Pyramidal cell morphology and cell death in the hippocampus of adult mice with experimentally induced hydrocephalus

Abstract

Abstract: Background: Hippo-
campus is a neural structure in the

temporal lobe that plays a crucial

role in learning and mem-
ory. Cognitive impairment with

learning disabilities is a common
feature in hydrocephalus and is
more prominent in adult-onset
hydrocephalus. The aim of this

study is to describethe morpho-
logical alterations in the pyrami-
dal cells of the hippocampus of

adult hydrocephalic mice.

Method: Hydrocephalus was in-
duced in adult albino mice by

intra-cisternal injection of kaolin
suspension (250 mg/ml in sterile
water). They were sacrificed 7, 14

and 21 days post-induction. Mor-
phological analysis was carried

out on hematoxylin and eosin- stained coronal sections of the

hippocampus: the pyramidal neu-
rons (normal and pyknotic) in the

CA1 and CA3 subregions were
counted and the pyknotic index
(PI) was calculated. The somatic

and dendritic features of Golgi-
stained pyramidal neurons were

examined by light microscopy in
both hydrocephalic and control
mice.
Result: The PI was significantly
greater in the CA1 region of the
hippocampus in the hydrocephalic
groups compared to the age- matched controls. The dendritic
processes of pyramidal neurons in
the CA1 region were fewer with
shorter terminal branches in the

hydrocephalic mice than in con-
trols; this was pronounced at 7

days post-induction. In the CA3
region, there was no difference in
dendritic arborization between
hydrocephalic and control mice.
Conclusion: Acute adult-onset
hydrocephalus was associated with
increased pyknosis and reduced

dendritic arborization in hippo-
campal pyramidal cells in the CA1

but not CA3 region.

Keywords: Hippocampal pyrami-
dal cell, Hydrocephalus, Pyknotic

index, Golgi stain