测量大鼠死后骨骼肌pH值推断早期死亡时间实验研究

目的利用KNIpHE电极对大鼠死后不同时间骨骼肌pH值进行测定,探讨死后骨骼肌pH值与早期死亡时间(PM I)之间的关系,为利用该种电极在现场快速准确推断死亡时间取得实验依据。方法36只大鼠分为12组,每组3只,分别于死后即刻和死后1,2,3,4,6,8,10,12,16,20,24h取材,制备匀浆后,采用美国Thermo O rion公司210型便携式酸度计配套KNIpHE7120BN电极直接测量pH值;采用南京建成生物工程研究所研制的试剂盒用分光光度法检测乳酸(LA)浓度、肌酸激酶(CK)活性。结果①大鼠死后12h内,股四头肌pH值随PM I延长而逐渐下降,二者之间呈负相关;②大鼠死后12h内,股四头肌LA浓度随PM I延长而上升,与pH值呈负相关;③大鼠死后24h内,股四头肌CK活性随PM I延长而逐渐增强,二者之间呈正相关;④以12h内pH值数据对PM I进行一元线性回归分析,回归方程为:PM I=115.499-17.7pH(R2=0.662,P<0.01,R2为决定系数)。结论利用Thermo O rion KNIpHE电极测定骨骼肌pH值推断早期死亡时间具有较好的应用前景。

Preliminary Study on determining pH value of postmortem skeletal muscle of rat with the Thermo Orion KNIpHE electrode to estimate the early PMI

Objective To determine pH value of skeletal muscle at different time after rat's death with electrode(KNIpHE 7120BN) and to ascertain the relation between pH value of postmortem skeletal muscle and PMI, so as to lay a laboratory foundation for applying the KNIpHEelectrode to determine the time since death. Methods pH value of skeletal muscle was determined with KNIpHE electrode produced by Thermo Orion Company of U.S.A. By using spectrophotometry, LA concentration and CK activity were determined with reagent kit produced by Jiancheng Bioengineer Research Institute of Nanjing. Results ①Within 12 hours after rat's death, pH value of quadriceps femoris decreased with the extension of PMI, which revealed a linear negative correlation .The formula of the relationship between PMI and pH value Within 12 hours was Y=115.499-17.7 X (R~2=(0.662),P<0.01).②Within 12 hours after rat's death, LA concentration in quadriceps femoris rised with the extension of PMI, and it had negative correlation with pH value.③Within 24 hours after rat's death, activity of CK in quadriceps increased as PMI extended. A positive correlation existed between them. Conclusion Applying the KNIpHE electrode to determine the early PMI is of great significance for further researching and application.