牛磺酸调节缺氧性肺、脑血管反应的机理研究

MECHANISMS OF THEMODULATOR EFFECT OF TAURINE ON HYPOXYPOXIC RESPONSES OF PULMONARY AND CEREBRAL BLOOD VESSELS

本实验从磷脂酶Ａ＿２（ＰＬＡ＿２）、前列腺素（ＰＧｓ）、白三烯（ＬＴｓ）和过氧化脂质（ＬＰＯ）方面探讨了牛磺酸调节肺、脑血管对急、慢性缺氧反应的机制。急性缺氧时狗出肺与出脑血中ＬＰＯ增加，ＰＬＡ，活性有升高趋势，但出脑与出肺（入脑）血相比无显著性差异。出肺与出脑血中ＬＴＣ＿４、ＴＸＢ＿２、６－Ｋｅｔｏ－ＰＧＦ＿（１ａ）及ＴＸＢ＿２／６－Ｋｅｔｏ－ＰＧＦ＿（１ａ）比值均升高。慢性缺氧大鼠肺、脑组织中ＰＬＡ＿２活性均升高。牛磺酸增加缺氧时６－Ｋｅｔｏ－ＰＧＦ＿（１ａ），减弱其它变化。提示牛磺酸对缺氧性肺缩血管反应的调节作用可能与降低缺氧时ＰＬＡ＿２活性，抑制脂质过氧化和ＬＴＣ＿４、ＴＸＡ＿２生成，降低ＴＸＡ＿２／ＰＧＩ＿２比值有关；而牛磺酸减弱缺氧性脑舒血管反应不是直接通过上述变化起作用的。

The mechanisms of the modulator effects of taurine on responses of pdmonary and cerebralblood vessels to acute and chronic hypoxia were explored in dogs and rats.It was found that inacute hypoxic dogs,the LPO content in outflow blood from the lung and from the brain in-creased.There were no signiflcant differences in PLA,activitV and LPO content between thecerebral outflow blood and inflow blood.The levels of LTC_4,TXB_2,6-Keto-PGF_(1α) and the ra-tio of TXB_2 to 6-Keto-PGF_(1α) in outflow blood from lung and from brain increased.In chronichypoxic rats,the PLA_2 activity of lung and brain tissue increased.Taurine can attenuate all thechanges during hypoxia mentioned above except 6-Keto-PGF1a.The study suggests that de-creasing the PLA_2 activity inhibiting lipid peroxidation and the synthesis of LTC_4 and TXA_2,reducing the TXA/PGI_2 rtitio during hypoxia might be responsible for the pulmonaryvasodilator effect of taurine.The effect of taurine on hypoxic cerebral vasodilation might not bedirectly related to these changes.