Diabetes mellitus type 1 induces dark neuron formation in the dentate gyrus: a study by Gallyas' method and transmission electron microscopy

Vol. 52 No. 2, 2011


Sh. Ahmadpour, H. Haghir

Background: Diabetes mellitus type 1 is a chronic endogenous stressor. We investigated the effects of a diabetes mellitus type 1 on dark neuron formation in granular layer of dentate gyrus. Materials and Methods: Diabetes was induced by a single intraperitoneal (IP) injection of streptozotocin (STZ) at a dose of 60 mg/kg dissolved in saline. Control animals were received only saline. In the end of eight weeks, the brains were removed and hippocampi studied by Gallyas' method and transmission electron microscopy. Results: The comparison between the rate of dark neurons in diabetic group (223+/-25) and of control (5.75+/-4.34) showed significant level of difference (p<0.05). Ultrastructurally dark neurons showed apoptotic death criteria namely: dark and electron dense appearance, chromatin condensation, margination and clumping. Conclusions: Present results suggest that STZ-induced diabetes accelerates dark neuron formation with apoptotic criteria in granule layer of dentate gyrus.

Corresponding author: Shahriar Ahmadpour, Assistant Professor, e-mail: shahahmadpour@gmail.com

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