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.