Novel Technique for Extraction of the Hippocampus of Adult Male Wistar Rats

The hippocampus is one of the most widely studied areas in the brain because of its remarkable neuronal cell plasticity, functional role in memory processing and learning, and its involvement in some neurodegenerative diseases. Despite being one of the most studied areas in the brain, it is not easily accessible in experimental animals' such as mice and rats. Techniques available for dissection are capital intensive and may not be possible in low income countries. This study described a novel technique for the extraction of the hippocampus. Three apparently healthy adult Wistar rats were used for this study. They were euthanized under anaesthetic condition with ketamine (75 mg/kg). Afterwards they were perfused with formosaline, the skull opened, and the brain harvested. A midline incision was made and the halves of the brain were separated. The medial surface of the halved cerebral hemisphere was faced upward then the cerebrum was dissected and the hippocampus neatly and manually harvested, weighed, grossly observed and histologically processed. Morphologically, the hippocampus is banana-shaped in the Wistar rat, while histologically it revealed normal cytoarchitectural arrangement. Using the manual extraction method, the hippocampus was isolated without distortion, indicating that hippocampus sample can be prepared. Hence, this convenient and accurate dissection technique can be used for histologic, histochemical, immunohistochemical and histopathological study of the hippocampus, especially in low income countries.

Key Words: Wistar rats, hippocampus, dissection, extraction, histologic