Fig. 1
From: All-trans retinoic acid increases the pathogenicity of the H9N2 influenza virus in mice
Effects of the H9N2 virus on body weight (a), food intake (b), and survival (c) of mice. Body weight is presented as mean of the rate of weight change (%) ± SD. Rate of weight change (%) = daily weight/initial weight × 100%. n = 10–11. Food intake is presented as mean of the change rate of food intake (%) ± SD. Change rate of food intake (%) = food intake per day/initial food intake × 100%. n = 10–11. Survival rate (%) = the number of mice alive/total number of mice observed. n = 20. Mice that lost more than 30% of their original body weight were euthanized and considered dead on that day. *P < 0.05, **P < 0.01, analyzed with one-way ANOVA or the log-rank test. Blank, mice receiving sterile PBS inoculation and cottonseed oil injection at 0–9 days after inoculation; H9N2, mice receiving H9N2 virus (105 TCID50) inoculation and cottonseed oil injection at 0–9 days after inoculation. ATRA, all-trans retinoic acid; TCID50, median tissue culture infective dose