Ibayashi S, Fujishima M, Sadoshima S, Yoshida F, Shiokawa O, Ogata J, Omae T
Stroke. 1986 Mar-Apr;17(2):261-6. doi: 10.1161/01.str.17.2.261.
The present study was designed to clarify the effect of blood glucose level on cerebral blood flow and metabolism during and after acute cerebral ischemia induced by bilateral carotid ligation (BCL) in spontaneously hypertensive rats (SHR). Blood glucose levels were varied by intraperitoneal infusion of 50% of glucose (hyperglycemia), insulin with hypertonic saline (hypoglycemia) or hypertonic saline (normoglycemia). Cerebral blood flow (CBF) in the parietal cortex and thalamus was measured by hydrogen clearance technique, and the supratentorial metabolites of the brain frozen in situ were determined by the enzymatic method. In non-ischemic animals, blood glucose levels had no influence on the supratentorial lactate, pyruvate or adenosine triphosphate (ATP) concentrations. In ischemic animals, however, cortical CBF was reduced to less than 1% of the resting value at 3 hours after BCL. However, there were no substantial differences of CBF during and after ischemia among 3 glycemic groups. Cerebral lactate in the ischemic brain greatly increased in hyperglycemia (34.97 +/- 1.29 mmol/kg), moderately in normoglycemia (23.43 +/- 3.13 mmol/kg) and less in hypoglycemia (7.20 +/- 1.54 mmol/kg). In contrast, cerebral ATP decreased in hyperglycemia (0.93 +/- 0.19 mmol/kg) as much as it did in normoglycemia (1.04 +/- 0.25 mmol/kg), while ATP reduction was much greater in hypoglycemia (0.45 +/- 0.05 mmol/kg). At 1-hour recirculation after 3-hour ischemia, ATP tended to increase in all groups of animals, indicating the recovery of energy metabolism. Such metabolic recovery after recirculation was good in hypo- and normoglycemia, and was also evident in hyperglycemia. Our results suggest that hyperglycemia is not necessarily an unfavorable condition in acute incomplete cerebral ischemia.
本研究旨在阐明血糖水平对自发性高血压大鼠（SHR）双侧颈动脉结扎（BCL）诱导的急性脑缺血期间及之后脑血流和代谢的影响。通过腹腔注射50%葡萄糖（高血糖）、胰岛素加高渗盐水（低血糖）或高渗盐水（正常血糖）来改变血糖水平。采用氢清除技术测量顶叶皮质和丘脑的脑血流量（CBF），并通过酶法测定原位冷冻脑的幕上代谢物。在非缺血动物中，血糖水平对幕上乳酸、丙酮酸或三磷酸腺苷（ATP）浓度没有影响。然而，在缺血动物中，BCL后3小时皮质CBF降至静息值的1%以下。然而，3个血糖组在缺血期间及之后的CBF没有实质性差异。缺血脑中的脑乳酸在高血糖组（34.97±1.29 mmol/kg）大幅增加，在正常血糖组（23.43±3.13 mmol/kg）中度增加，在低血糖组（7.20±1.54 mmol/kg）增加较少。相比之下，高血糖组（0.93±0.19 mmol/kg）的脑ATP下降程度与正常血糖组（1.04±0.25 mmol/kg）相同，而低血糖组（0.45±0.05 mmol/kg）的ATP下降幅度更大。缺血3小时后再灌注1小时，所有动物组的ATP均有升高趋势，表明能量代谢有所恢复。再灌注后的这种代谢恢复在低血糖和正常血糖组中良好，在高血糖组中也很明显。我们的结果表明，在急性不完全性脑缺血中，高血糖不一定是不利条件。
