Mitochondria influence glycolytic and tricarboxylic acid cycle metabolism under postmortem simulating conditions

Abstract

The purpose of this study was to test mitochondrial functionality under conditions simulating postmortem metabolism. Isolated mitochondria from porcine longissimus lumborum (LLM) and masseter (MM) muscles were incorporated into an in vitro model that mimics postmortem metabolism. pH and ¹³C-enrichment of glycolytic and tricarboxylic acid (TCA) cycle intermediates were evaluated at 0, 15, 30, 120, 240, and 1440 min. Addition of mitochondria to the in vitro model lowered its pH at 240 min compared with control. Reactions containing mitochondria had lower pyruvate and lactate [M + 2] and [M + 3] isotopomers at 240 and 1440 min than controls. Furthermore, LLM lowered the enrichment of [M + 2], [M + 3], and [M + 4]α-ketoglutarate at 1440 min compared with MM and control. Succinate [M + 2] and [M + 3] were greater in MM than the control and LLM. [M + 3]fumarate was greater in control at 240 and 1440 min than LLM and MM treatments. Our data indicated that mitochondria are capable of mobilizing pyruvate generated though glycolysis under conditions simulating muscle postmortem metabolism.

Keywords: Glycolysis; Isotope tracer; Mitochondria; TCA cycle.