大鼠急性氧中毒后全脑细胞能量代谢的活体^(31)P磁共振谱研究

31P Nuclear magnetic resonance spectroscopy studies on global cerebral cellular energy metabolism following acute oxygen poisoning in rats

目的：探讨大鼠急性氧中毒后脑的能量代谢产物与脑细胞内 ｐＨ变化的规律。方法：采用磁共振方法，用 ４． ７ Ｔ动物磁共振谱仪，检测氧中毒后不同时程各种磷酸化合物与无机磷酸根（Ｐｉ）、磷酸肌酸（ＰＣｒ）与 γ－ＡＴＰ以及β－ＡＴＰ与Ｐｉ之间的比值，并根据Ｐｉ的化学位移推算脑细胞内ｐＨ值。结果：氧中毒组动物出舱１和３ ｈ后ＰＣｒ／Ｐｉ，ＰＣｒ／γ－ＡＴＰ以及β－ＡＴＰ／Ｐｉ值均显著降低；５ ｈ后恢复正常；２４和 ４８ ｈ后这些比值又降低，而且比早期降低更明显；７２ ｈ后恢复到正常水平。细胞内ｐＨ值在动物出舱后 １和 ３ ｈ出现显著降低；５ ｈ后恢复正常；２４ ｈ后，细胞内 ｐＨ明显升高；４８ ｈ后恢复正常。结论：氧中毒后大脑出现能量代谢障碍及细胞内酸碱代谢紊乱。

Objective: To evaluate cerebral cellular energy metabolism and pH in the rat global cerebral cellular following acute oxygen poisoning. Methods: All ~31P NMR spectra were performed on a high-field, 4. 7 T, NMR spectroscopic imag- ing system using a ~31P/1~H double-tuned surface coil. Intracellular pH were determined according to the spectra of pi. Results: Phosphocreatine to inorganic phosphate (PCr/Pi ), PCr to gamma adenosine triphosphate (PCr/γ-ATP ) and adenosine triphosphate to inorganic phosphate (β-ATP/Pi) decreased compared with the corresponding ratios in control group in the en- tire brain at 1 and 3 h after exposing HBO. At 5 h, no significant decrease of the ratios was found. At 24 h, the ratios were decreased significantly again. At 72 h, the ratios prestored to normal level. Intracellular pH was significantly decreased at 1 and 3 h after exposing HBO. At 5 h, no significant change of the intracellular pH was found. At 24 h, the pH was increased significantly. At 48 h, the pH restored to normal level. Conclusion: There are energy failure and intracellular acidosis and alkalosis in cerebral cellular after oxygen poisoning in rats.