大鼠骨骼肌新鲜度指标与早期死亡时间关系

目的计算不同时间大鼠骨骼肌新鲜度指标(K值、K₁值、K₀值、H值、P值、G值和IMP比例)变化规律,研究其与早期PMI的关系,筛选出最优评价指标,用于早期PMI推断。方法SD大鼠处死后,保存在20℃恒温条件下,于死后即刻(0h)、4h、8h、16h、24h、32h和48h提取大鼠双后腿骨骼肌,利用高效液相色谱仪测定ATP相关代谢产物(ATP,ADP,AMP,IMP,Ino,Hx),计算其肌肉组织的K值、K1值、K0值、H值、P值、G值和IMP比例,并建立与PMI关系的相关回归方程。结果随PMI推移,IMP比例呈现下降趋势,K值、K₁值、K₀值、P值、G值和H值逐渐增加。7种新鲜度指标均可用于早期PMI推断(R²=0.922-0.971,P<0.01),其中H值与PMI相关系数最高、曲线拟合关系最好(R²=0.971)。结论测定尸体肌肉组织新鲜度指标有望成为法医实践中PMI推断的有效方法,其H值为最优早期PMI推断指标。

Relationship between indicators of skeletal muscle freshness and early postmortem interval in rats under constant temperature

Objective To calculate the variation of skeletal muscle freshness indexes(K value, K₁ value, K₀ value, H value, P value, G value and IMP ratio) in rats at different PMIs, study the relationship was studied between them and early PMI, so as to screen out the optimal evaluation indexes for early PMI estimation. Methods SD rats were killed and stored at 20℃. The skeletal muscles of both hind legs of rats were extracted at immediately(0 h), 4 h, 8 h, 16 h, 24 h, 32 h and 48 h after death. The ATP-related metabolites(ATP, ADP, AMP, IMP, Ino, Hx) were determined by high performance liquid chromatograph(HPLC). The K value, K₁ value, K₀ value, H value, P value, G value and IMP ratio of muscle tissue were calculated, and the correlation regression equation with PMI was established. Results Over PMI, IMP ratio showed a downward trend, K value, K1 value, K0 value, P value, G value and H value increased gradually, and seven freshness indexes could be used for early PMI inference(R²=0.922-0.971, all P<0.01), in which H value had the highest correlation coefficient with PMI and the best curve fitting relationship(R²=0.971). Conclusion Determinatioin of cadaveric muscle tissue freshness index is expected to be an effective method for PMI estimation in forensic practice, and H value is the best early PMI estimation index.