Morphological changes in the suprachiasmatic nucleus of aging female marmosets (Callithrix jacchus).

Rovena Clara G J Engelberth,Jeferson S Cavalcante,Miriam Stela M O Costa,Jose Ronaldo Dos Santos,Elaine Cristina Gavioli,Carolina V De M Azevedo,Joacil Germano Soares,Kayo Diogenes De A Silva,Expedito S Nascimento Junior,Judney C Cavalcante

doi:10.1155/2014/243825

Abstract

The suprachiasmatic nuclei (SCN) are pointed to as the mammals central circadian pacemaker. Aged animals show internal time disruption possibly caused by morphological and neurochemical changes in SCN components. Some studies reported changes of neuronal cells and neuroglia in the SCN of rats and nonhuman primates during aging. The effects of senescence on morphological aspects in SCN are important for understanding some alterations in biological rhythms expression. Therefore, our aim was to perform a comparative study of the morphological aspects of SCN in adult and aged female marmoset. Morphometric analysis of SCN was performed using Nissl staining, NeuN-IR, GFAP-IR, and CB-IR. A significant decrease in the SCN cells staining with Nissl, NeuN, and CB were observed in aged female marmosets compared to adults, while a significant increase in glial cells was found in aged marmosets, thus suggesting compensatory process due to neuronal loss evoked by aging.

Highlights

The suprachiasmatic nuclei (SCN) are a pair of neurons located in the anterior hypothalamus above the optic chiasma, [1, 2] and it is constituted of about 8,000 to 10,000 neurons [3,4,5]
In SCN sections Nissl-stained (Figures 1(a) and 1(a󸀠)), or marked to neuronal nuclear protein (NeuN)-IR (Figures 1(b) and 1(b󸀠)) and CB-IR (Figures 1(c) and 1(c󸀠)), a decrease in the number of cells was observed in aged marmosets when compared with adult animals
Mann-Whitney test revealed a significant decrease in the number of cells in the SCN stained by Nissl technique in aged compared to adult marmosets (adult marmoset: 110.0 (133.37–87.81); aged marmoset: 51.8 (55.62–49.64); data are represented as median; P = 0.0209; Figure 2(a)) and NeuN (adult marmoset: 92.8 (108.06–75.12); aged marmoset: 37.4 (42.68–32.5); data are represented as median; P = 0.0294; Figure 2(b))

Summary

Introduction

The suprachiasmatic nuclei (SCN) are a pair of neurons located in the anterior hypothalamus above the optic chiasma, [1, 2] and it is constituted of about 8,000 to 10,000 neurons [3,4,5]. Since the 1970’s, the SCN has been considered the central pacemaker [6, 7] that controls physiological and behavioral rhythmic oscillations in mammals [8]. 10% of SCN neurons express VIP in the core subdivision, while around 20% (which means about 2,100 neurons) of SCN in the shell part express VP [9]. Besides VIP and VP, have been described in terminals and perikarya in the SCN, such as neuropeptide Y [10,11,12], 5-HT [13] and calbindin (CB) [10]. Aging process alters structural complexity of the central nervous system, resulting in neurotransmitters alterations [16], atrophy of total gray matter [17], and soma size and dendrites [18]

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