Lactic acidosis in vivo: testing the link between lactate generation and H+ accumulation in ischemic mouse muscle
Lactic acidosis in vivo: testing the link between lactate generation and H+ accumulation in ischemic mouse muscle
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DOI：
10.1152/japplphysiol.01189.2009
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发表时间：
2010-06-01
影响因子：
3.3
通讯作者：
Conley, Kevin E.
中科院分区：
文献类型：
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作者：
Marcinek, David J.;Kushmerick, Martin J.;Conley, Kevin E.
Marcinek DJ，Kushmerick MJ，Conley KE.体内乳酸酸中毒：测试缺血小鼠肌肉中乳酸产生和H+积累之间的联系。J Appl Physiol 108：1479-1486，2010.首次发表于2010年2月4日; doi：10.1152/japplphysiol.01189.2009。乳酸产生和细胞酸中毒之间的联系已被质疑的基础上的H+产生的可能性，独立于在糖酵解过程中的乳酸生产在生理条件下。在这里，我们测试糖酵解H+的产生是否匹配乳酸生产在生理pH值和乳酸范围内使用缺血施加到小鼠的后肢。我们测量了H+生成和ATP水平在体内使用P-31-磁共振波谱和化学测定的细胞内乳酸水平在后肢肌肉。通过化学分析未发现ATP含量的显著变化（P > 0.1），这与通过P-31-磁共振光谱测量的磷酸肌酸的化学计量下降（20.2 +/-1.2mM）相对于Pi的上升（18.7 +/-2.0mM）一致。在25分钟的缺血过程中，发现pH从7.0大幅下降至6.7，乳酸积累至25 mM。H+生成的增加与乳酸的积累密切相关，如与接近同一性的斜率密切相关（0.98; r（2）= 0.86）所示。糖酵解H+生产和乳酸升高之间的这种一致性通过分析体内糖酵解中涉及的潜在反应得到证实，并支持在大幅升高乳酸和降低pH值的条件下乳酸酸中毒的概念。然而，这种联系预计会在耗尽磷酸肌酸的条件下失败，导致净ATP水解和非糖酵解H+生成。因此，直接测量和体内糖酵解的化学计量分析都支持乳酸酸中毒作为肌细胞生理条件的一个可靠概念。
Marcinek DJ, Kushmerick MJ, Conley KE. Lactic acidosis in vivo: testing the link between lactate generation and H+ accumulation in ischemic mouse muscle. J Appl Physiol 108: 1479-1486, 2010. First published February 4, 2010; doi:10.1152/japplphysiol.01189.2009.-The link between lactate generation and cellular acidosis has been questioned based on the possibility of H+ generation, independent of lactate production during glycolysis under physiological conditions. Here we test whether glycolytic H+ generation matches lactate production over a physiological pH and lactate range using ischemia applied to the hindlimb of a mouse. We measured the H+ generation and ATP level in vivo using P-31-magnetic resonance spectroscopy and chemically determined intracellular lactate level in the hindlimb muscles. No significant change was found in ATP content by chemical analysis (P > 0.1), in agreement with the stoichiometric decline in phosphocreatine (20.2 +/- 1.2 mM) vs. rise in P-i (18.7 +/- 2.0 mM), as measured by P-31-magnetic resonance spectroscopy. A substantial drop in pH from 7.0 to 6.7 and lactate accumulation to 25 mM were found during 25 min of ischemia. The rise in H+ generation closely agreed with the accumulation of lactate, as shown by a close correlation with a slope near identity (0.98; r(2) = 0.86). This agreement between glycolytic H+ production and elevation of lactate is confirmed by an analysis of the underlying reactions involved in glycolysis in vivo and supports the concept of lactic acidosis under conditions that substantially elevate lactate and drop pH. However, this link is expected to fail with conditions that deplete phosphocreatine, leading to net ATP hydrolysis and nonglycolytic H+ generation. Thus both direct measurements and an analysis of the stoichiometry of glycolysis in vivo support lactate acidosis as a robust concept for physiological conditions of the muscle cell.