Cytoarchitecture of greater cane rat (Thryonomys swinderianus) habenulae and mammillary body

Abstract

This study was conducted to investigate expression of neurons, glia and connective tissue markers in the habenulae and mammillary body of the Greater  Cane Rat (GCR) using histological and immunohistochemical techniques. Four apparently healthy males GCR obtained from Lagos Nigeria were used for  this experiment. The brains were harvested after perfusion, carefully dissected and post-fixed in 10% neutral-buffered-formalin (NBF) at 40C for 48 hours.  Subsequently, tissue sections were prepared and stained using Haematoxylin and Eosin (H&E), Cresyl-violet, ionized calcium-binding-adapter  molecule 1 (Iba1; microglia), glial fibrillary acidic protein (GFAP; astrocytes), neuronal nuclei (NeuN; neurons) and collagen type 1 (Collagen1) antibodies.  H&E and Cresyl-violet staining showed the neuronal nuclei and their fibres in the habenulae, mammillary body, and pial capsule that surround the  mammillary body ventrally. Astrocytes in the habenulae showed positive immunoreaction to anti-GFAP while the mammillary body revealed expression of  perivascular astrocytes and capsular astrocytes. Also, in the mammillary body, the perivascular microglia and meningeal microglia in the pial capsule  showed immunopositive reaction to anti-Iba1 while the fibres within blood vessels and capsule were immunopositive to collagen type 1 antibody in the  same structure. This work has provided the first cytoarchitectural features and clear description of expression of these specific markers in habenulae and  mammillary body in the GCR, which are similar to other rodents but with slight variations.