Astolphi Rafael Dias, de Seixas Alves Maria Teresa, Evison Martin Paul, Francisco Raffaela Arrabaça, Guimarães Marco Aurelio, Iwamura Edna Sadayo Miazato
Department of Pathology, Escola Paulista de Medicina - Universidade Federal de São Paulo, São Paulo, SP, Brazil.
Northumbria University, Newcastle Upon Tyne, United Kingdom.
Forensic Sci Int. 2019 May;298:384-392. doi: 10.1016/j.forsciint.2019.03.008. Epub 2019 Mar 14.
Human bone histological analysis is a useful tool to assess post mortem diagenesis and to predict successful nuclear DNA typing of forensic material. This study is part of a series of studies developed by the authors intended to improve the understanding of post mortem diagenesis and to develop applications for DNA analysis of skeletal species from tropical soils, in order to optimize genetic and anthropological protocols. The aim of this study was to analyze the impact of burial period on the integrity of exhumed compact bone microstructure from tropical climate. In fragments of exhumed human femora from 39 individuals from the same cemetery (exhumed group) and 5 fresh femora from routine autopsies (control group), sections stained by hematoxylin-eosin were analyzed in order to measure bone microstructural integrity. We found that bone integrity index in exhumed group was negatively influenced by the period of burial (r = -0.37, p < 0.05) and highly significantly decreased (p < 0.0001) in comparison to control group. The period of burial and nitric acid decalcification time was positively correlated (r = 0.51; p < 0.01), leading to imply a bone petrification process during inhumation. Exhumed group showed higher level of matrix bone loss (p < 0.001), as expected, and 87% of cases analyzed were "tunneled" as described by Hackett. Bone integrity index and bone matrix tend to decrease in bones buried in tropical soil between 8-14 years of inhumation. This period is short if we consider cases in which there are preserved bones interred for longer periods in other environments. These data must be considered in cases where genetic identification of exhumed skeletons from tropical environment is required. The diagenesis in these bones and the variations of results found are discussed, clarifying some challenges for forensic laboratories, especially in DNA analysis.
人类骨骼组织学分析是评估死后成岩作用以及预测法医材料核DNA分型能否成功的有用工具。本研究是作者开展的一系列研究的一部分，旨在增进对死后成岩作用的理解，并开发针对热带土壤中骨骼物种DNA分析的应用，以优化遗传学和人类学研究方案。本研究的目的是分析埋葬时间对热带气候下挖掘出的致密骨微观结构完整性的影响。对来自同一墓地的39具挖掘出的人类股骨碎片（挖掘组）和5具常规尸检的新鲜股骨（对照组）进行苏木精-伊红染色切片分析，以测量骨微观结构的完整性。我们发现，挖掘组的骨完整性指数受埋葬时间的负面影响（r = -0.37，p < 0.05），与对照组相比显著降低（p < 0.0001）。埋葬时间与硝酸脱钙时间呈正相关（r = 0.51；p < 0.01），这意味着入土过程中存在骨石化过程。正如预期的那样，挖掘组显示出更高水平的基质骨丢失（p < 0.001），并且87%的分析病例呈现出哈克特所描述的“隧道状”。埋葬在热带土壤中8至14年的骨骼，其骨完整性指数和骨基质往往会下降。如果考虑到在其他环境中埋葬时间更长但骨骼仍得以保存的情况，这段时间是较短的。在需要对热带环境中挖掘出的骨骼进行基因鉴定的案例中，必须考虑这些数据。本文讨论了这些骨骼中的成岩作用以及所发现结果的差异，阐明了法医实验室面临的一些挑战，尤其是在DNA分析方面。
