The functional role of brain-derived neurotrophic factor (BDNF) is enhanced following cerebral ischemic injury providing neurons with an important self-protection mechanism in early stage ischemia/hypoxia.OBJECTIVE:
To investigate the expression pattern of BDNF in different rat hippocampal regions following focal cerebral ischemic injury.DESIGN, TIME AND SETTING:
We performed a comparative and neurobiological study of animals in the Department of Histology and Embryology and the Central Laboratory, Hebei Medical University from March to December 2003.MATERIALS:
Forty healthy Sprague Dawley rats were randomly divided into a cerebral ischemia group and a sham operation group, with 20 rats per group.METHODS:
In the cerebral ischemia group, we occluded the right middle cerebral artery with a suture, threading it to a depth of 17–19 mm. In the sham operation group, the threading depth was approximately 10 mm.MAIN OUTCOME MEASURES:
We analyzed the expression of BDNF in different hippocampal regions by immunohistochemical staining of brain sections taken on post-operative days 7, 14, 21 and 30.RESULTS:
Sham operation group: We observed a number of a few BDNF-positive cells with light staining in the hippocampal CA1-CA4 regions and dentate gyrus. Cerebral ischemia group: compared with the sham operation group, BDNF increased on day 7, significantly increased on day 14, and reached a peak on day 21 (P < 0.05). Furthermore, immunologically reactive products were darkly stained, and neurons had long axons. BDNF was particularly highly expressed in the hippocampal CA3 and CA4 regions and dentate gyrus.CONCLUSION:
Cerebral ischemic injury can damage hippocampal neurons. Neurons can increase their anti-ischemic capacity by increasing BDNF expression in the hippocampal CA3 and CA4 regions and dentate gyrus.