Sodium Nitrite-induced Hypoxic Injury in Rat Hippocampus

Objective: To explore the effect of sodium nitrite-induced hypoxia on the hippocampus and the dentate gyrus in adult rats. Methodology: Adult male albino rats, weighing 180-200 gm were divided into two groups and treated as follows: Group I: served as control and received normal saline, Group II: served as hypoxic rats and received sodium nitrite (75 mg/kg) subcutaneously. One hour after sodium nitrite injection, rats were decapitated. The brains were removed and placed overnight in fixative containing 10% formalin. These were paraffinembedded for hematoxylin and eosin staining and cut at 5 μ in the coronal plane. Sections passing through bregma level -2.8 to -3.3 mm were used to count the neurons in the CA1, CA2, CA3, and CA4 subsectors and the dentate gyrus. Round, clear and medium or large neurons with distinct nucleus were counted. Cells with darkly stained shrunken nuclei and cells with fragmented nuclei were excluded from the