Histological Structure Of The Inferior colliculus Of The Midbrain In Rabbit At different Ages

The mammalian inferior colliculus has been a subject of manyhistological and immunohistochemical studies. However, studiesconcerning the development and the age related changes are scarceespecially at the electron microscopic level. So the aim of this work is tostudy the histological structure of the inferior colliculus at different agegroups with a special attention to its ultrastructure.Thirty healthy male rabbits were utilized in this study. They wereclassified into three groups (l0 animals each) according to their ages.Group A: young animals (1-2 weeks).Group B: adult animals (6-9 months)Group C: senile animals (2-3 years)The animals were anathesized using ether inhalation. Their brainswere gently removed from the skull after decapitation. The midbrain at thelevel of the inferior colliculus was processed as a whole for lightmicroscope examination. Some specimens were fixed in Bouin’s fixativefor 24 hours. Sections of 7 urn thick were obtained and stained with H Estain to demonstrate the general structure of the inferior colliculus. Otherwere fixed in Ayoma fixative and processed for silver impregnationtechnique for demonstration of neurons. For electron microscopeexamination, the inferior colliculi were cut into small pieces. Immediatelyfixed in glutaraldehyde and osmium tetroxide and processed to obtainultrathin sections (90 urn).Light microscope examination of the different groups revealed thatthe nerve cells of the inferior colliculus of the young animals werenumerous and had short dendritic processes. Also, there were many glialcells. The neuropil contained many nerve processes and small blood .capillaries.