α-鹅膏蕈碱在大鼠体内的毒代动力学与组织分布特征

Toxicokinetics and tissue distribution of alpha-amanitin in rats

目的研究α-鹅膏蕈碱在大鼠体内的毒代动力学和组织分布特征。方法SD大鼠ip给予α-鹅膏蕈碱(1.5 mg·kg^(-1)),于给药前和给药后5,10,20,30和45 min及1,1.5,2.5,4和8 h分别采集尾静脉血,采用液相色谱-串联质谱(LC-MS/MS)法测定血液中α-鹅膏蕈碱的浓度,应用DAS 2.0药动学软件,以非房室模型法计算统计矩参数,绘制浓度-时间曲线,拟合毒代动力学参数。依据毒代动力学结果,将18只SD大鼠随机分为3组,分别于给药15和40 min及2.5 h后处死,采集心、肝、脾、肺、肾、全脑、小肠、胃壁和睾丸9种组织样本及左心室动脉血,LC-MS/MS法测定α-鹅膏蕈碱浓度。结果大鼠ip给予α-鹅膏蕈碱后,全血峰浓度(C_(max))为(633±121)μg·L^(-1),消除半衰期(T1/2)为(0.72±0.37)h,达峰时间(T_(max))为(0.52±0.16)h,体内总清除率(CLz)为(1.62±0.26)L·h·kg^(-1),曲线下面积(AUC_(0-t))为(946±183)μg·h·L^(-1),平均滞留时间(MRT0-t)为(1.18±0.17)h,表观分布容积(Vz)为(1.65±0.86)L·kg^(-1)。组织分布研究结果表明,α-鹅膏蕈碱在SD大鼠体内广泛分布,肾中浓度最高,其次是肺、小肠、胃壁、左心室动脉血和肝,心、脾和睾丸等中含量较低,脑中含量极低。α-鹅膏蕈碱吸收消除快,在各组织中15 min即可检出,40 min达峰,2.5 h后浓度低于15 min。结论ip给予α-鹅膏蕈碱在SD大鼠体内吸收消除快,给药后约0.52 h血药浓度达峰值,4 h后不能检出;α-鹅膏蕈碱主要分布在肾,其次为血流丰富的组织及代谢器官,如肺、小肠、胃壁、左心室动脉血和肝等,在心、脾和睾丸等组织含量较低,脑组织含量极低。推测其血脑屏障透过率低,对肾可能具有毒性靶向作用。

OBJECTIVE To study the toxicokinetics and tissue distribution characteristics of alphaamanitin in rats.METHODS The tail venous blood was collected from SD rats before and 5,10,20,30 and 45 min,1,1.5,2.5,4 and 8 h after intraperitoneal injection of alpha-amanitin(1.5 mg·kg^(-1)),and the concentration of alpha-amanitin in blood was determined by liquid chromatography-mass spectrometry(LC-MS/MS).DAS 2.0 software was used to analyze and plot the drug-time curve with toxicokinetic parame⁃ters.Based on the toxicokinetics results,18 SD rats were randomly divided into three groups.The rats were sacrificed,and left ventricular arterial(LVA)blood and 9 types of tissue samples involving the heart,liver,spleen,lung,kidney,whole brain,small intestine,stomach wall and testis were collected 15 min,40 min and 2.5 h after dosing,and the concentrations of alpha-amanitin were measured by LC-MS/MS to obtain the tissue distribution results of alpha-amanitin in SD rats.RESULTS Toxicokinetics studies revealed that the peak blood concentration(C_(max))was(633±121)μg·L^(-1),the elimination half-life(T1/2)was(0.72±0.37)h,and the peak time(T_(max))was(0.52±0.16)h.The total clearance rate(CLz)was(1.62±0.26)L·h·kg^(-1),the area under the curve(AUC_(0-t))was(946±183)μg·h·L^(-1),and the mean reten⁃tion time(MRT0-t)was(1.18±0.17)h.The apparent volume of distribution(Vz)was(1.65±0.86)L·kg^(-1).The results of tissue distribution study showed that alpha-amanitin was widely distributed in SD rats with the highest concentration in the kidney,followed by the lung,small intestines,stomach wall,LVA blood and liver,but was low in the heart,spleen,testicles and other tissues,and very low in the brain.Alpha-amanitin was absorbed and eliminated quickly,peaked at 40 min in each tissue,and the concen⁃tration was minimized after 2.5 h.CONCLUSION The absorption and elimination of alpha-amanitin by intraperitoneal injection are rapid in SD rats,and the blood concentration reaches the peak about 31 min after administration,but can not be detected 4 h later.Alpha-amanitin is mainly distributed in the kidney,followed by the tissues and metabolic organs with rich blood flow,such as the lung,small intestines,stomach wall,LVA blood and liver.The content of alpha-amanitin is low in the heart,spleen,testicles and other tissues,and very low in the brain.It is speculated that it may have toxic targeting effect on the kidney and low blood-brain barrier permeability.