Fig. 6: Met plus Tig promotes pathogens elimination and alleviates inflammatory responses in animal models of infection.

a The experimental protocols for assessing the potentiation of Met to Tig in multiple animal infection models. Created with Biorender.com. b Survival rate in the G. mellonella larvae infected with a lethal dose of E. coli B3-1 (tet(X4)) (1*10⁶ CFU/mL). n = 10 biologically independent animals per group. c Bacterial loads of infected mice lung after Tig treatment, or in combination with Met. The mice were randomly divided into three groups (n = 6 per group), including K. pneumoniae 585-1 (tet(X4)), Tig, Tig + Met groups. Mice were infected with K. pneumoniae 585-1 (tet(X4)) (1*10⁹ CFU/mL, 200 μL per mice, i.p.) and administrated with Met (100 mg/kg) at 1 h after bacterial infection, as well as Tig (20 mg/kg) at 1 h after Met administration, namely at 2 h after bacterial infection. d, e Met and Tig concentrations of mice serum at 6 h post mouse peritonitis infection. Samples were collected from 6 biologically independent mice per group. f Hematoxylin and Eosin (H&E) staining of lung from mice at 6 h post-infection (Scar bar, 100 μm). g Fold changes of inflammatory cytokines between three groups were compared. K. pneumoniae 585-1 (tet(X4)) group was used as the control allowed normalization of the inflammatory data. Pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, INF-γ) were marked with red and anti-inflammatory cytokines (IL-4, IL-10) were marked with blue. Abscissa represents the value after the logarithm of FC (Log₂FC). Lungs samples were collected from 6 biologically independent mice per group. h Relative shifts of major leukocyte populations and platelets compared with the Control, Tig, Tig + Met groups. Baseline cell content in the control group was defined as “5 cells”. Results in Tig, Tig + Met groups were calculated in relative relation to the control group. Detailed results for each group were depicted in Supplementary Fig. 21. Created with Biorender.com. i Photograph the healing process of rat skin wound infection model and the wound areas were calculated on days 0, 5, 10, and 20 among the three groups. n =  6 biologically independent animals per group. Scale bars, 1 cm. The representative wound areas for each group were labeled in the bottom right corner. j Statistical comparison of wound areas in rats of each group on days 0, 5, 10, and 20. Samples were collected from three biologically independent rats per group. k Effects of Tig treatment or Tig plus Met treatment against E. coli B3-1 (tet(X4)) in wound infection model, manifested by the scabs bacterial colonies at 10^th day. l Representative histopathological changes of the wound by H&E staining (left) and Masson staining (right). For Masson staining, the collagen deposition was dyed blue, muscle fibers and cellulose were dyed red. Three biological replicates were performed per group. In d, e, g and j, data are presented as mean values ± SEM. In k, the solid line represents the median, the dotted line represents the quartiles. In b, the P value was determined using a two-sided log-rank (Mantel-Cox) test. In c–e and k, the P values were determined using an unpaired two-tailed Student’s t-test. In j, adjusted P values were determined using two-way ANOVA with Sidak’s multiple comparison test.