Figure 7

Protection efficacy in bacterial infection mice models. (A) Survival of mice. Mice were infected intraperitoneally with MRSA ATCC43300 (1 × 10¹⁰ CFU) and treated intraperitoneally with DLP2, DLP4, and vancomycin at 2 h and 12 h after post-infection, respectively. Survival of mice was recorded for seven days. (B) Effect of peptides on splenic and nephritic bacterial burdens in S. aureus-infected mice. Mice were infected intraperitoneally with MRSA ATCC43300 (8 × 10⁹ CFU) and treated with a single dose of DLP2, DLP4 (7.5 mg/kg), and vancomycin (10 mg/kg) at 2 h post infection, respectively. Kidneys and spleens were removed at 3 h post-treatment to analyze bacterial translocation. Data are expressed as mean ± standard deviation. ^*p < 0.05; ^**p < 0.01; ^***p < 0.001. Statistical significance of differences between experimental groups of animals was determined using the one-way ANOVA and Tukey multiple comparison. Data points represent the number of CFU from the indicated organ of individual mice; horizontal bars indicate the mean CFU values for each group. (C–E) Effects of DLP2 and DLP4 on sera cytokines and organ injury. Mice were infected intraperitoneally with MRSA ATCC43300 (8 × 10⁹ CFU) and treated with DLP2, DLP4 (7.5 mg/kg), and vancomycin (10 mg/kg). Sera were collected and cytokines were detected at 3 and 16 h after treatment, respectively. Lungs and spleens were harvested and detected at 1 d, 3 d and 5 d post-infection. Statistical analysis was performed using the one-way ANOVA and Bonferroni multiple comparison. ^**p < 0.01; ^***p < 0.001. Vancomycin and PBS served as positive and negative controls for all experiments. (C) Sera TNF-α, IL-6, IL-10, GM-CSF, and MCP-1 levels. (D) Lung tissues. (E) Spleen tissues. (D,E) CK1: the infected mice without treatment; CK2: the uninfected mice.