The Developing Left Superior Cervical Ganglion of Pacas(Agouti paca)

Curcumin prevents neuronal loss and structural changes in the superior cervical (sympathetic) ganglion induced by chronic sleep deprivation, in the rat model

Background

In modern societies, sleep deprivation is a serious health problem. This problem could be induced by a variety of reasons, including lifestyle habits or neurological disorders. Chronic sleep deprivation (CSD) could have complex biological consequences, such as changes in neural autonomic control, increased oxidative stress, and inflammatory responses. The superior cervical ganglion (SCG) is an important sympathetic component of the autonomic nervous system. CSD can lead to a wide range of neurological consequences in SCG, which mainly supply innervations to circadian system and other structures. As the active component of Curcuma longa, curcumin possesses many therapeutic properties; including neuroprotective. This study aimed to evaluate the effect of CSD on the SCG histomorphometrical changes and the protective effect of curcumin in preventing these changes.

Methods

Thirty-six male rats were randomly assigned to the control, curcumin, CSD, CSD + curcumin, grid floor control, and grid floor + curcumin groups. The CSD was induced by a modified multiple platform apparatus for 21 days and animals were sacrificed at the end of CSD or treatment, and their SCGs removed for stereological and TUNEL evaluations and also spatial arrangement of neurons in this structure.

Results

Concerning stereological findings, CSD significantly reduced the volume of SCG and its total number of neurons and satellite glial cells in comparison with the control animals (P < 0.05). Treatment of CSD with curcumin prevented these decreases. Furthermore, TUNEL evaluation showed significant apoptosis in the SCG cells in the CSD group, and treatment with curcumin significantly decreased this apoptosis (P < 0.01). This decrease in apoptosis was observed in all control groups that received curcumin. CSD also changed the spatial arrangement of ganglionic neurons into a random pattern, whereas treatment with curcumin preserved its regular pattern.

Conclusions

CSD could potentially induce neuronal loss and structural changes including random spatial distribution in the SCG neurons. Deleterious effects of sleep deprivation could be prevented by the oral administration of curcumin. Furthermore, the consumption of curcumin in a healthy person might lead to a reduction of cell death.

Morphology and Topography of the Celiac Plexus in Degu (Octodon Degus)

Here, we investigate the morphology and topography of the celiac plexus components in degu (Octodon degus). The study was performed using six adult individuals of both sexes. Macromorphological observations were performed using a derivative of the thiocholine method specially adapted for this study type (Gienc, 1977). The classical H&E technique was used for analysis of the cytoarchitectonic of the ganglion, and the AChE (Karnovsky and Roots, 1964) and SPG (De la Torre, 1980) techniques to observe cholinergic and adrenergic activity. The celiac plexus of degu is located on the ventral and lateral surface of the abdominal aorta, at the level where the celiac artery separates from the aorta. This structure consists of two large and two smaller aggregations of neurocytes connected with postganglionic fibers. Histochemical investigations have demonstrated the mainly cholinergic characteristic of the intraganglionic and postganglionic fibers of the celiac plexus, while the adrenergic fibers accompanied only the blood vessels and neurocytes revealed differentiation of adrenergic activity. Histological analysis revealed that neurocytes occupied about half of the cross-section area, with the nerve fibers, connective tissue, and blood vessels forming the remaining part. Ganglionic cells were oval, and usually contained a single nucleus, although two nuclei were sometimes observed.

Stereological and allometric studies on neurons and axo-dendritic synapses in superior cervical ganglia

The superior cervical ganglion (SCG) plays an important role in neuropathies including Horner's syndrome, stroke, and epilepsy. While mammalian SCGs seem to share certain organizational features, they display natural differences related to the animal size and side and the complexity and synaptic coverage of their dendritic arborizations. However, apart from the rat SCG, there is little information concerning the number of SCG neurons and synapses, and the nature of relationships between body weight and the numbers and sizes of neurons and synapses remain uncertain. In the recognition of this gap in the literature, in this chapter, we reviewed the current knowledge on the SCG structure and its remodeling during postnatal development across a plethora of large mammalian species, focusing on exotic rodents and domestic animals. Instrumentally, we present stereology as a state-of-the-art 3D technology to assess the SCG 3D structure unbiasedly and suggest future research directions on this topic.

SCG postnatal remodelling--hypertrophy and neuron number stability--in Spix's yellow-toothed cavies (Galea spixii)

Whilst a fall in neuron numbers seems a common pattern during postnatal development, several authors have nonetheless reported an increase in neuron number, which may be associated with any one of a number of possible processes encapsulating either neurogenesis or late maturation and incomplete differentiation. Recent publications have thus added further fuel to the notion that a postnatal neurogenesis may indeed exist in sympathetic ganglia. In the light of these uncertainties surrounding the effects exerted by postnatal development on the number of superior cervical ganglion (SCG) neurons, we have used state-of-the-art design-based stereology to investigate the quantitative structure of SCG at four distinct timepoints after birth, viz., 1-3 days, 1 month, 12 months and 36 months. The main effects exerted by ageing on the SCG structure were: (i) a 77% increase in ganglion volume; (ii) stability in the total number of the whole population of SCG nerve cells (no change--either increase or decrease) during post-natal development; (iii) a higher proportion of uninucleate neurons to binucleate neurons only in newborn animals; (iv) a 130% increase in the volume of uninucleate cell bodies; and (v) the presence of BrdU positive neurons in animals at all ages. At the time of writing our results support the idea that neurogenesis takes place in the SCG of preás, albeit it warrants confirmation by further markers. We also hypothesise that a portfolio of other mechanisms: cell repair, maturation, differentiation and death may be equally intertwined and implicated in the numerical stability of SCG neurons during postnatal development.

Hypertrophy and neuron loss: structural changes in sheep SCG induced by unilateral sympathectomy

Recently, superior cervical ganglionectomy has been performed to investigate a variety of scientific topics from regulation of intraocular pressure to suppression of lingual tumour growth. Despite these recent advances in our understanding of the functional mechanisms underlying superior cervical ganglion (SCG) growth and development after surgical ablation, there still exists a need for information concerning the quantitative nature of the relationships between the removed SCG and its remaining contralateral ganglion and between the remaining SCG and its modified innervation territory. To this end, using design-based stereological methods, we have investigated the structural changes induced by unilateral ganglionectomy in sheep at three distinct timepoints (2, 7 and 12 weeks) after surgery. The effects of time, and lateral (left-right) differences, were examined by two-way analyses of variance and paired t-tests. Following removal of the left SCG, the main findings were: (i) the remaining right SCG was bigger at shorter survival times, i.e. 74% at 2 weeks, 55% at 7 weeks and no increase by 12 weeks, (ii) by 7 weeks after surgery, the right SCG contained fewer neurons (no decrease at 2 weeks, 6% fewer by 7 weeks and 17% fewer by 12 weeks) and (iii) by 7 weeks, right SCG neurons were also larger and the magnitude of this increase grew substantially with time (no rise at 2 weeks, 77% by 7 weeks and 215% by 12 weeks). Interaction effects between time and ganglionectomy-induced changes were significant for SCG volume and mean perikaryal volume. These findings show that unilateral superior cervical ganglionectomy has profound effects on the contralateral ganglion. For future investigations, it would be interesting to examine the interaction between SCGs and their innervation targets after ganglionectomy. Is the ganglionectomy-induced imbalance between the sizes of innervation territories the milieu in which morphoquantitative changes, particularly changes in perikaryal volume and neuron number, occur? Mechanistically, how would those changes arise? Are there any grounds for believing in a ganglionectomy-triggered SCG cross-innervation and neuroplasticity?

The semi-automatic nucleator

The nucleator is a well-established manual stereological method of estimating mean cell volume from observations on random cell transects through reference points of the cells. In this paper, we present an automated version of the nucleator that uses automatic segmentation of the boundaries of the cell transects. An expert supervises the process. If the segmentation is judged to be satisfactory, an estimate of the cell volume is calculated automatically on the basis of the whole cell transect. In the remaining cases, the expert intervenes and uses the classical nucleator. The resulting estimator is called the semi-automatic nucleator. In this paper, we study the statistical properties of the semi-automatic nucleator. Formulae for the bias and mean square error are derived. The semi-automatic nucleator may have a small bias but will still in most cases be more efficient than the classical nucleator. Procedures for estimating bias and mean square error from a pilot study are provided. The application of the semi-automatic nucleator is illustrated in a study of somatostatin positive inhibitory interneurons which were genetically labelled with green fluorescent protein (GFP). The cells were sampled with an optical disector. The centre of mass in a central cell transect was used as reference point. It is found in this study that the number of cells needed for obtaining, for instance, a 5% precision of the estimate of mean cell volume is 150 and 189 for the semi-automatic and the classical nucleator, respectively. Taking into account that the time spent analysing one cell is shorter for the semi-automatic nucleator than for the classical nucleator, the semi-automatic nucleator is superior to the classical nucleator.