Neuropil Alteration of the Habenula Nucleus in the Experimental Model of Schizophrenia Induced by Ketamine

Background and aim: Neuropil is a densely packed network of glial processes, neuronal processes, extracellular matrix, and microvascular in the central nervous system. The habenula nucleus is one of the brain regions contributing actively to emotional processing and regulating negatively motivated behaviors. This study aimed to examine the neuropil alteration of the habenula nucleus in the experimental model of schizophrenia.Material and methods: Twenty adult Wistar rats were randomly divided into two groups. The experimental group received ketamine at a dose of 10mg/kg intraperitoneally for one week. The control group was treated with saline. At the end of the experiment, animals were deeply anesthetized, the brains were removed, and Paraffin-embedded sections of 10µm thickness were cut on microtome. The randomized sections were stained with H E. The position of the HB was recognized, and the neuropil surface area was measured according to the stereology method.Results: The surface area of the right (9841±1355µm2) and the left (9110±1390.5 µm2) habenula nucleus showed a meaningful difference in comparison with the right (1134±272µm2) and the left (1247±348 µm2) habenula nucleus of the control group (p=0.000). The number of astrocytes in the right HB of the experimental group (440±96.2) and the left HB of the experimental group (422±103.2) showed a meaningful difference in comparison to those of the control group (RHB: 97±31.1 and LHB: 88±9.08) (p=0.000).Conclusions: The results of this study showed that an experimental model of schizophrenia leads to neuropil expansion in the habenula nucleus.