Abstract:

Bumetanide is a widely used diuretic in the clinic. In the acute stage of cerebral ischemia, bumetanide can reduce brain edema through the blood-brain barrier, decrease infarct size, and has a protective effect on the brain. However, no relevant studies concerned neuroprotection and nerve regeneration in the chronic stage of cerebral ischemia. This study sought to explore the effects of bumetanide on neurogenesis in the dentate gyrus of the rat hippocampus after the acute stage of cerebral ischemia. Adult Wistar rats weighing 200–250 g were randomly divided into four groups: (1) sham operation group (SHAM group), (2) sham operation + bumetanide group (SHAM + BUM group), (3) ischemia group (ISC group), and (4) ischemia + bumetanide group (ISC + BUM group). Models of cerebral ischemia were established by intracranial injection of endothelin-1. 1 week later, bumetanide was given in the skull using an osmotic pump for 3 weeks, 20 mg/kg per day. Morris water maze was used to assess learning and memory abilities in rats. Immumofluorescence method was utilized to observe DCX-positive cells in the dentate gyrus of the rat hippocampus. By confocal microscopy, series layer in the direction of Z-axis of DCX-positive cells in the dentate gyrus was obtained, and three-dimensional reconstruction was carried out in newborn dendrites and axons. NIH ImageJ software was then applied to track and measure dendrites, axons and their branches. Bumetanide promoted regeneration of neural stem cells and dendrite development in the hippocampal dentate gyrus after cerebral ischemia.

Wangshu Xu and Xuan Sun contributed equally to this work.

Key words: cerebral ischemia, bumetanide, neurogenesis, NKCCl, functional recovery