Figure 6.

Metformin rescues doxycycline activity in vivo. A) Survival rates of the G. mellonella larvae (n = 10 per group) infected by E. coli B2 (1.0 × 10⁶ CFUs) at the right posterior gastropoda with the treatments of doxycycline (50 mg kg⁻¹) or metformin (50 mg kg⁻¹) alone or in combination (50 + 50 mg kg⁻¹) at left posterior gastropoda (n = 10 per group). p‐values were determined by log‐rank (Mantel‐Cox) test. B) Survival rates of the female BALB/C mice (n = 8 per group) infected by a lethal dose of E. coli B2 (1.0 × 10⁸ CFUs) and treated with a single dose of doxycycline (50 mg kg⁻¹) or metformin (50 mg kg⁻¹) alone or a combination of doxycycline plus metformin (50 + 50 mg kg⁻¹), or PBS as vehicle by intraperitoneal injection. p‐values were determined by log‐rank (Mantel‐Cox) test. C) Bacterial load of infected thigh muscle in neutropenic mice (n = 8 per group) by a nonlethal dose of E. coli B2 or MRSA T144 decreased significantly after a single intraperitoneal combination therapy. p‐values were determined by Mann–Whitney U test.