Neonatal hypoxia–ischemia (HI) is one of the main causes of tissue damage, cell death, and imbalance between neuronal excitation and inhibition and synaptic loss in newborns. GABA, the major inhibitory neurotransmitter of the central nervous system (CNS) in adults, is excitatory at the onset of neurodevelopment and its action depends on the chloride (Cl⁻) cotransporters NKCC1 (imports Cl⁻) and KCC2 (exports Cl⁻) expression. Under basal conditions, the NKCC1/KCC2 ratio decreases over neurodevelopment. Thus, changes in this ratio caused by HI may be related to neurological disorders. The present study evaluated the effects of bumetanide (NKCC cotransporters inhibitor) on HI impairments in two neurodevelopmental periods. Male Wistar rat pups, 3 (PND3) and 11 (PND11) days old, were submitted to the Rice-Vannucci model. Animals were divided into 3 groups: SHAM, HI-SAL, and HI-BUM, considering each age. Bumetanide was administered intraperitoneally at 1, 24, 48, and 72 h after HI. NKCC1, KCC2, PSD-95, and synaptophysin proteins were analyzed after the last injection by western blot. Negative geotaxis, righting reflex, open field, object recognition test, and Morris water maze task were performed to assess neurological reflexes, locomotion, and memory function. Tissue atrophy and cell death were evaluated by histology. Bumetanide prevented neurodevelopmental delay, hyperactivity, and declarative and spatial memory deficits. Furthermore, bumetanide reversed HI-induced brain tissue damage, reduced neuronal death and controlled GABAergic tone, maintained the NKCC1/KCC2 ratio, and synaptogenesis close to normality. Thereby, bumetanide appears to play an important therapeutic role in the CNS, protecting the animals against HI damage and improving functional performance.

新生儿缺氧缺血（HI）是新生儿组织损伤、细胞死亡、神经元兴奋与抑制失衡以及突触丧失的主要原因之一。GABA 是成人中枢神经系统 (CNS) 的主要抑制性神经递质，在神经发育开始时具有兴奋性，其作用取决于氯 (Cl ^- ) 协同转运蛋白 NKCC1（输入 Cl ^-）和 KCC2（输出 Cl ^-）的表达。在基础条件下，NKCC1/KCC2 比率随着神经发育而降低。因此，HI引起的这一比例的变化可能与神经系统疾病有关。本研究评估了布美他尼（NKCC 协同转运蛋白抑制剂）对两个神经发育时期的 HI 损伤的影响。将 3 天 (PND3) 和 11 天 (PND11) 的雄性 Wistar 大鼠幼仔提交给 Rice-Vannucci 模型。考虑到每个年龄，将动物分为 3 组：SHAM、HI-SAL 和 HI-BUM。HI 后 1、24、48 和 72 小时腹腔注射布美他尼。最后一次注射后通过蛋白质印迹分析 NKCC1、KCC2、PSD-95 和突触素蛋白。进行负趋地性、翻正反射、旷场、物体识别测试和莫里斯水迷宫任务来评估神经反射、运动和记忆功能。通过组织学评估组织萎缩和细胞死亡。布美他尼可预防神经发育迟缓、多动以及陈述性和空间记忆缺陷。此外，布美他尼逆转了HI引起的脑组织损伤，减少了神经元死亡并控制了GABA能张力，维持了NKCC1/KCC2比率，并使突触发生接近正常。因此，布美他尼似乎在中枢神经系统中发挥重要的治疗作用，保护动物免受HI损伤并改善功能表现。