First Department of Forensic Science, National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
Department of Forensic Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan.
Int J Legal Med. 2024 Jul;138(4):1245-1254. doi: 10.1007/s00414-024-03199-y. Epub 2024 Feb 27.
In sexual assault cases, it is crucial to discriminate between peripheral blood and menstrual blood to provide evidence for vaginal intercourse with traumatic injury. In this study, the menstrual blood mRNA markers progestagen-associated endometrial protein (PAEP), matrix metallopeptidase 7 (MMP7), and left-right determination factor 2 (LEFTY2) were evaluated by quantitative RT-PCR (RT-qPCR) for the discrimination of menstrual blood from peripheral blood and vaginal fluid. As a result, all markers with cutoff delta cycle quantification (ΔCq) values were specifically determined in menstrual blood among forensically relevant body fluids. Even though the changes in the expression levels of each marker differed during the menstrual cycle, all markers were determined to be positive in most of the randomly collected menstrual blood samples that were analyzed. Additionally, the markers with proposed cutoff ΔCq values could discriminate between menstrual blood and peripheral blood-mixed vaginal fluid samples. The determination of positive markers was less affected by storage temperature under dry conditions than under wet conditions, while PAEP was detectable in samples stored below room temperature under wet conditions. The detectability of PAEP was considered to be the result of its higher expression level compared with MMP7 and LEFTY2. In conclusion, menstrual blood markers for the RT-qPCR procedure evaluated in this study were highly specific for menstrual blood. The proposed procedure could be useful for discriminating between menstruation and traumatic bleeding in the female genital tract. In particular, PAEP is expected to be applicable to forensic casework samples because of its high specificity and robustness.
在性侵犯案件中，区分外周血和月经血对于提供阴道性交伴有创伤性损伤的证据至关重要。在这项研究中，通过定量 RT-PCR（RT-qPCR）评估了月经血 mRNA 标志物孕激素相关子宫内膜蛋白（PAEP）、基质金属蛋白酶 7（MMP7）和左右决定因子 2（LEFTY2），以区分月经血、外周血和阴道液。结果，所有具有截止循环量化（ΔCq）值的标记物都在法医相关体液中的月经血中特异性确定。尽管每个标记物的表达水平在月经周期中有所变化，但在分析的大多数随机收集的月经血样本中，所有标记物均被确定为阳性。此外，具有建议截止 ΔCq 值的标记物可以区分月经血和外周血混合的阴道液样本。在干燥条件下，阳性标记物的确定受储存温度的影响小于在潮湿条件下，而 PAEP 可在潮湿条件下储存于室温以下的样本中检测到。PAEP 的可检测性被认为是其与 MMP7 和 LEFTY2 相比更高的表达水平的结果。总之，本研究中评估的 RT-qPCR 程序的月经血标记物对月经血具有高度特异性。所提出的程序可用于区分女性生殖道的月经和创伤性出血。特别是，由于其高特异性和稳健性，PAEP 有望适用于法医案例样本。
