Section of Forensic Medicine, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy.
Clin Ter. 2024 Jul-Aug;175(Suppl 1(4)):70-74. doi: 10.7417/CT.2024.5089.
The role of forensic pathologists is pivotal in definitively diagnosing drowning cases. Further differentiation becomes essential for distinguishing between freshwater drowning (FWD) and saltwater drowning (SWD). Aquaporins are small integral membrane proteins that serve as major water transport pathways in various cell types. AQP4 appears to be involved in mechanisms related to cerebral volume regulation. Our study aims to examine the expression of AQP4 in the brain as a potential marker for differentiating between FWD and SWD relating to autopsy-performing timing.
A total of 23 cases were classified into three groups: FWD, SWD, and controls. All samples were classified upon autopsy-performing timing into two subgroups: within and after 72 hours of death. The samples were then processed for histological and immunohistochemical investigations.
For autopsies performed within 72 hours of death, we found a significantly higher value of AQP4-positive astrocytes in cases of FWD compared to SWD and control groups. We also found a significantly lower AQP4 expression in SWD cases compared to the control group. For autopsies conducted after 72 hours, the immunohistochemical staining does not reveal the peripheral terminations of astrocytes, which appear blurred and only recognizable as halos. In conclusion, the data aligns with existing literature about autopsies performed within 72 hours. However, in autopsies conducted after 72 hours, uncertain and even opposed results are observed. The difference can be ascribed to the post-mortem transformative processes that take place upon the cessation of vital functions.
法医病理学家在明确诊断溺水案件中起着至关重要的作用。进一步区分淡水溺水（FWD）和海水溺水（SWD）变得至关重要。水通道蛋白是小的整合膜蛋白，作为各种细胞类型中的主要水运输途径。AQP4 似乎参与与脑容量调节相关的机制。我们的研究旨在检查 AQP4 在大脑中的表达，作为区分与尸检执行时间有关的 FWD 和 SWD 的潜在标志物。
总共 23 例病例分为三组：FWD、SWD 和对照组。所有样本均根据尸检执行时间分为两个亚组：死亡后 72 小时内和 72 小时后。然后对样本进行组织学和免疫组织化学研究。
对于在死亡后 72 小时内进行的尸检，我们发现 FWD 病例中 AQP4 阳性星形胶质细胞的阳性率明显高于 SWD 和对照组。我们还发现 SWD 病例的 AQP4 表达明显低于对照组。对于 72 小时后进行的尸检，免疫组织化学染色无法显示星形胶质细胞的外周末端，这些末端显得模糊，只能识别为光环。总之，这些数据与在 72 小时内进行的尸检的现有文献一致。然而，在 72 小时后进行的尸检中，观察到不确定甚至相反的结果。差异可归因于生命功能停止后发生的死后转化过程。
