEM and were analyzed with separate one-way ANOVAs. *p < 0.05, **p < 0.001 as compared to the Sal + Sal group; # p < 0.05, ## p < 0.01, ### p < 0.001 as compared to the Sal + LPS group; Sal, saline. LPS, lipopolysaccharide; OFT, open field test; NSF, novelty-suppressed feeding; SPT, sucrose preference test; FST, forced swimming test; TST, tail suspension test (n = 8–9 per group).