Measurement of oxygen consumption by murine tissues in vitro

Introduction: A novel in vitro system was developed to measure O 2 consumption by murine tissues over several hours. Methods: Tissue specimens (7-35 mg) excised from male Balb/c mice were immediately immersed in ice-cold Krebs-Henseleit buffer, saturated with 95% O 2 :5% CO 2 . The specimens were incubated at 37°C in the buffer, continuously gassed with O 2 :CO 2 (95:5). . Results: NaCN inhibited O 2 consumption, confirming oxidation occurred in the mitochondrial respiratory chain. The rate of respiration in lung specimens incubated in vitro for 3.9 ≤ t ≤ 12.4 h was 0.24±0.03 μM O 2 min −1 mg −1 (mean±SD, n=28). The corresponding rate for the liver was 0.27±0.13 (n=11, t≤4.7 h), spleen 0.28± 0.07 (n=10, t≤5 h), kidney 0.34±0.12 (n=7, t≤5 h) and pancreas 0.35±0.09 (n=10, t≤4 h). Normal tissue histology at hour 5 was confirmed by light and electron microscopy. There was negligible number of apoptotic cells by caspase 3 staining. Discussion: This approach allows accurate assessment of tissue bioenergetics in vitro