Mn porphyrins can ameliorate venous blood gases in TS mice in vivo. TS mice were treated for 28 days, except on weekends, with 1 subcutaneous dose per day of vehicle (n = 10), 0.1 mg/kg MnBuOE (n = 8), or 1 mg/kg MnE (n = 7). i-STAT analysis of the collected blood revealed that venous blood gases could be improved by Mn porphyrins. (A) pH values were somewhat affected with the Mn porphyrins. The levels of pCO₂ (B), pO₂ (C), BEecf (D), HCO₃^– (E), TCO2 (F), and sO₂ (G) increased to some degree in TS mice treated with 0.1 mg/kg MnBuOE and became close to or within the normal ranges in mice treated with 1 mg/kg MnE. (H) Lactate levels significantly decreased in TS mice treated with 0.1 mg/kg MnBuOE and 1 mg/kg MnE. Data are presented as SEM. *P < .05 compared with vehicle treatment.