Aasum E, Larsen T S
Faculty of Medicine, University of Tromsø, Tromsø, 9037, Norway.
Cryobiology. 1999 May;38(3):243-9. doi: 10.1006/cryo.1999.2165.
We examined the effect of hypothermia and rewarming on myocardial function and calcium control in Langendorff-perfused hearts from rat and guinea pig. Both rat and guinea pig hearts demonstrated a rise in myocardial calcium ([Ca]total) in response to hypothermic perfusion (40 min, 10 degrees C), which was accompanied by an increase in left ventricular end diastolic pressure (LVEDP). The elevation in [Ca]total was severalfold higher in guinea pig than in rat hearts, reaching 12.9 +/- 0.8 and 3.1 +/- 0.6 micromol.g dry wt-1, respectively. The rise in LVEDP, however, was comparable in the two species: 62.5 +/- 2.5 (guinea pig) and 52.5 +/- 5.1 mm Hg (rat). Following rewarming, [Ca]total remained elevated in guinea pig, whereas a moderate decline in [Ca]total was observed in the rat (13.6 +/- 1.9 and 2.2 +/- 0.3 micromol.g dry wt-1, respectively). Posthypothermic values of LVEDP were also significantly higher in guinea pig compared to rat hearts (42.5 +/- 6.8 vs 20.5 +/- 5.1 mm Hg, P < 0.027). Furthermore, whereas rat hearts demonstrated a 78 +/- 7% recovery of left ventricular developed pressure, there was only a 15 +/- 7% recovery in guinea pig hearts. Measurements of tissue levels of high energy phosphates and glycogen utilization indicated a higher metabolic requirement in guinea pig than in rat hearts in order to oppose the hypothermia-induced calcium load. Thus, we conclude that isolated guinea pig hearts are more sensitive to a hypothermic insult than rat hearts.
我们研究了低温及复温对大鼠和豚鼠Langendorff灌流心脏心肌功能和钙调控的影响。大鼠和豚鼠心脏在低温灌注（40分钟，10摄氏度）时均表现出心肌钙（[Ca]总量）升高，同时左心室舒张末期压力（LVEDP）增加。豚鼠心脏中[Ca]总量的升高幅度比大鼠心脏高几倍，分别达到12.9±0.8和3.1±0.6微摩尔·克干重-1。然而，LVEDP的升高在两个物种中相当：62.5±2.5（豚鼠）和52.5±5.1毫米汞柱（大鼠）。复温后，豚鼠心脏中[Ca]总量仍保持升高，而大鼠心脏中[Ca]总量则出现适度下降（分别为13.6±1.9和2.2±0.3微摩尔·克干重-1）。与大鼠心脏相比，豚鼠心脏低温后的LVEDP值也显著更高（42.5±6.8对20.5±5.1毫米汞柱，P<0.027）。此外，大鼠心脏左心室发展压力恢复了78±7%，而豚鼠心脏仅恢复了15±7%。高能磷酸盐组织水平和糖原利用的测量表明，豚鼠心脏比大鼠心脏需要更高的代谢需求来对抗低温诱导的钙负荷。因此，我们得出结论，离体豚鼠心脏比大鼠心脏对低温损伤更敏感。
