Aquaporin 4 (AQP4) is the main membrane water channel in the brain involved in regulating water homeostasis. The water distribution in neural tissue is often dysregulated after hypoxic neural injury. Previous research has indicated that victims of sudden infant death syndrome (SIDS) and sudden unexplained death in childhood (SUDC) have an underlying brain dysfunction that impairs their critical arousal response to hypoxic stress during sleep. The aim of this study was to determine the expression levels of AQP4 in the hippocampus in SIDS/SUDC cases and controls, and compare the findings with AQP4 genotypes that previously have been shown to be associated with SIDS. Immunochemical staining and morphometry were used to evaluate the density of AQP4-positive astrocytes in 30 SIDS/SUDC cases and 26 controls. AQP4-positive cells were counted in grids covering three layers in the hippocampus, which revealed that their count in any of the layers did not differ significantly between cases and controls. A decline in AQP4 expression was observed for infants older than 12 weeks. The AQP4 expression was lower in infants and children with the rs2075575 CT/TT genotype than in those with the CC genotype. This study indicates that AQP4 expression may be influenced by both age and genotype in infants. The role of AQP4 in the pathogenesis of SIDS remains to be elucidated.

水通道蛋白 4 (AQP4) 是大脑中参与调节水稳态的主要膜水通道。缺氧性神经损伤后，神经组织中的水分分布经常失调。先前的研究表明，婴儿猝死综合征 (SIDS) 和儿童期不明原因猝死 (SUDC) 的受害者有潜在的脑功能障碍，这会损害他们在睡眠期间对缺氧压力的关键唤醒反应。本研究的目的是确定 SIDS/SUDC 病例和对照组海马中 AQP4 的表达水平，并将研究结果与先前已证明与 SIDS 相关的 AQP4 基因型进行比较。免疫化学染色和形态计量学用于评估 30 例 SIDS/SUDC 病例和 26 例对照中 AQP4 阳性星形胶质细胞的密度。在覆盖海马三层的网格中对 AQP4 阳性细胞进行计数，这表明它们在任何一层的计数在病例和对照之间没有显着差异。对于 12 周以上的婴儿，观察到 AQP4 表达下降。rs2075575 CT/TT基因型婴儿和儿童的AQP4表达低于CC基因型婴儿和儿童。该研究表明 AQP4 的表达可能受婴儿年龄和基因型的影响。AQP4 在 SIDS 发病机制中的作用仍有待阐明。rs2075575 CT/TT基因型婴儿和儿童的AQP4表达低于CC基因型婴儿和儿童。该研究表明 AQP4 的表达可能受婴儿年龄和基因型的影响。AQP4 在 SIDS 发病机制中的作用仍有待阐明。rs2075575 CT/TT基因型婴儿和儿童的AQP4表达低于CC基因型婴儿和儿童。该研究表明 AQP4 的表达可能受婴儿年龄和基因型的影响。AQP4 在 SIDS 发病机制中的作用仍有待阐明。