Age-related changes in the articular cartilage of the mandible of rats.

This study investigated the effects of aging on the articular cartilage of the mandible. Wistar rats were divided in two groups (n = 10/per group): 3-months-old group (young group); and 13-months-old group (aged group). After euthanasia, the head of the mandible was collected and stained with hematoxylin and eosin (HE) to evaluate the thickness of the articular layer and cartilage. Sections stained with Picrosirius red and Safranin O were used to evaluate the collagen and proteoglycans deposition, respectively. First, aging has decreased the articular layer thickness. Second, the results suggest a decrease of chondrocytes followed by an increase of the matrix to maintain the mandible homeostasis. Finally, both collagen and proteoglycans increased with aging. Aging displayed important effects to the mandible of aged rats.

Ultrastructural effects of diabetes in the right atrium cardiomyocytes of elderly Wistar rats

The present study aimed to evaluate the effects of diabetes on quantitative parameters of right atrial cardiomyocytes of elderly rats. Wistar rats (14-mo of age) were divided into two groups: streptozotocin-diabetic rats (DG); and control rats (CG). The groups were sacrificed at 16 months. Ultrafine sections of the right atrium were analyzed by electron microscopy. In elderly diabetic animals, histograms of the frequency distribution of natriuretic peptides according to their size showed increased number of small and medium peptides in relation to large peptides, which increased its numerical density leading to a decrease in the mean diameter of both natriuretic peptides. However, elderly diabetic animals remained normotensive. No significant difference was observed between the groups for the volume density of mitochondria, endoplasmic reticulum and Golgi apparatus. In conclusion, elderly diabetic rats showed increased functional activity of atrial cardiomyocytes with greater production of natriuretic peptides in association with a quantitative maintenance of cytoplasmic components. (AU)

Meta-analysis about Atrial Natriuretic Peptide (ANP)

Among the topics studied in physiology and aging, a hormone has been drawing attention from the scientificcommunity: the Atrial Natriuretic Peptide (ANP). The ANP, which is produced by the cardiac atria, hasdemonstrated decisive action in endocrine mechanisms of action inhibiting sodium reabsorption in nephrons,revealing a direct influence on physiological mechanisms linked to aging and chronic stress.The overall objectiveof this study was to assess and analyze scientific literature on the ANP in the Pubmed database from 2010 to2012. 30 articles were collected, verifying authorship and gender division of species, instruments and typesof research. The results showed that the research of multiple authorship appeared mostly with 99.1%, being51.8% of male authorship, 17.9% of female authorship and 29.5% of publications not identified. Researchwith only one author appears with 0.8% in total. As the types of species used, it was observed 50.3% of theworks with humans, 40% with animals and 6.7% mixed (animal / human). As to the instruments used, thebiochemical markers were the ones that stood out, with 30%, followed by label arterial pressure with 12, 2%,drugs, with 11.1% and microscopic studies with 10%. In the typology of research, biochemical research appearsfirst, with 33.3%, followed by research morphophysiological/biochemical research, with 30%, Physiological/ biochemical, with 26.7%, Physiological with 6.7% and Morphophysiological with 3.3%. We can concludethat the publications about the hormone ANP are still little explored when the focus is aging. In the analyzedpublications, there is important information about the physiological and biochemical role of ANP as well ason their molecular composition.

Effects of protein deprivation and refeeding on the subepicardial neurons of rat: subepicardial neurons and low-protein diet

Heart autonomic ganglia play an important role in cardiac rhythm control, protecting against certainarrhythmias due to their parasympathetic activity. Starvation during pregnancy may cause cardiac disorders andhinder optimal cardiac performance. Also, morphology of subepicardial neuron is subjected to the influenceof extrinsic factors. We studied the influence of protein deprivation on subepicardic neurons in rats at earlydevelopment stages and the effect of restoration of a normal diet.: Three groups of pregnant Wistar rats weresubmitted to different diets according to its protein content: normal (NN group) and 5% casein (DD group),until 42 days after delivery and low protein for 21 days with refeeding for a further 21 days (RN group).All animal were weighed. The number and area of neuronal profiles were measured. The neurons werestained by histochemical methods â-nicotinamide adenine dinucleotide (NADH) and â-nicotinamide adeninedinucleotide phosphate diaphorase (NADPH-d) and their ultra structure were observed.Group DD and RNanimals weighed less than those from group NN. The number of neurons and the cellular profile area didnot show significant differences among groups for both techniques. Endoplasmatic reticulum ribosomes inneurons of undernourished animals showed decreased electron density. Protein deprivation in early stages ofdevelopment produces ultra structural changes but does not alter the number and profile area of nerve cellbodies in rats.

Effects of exercise on the morphology of the myenteric neurons of the duodenum of Wistar rats during the ageing process.

This study aimed to evaluate the effects of regular physical activity on the morphology of the myenteric plexus of the duodenum in rats during the ageing process. To this end, 45 Wistar rats were divided into three groups: C (sedentary - 6 months old), S (sedentary - 12 months old) and T (trained - 12 months old). The animals of group S were given with a physical activity programme consisting of a 10-min-treadmill workout once a week. The animals of group T were submitted to the physical activity programme five times a week. Their duodenums were collected and submitted to the techniques of nicotinamide adenine dinucleotide (NADH)-diaphorase enzyme histochemistry for whole-mount preparations and transmission electron microscopy. No differences in the constitution of the myenteric plexuses were found when the sedentary and trained groups were compared with the control group. The ultrastructural features were similar for the three groups. However, it was verified that the physical activity of the trained animals resulted in a similar myenteric neuron morphology to that of the adult animals (6 months old), thereby confirming its beneficial effect, as the sedentary animals had larger alterations in the collagen fibrils and the basal membrane that occur through ageing. The quantitative analysis showed that the NADH-diaphorase positive neurons decreased with ageing and increased with physical activity (P > 0.05). No significant alteration (P > 0.05) in the neuronal profile area of the NADH-diaphorase positive neurons has been observed with ageing.

Diabetes mellitus-related morphoquantitative changes in the celiac ganglion neurons of the dog.

Diabetes mellitus is the most common endocrine disturbance of domestic carnivores and can cause autonomic neurological disorders, although these are still poorly understood in veterinary medicine. There is little information available on the quantitative adaptation mechanisms of the sympathetic ganglia during diabetes mellitus in domestic mammals. By combining morphometric methods and NADPH-diaphorase staining (as a possible marker for nitric oxide producing neurons), type I diabetes mellitus-related morphoquantitative changes were investigated in the celiac ganglion neurons in dogs. Twelve left celiac ganglia from adult female German shepherd dogs were examined: six ganglia were from non-diabetic and six from diabetic subjects. Consistent hypertrophy of the ganglia was noted in diabetic animals with increase of 55% in length, 53% in width, and 61.5% in thickness. The ordinary microstructure of the ganglia was modified leading to an uneven distribution of the ganglionic units and a more evident distribution of axon fascicles. In contrast to non-diabetic dogs, there was a lack of NADPH-diaphorase perikarial labelling in the celiac ganglion neurons of diabetic animals. The morphometric study showed that both the neuronal and nuclear sizes were significantly larger in diabetic dogs (1.3 and 1.39 times, respectively). The profile density and area fraction of NADPH-diaphorase-reactive celiac ganglion neurons were significantly larger (1.35 and 1.48 times, respectively) in non-diabetic dogs compared to NADPH-diaphorase-non-reactive celiac ganglion neurons in diabetic dogs. Although this study suggests that diabetic neuropathy is associated with neuronal hypertrophy, controversy remains over the possibility of ongoing neuronal loss and the functional interrelationship between them. It is unclear whether neuronal hypertrophy could be a compensation mechanism for a putative neuronal loss during the diabetes mellitus.

Trypanosoma cruzi: preliminary investigation of NADH-positive and somatostatin-immunoreactive neurons in the myenteric plexus of the mouse colon during the infection.

In this paper, the distribution of NADH-positive and somatostatin (SOM) immunoreactive neurons in the myenteric plexus of the colon of mice infected with Trypanosoma cruzi was studied. Ten young, male, BALB/c mice were inoculated with the Y strain of T. cruzi, 60 days previously (chronic phase of the infection). Another 10 mice were uninfected controls. Distal and proximal colonic neurons from five chronically infected mice and their controls were stained using the NADH-diaphorase method. Quantitative results showed a significant decrease of 39% in the number of neurons in the proximal colon of infected mice and 58% in the distal colon (p<0.05). SOM was localized in five animals from each group by light microscopy, using an indirect immunofluorescence technique. It was observed that there were far fewer nerve cells and fibres and less intensely stained neuron bodies and varicose SOM-positive nerve fibres in both, control and chronic infected mice. These findings could be related to the disturbances in intestinal motility observed in patients in the chronic phase of Chagas' disease.

Extrinsic cardiac nerve segments in the domestic dog (Canis familiaris- Linnaeus, 1758). Comparative study in young and adult dogs.

In this paper, important connections between the two main contingents of the autonomic nervous system, intrinsic and extrinsic visceral plexus were analysed. Concerning heart innervation, the territories of extrinsic innervation are very important in the treatment of congenital or acquired cardiopathy, thoracic neoplasia and aortic arch persistence, among others. This research compared young and adult extrinsic cardiac innervation and described the surgical anatomic nerve segments. Animals were perfused with a 10% formaldehyde solution in PBS (0.1 m) (pH 7.4) and submitted to macro- and meso-scopic dissection immersed in 60% acetic acid alcoholic solution and 20% hydrogen peroxide aqueous solution. The nerve segments were assigned as: right vagus nerve segment, left vagus nerve segment, right middle cervical ganglion segment, left middle cervical ganglion segment, right caudal laryngeal nerve segment, left caudal laryngeal nerve segment, right phrenic nerve segment and left phrenic nerve segment.

Gross anatomic organization of the capybara's (Hydrochaeris hydrochaeris) brachial plexus.

The innervation of the capybara thoracic limb was characterized. The following nerves were observed constituting the right and left brachial plexus: n. dorsalis scapulae (C4 and C5; C4, C5 and C6) which innervates the m. serratus ventralis cervicis and m. rhomboideus; n. suprascapularis (C4, C5 and C6; C5, C6 and C7) supplying the m. supraspinatus and the m. infraspinatus; cranial and caudal nn. subscapulares (C5 and C6; C5, C6 and C7) innervating the m. subscapularis; n. axillaris (C5 and C6; C6, C7 and C8) which supplies the m. triceps brachii (caput mediale); n. radialis (C6, C7, C8 and T1; C6, C7 and C8) which innervates the m. triceps brachii (caput longum and caput mediale) and the m. extensor carpi radialis, m. extensor digitorum communis, m. extensor digitorum lateralis; n. medianus joined to the n. musculocutaneus (C6, C7, C8 and T1; C6, C7 and C8) supplying the m. biceps brachii, m. flexor carpi radialis and m. coracobrachialis; n. ulnaris (C6, C7, C8 and T1; C6, C7 and C8) leading to the m. flexor carpi radialis, the m. flexor carpi ulnaris and the m. flexor digitorum superficialis; n. thoracodorsalis (C6, C7, C8 and T1; C6, C7 and C8) supplying the m. latissimus dorsi; n. thoracicus lateralis (C8, T1; C7, C8, T1) which innervates m. pectoralis profundus (caudal portion); n. thoracicus longus (C6, C7; C7, C8) which is distributed to the m. serratus ventralis thoracis. A communication between the n. radialis and n. ulnaris was observed at the left brachial plexus.

Cardiac denervation in mice infected with Trypanosoma cruzi.

The neuronal features of the hearts of mice that were acutely or chronically infected with the Y strain of Trypanosoma cruzi were compared with those of control hearts from uninfected mice. Whole-mount preparations of the murine atria, isolated by microdissection, were stained to reveal neurons with NADH-diaphorase activity. Counts, by a microscopist who was blind to the infection status of the donor mouse, revealed that there were significantly (38%) fewer such neurons in the atria from the acutely infected mice than in the atria from the control hearts. The ganglia of the infected mice were also irregularly distributed, severely damaged ganglia being found beside slightly degenerated or morphologically normal ones. Although the ganglia contained small, medium and large neurons, the apparent destruction caused by T. cruzi was confined to the large ones. As neuron counts in preparations of hearts from mice with chronic infections were 32% lower than those in the control hearts, there appears to be no additional loss of cardiac neurons as the acute infection in mice progresses to the chronic phase.

Structure and ultrastructure of the celiac-mesenteric ganglion complex in the domestic dog (Canis familiaris).

A number of neurons of the autonomic nervous system are situated in the ganglia and can be systematically divided into pre-vertebrals, paravertebrals, intramural and para-viscerals. The celiac-mesenteric ganglion, an important pre-vertebral ganglion, is located together with the abdominal aorta and links the central nervous system to the peripheral system, participating in the coordination of peripheral reflexes and principally innervating the stomach, intestines, accessory glands (liver and pancreas). In addition, the celiac-mesenteric ganglion also contributes to the innervation of the spleen and has a role in gastrointestinal motility control. This study examined the structural and ultrastructural aspects of 40 celiac-mesenteric ganglia from domestic dogs. For light microscopy ganglia were included in paraplast and stained with haematoxylin-eosin, picrosirius, toluidine blue, Calleja's and Masson's trichrome. For examination by electron microscopy, the ganglia were submitted to cryofracture, enzyme digestion, hydrolysis and fixed in 5% glutaraldehyde in 0.1 M phosphate buffer (pH 7.4). The celiac-mesenteric ganglion was observed as a ganglionic complex composed of various ganglionic units separated by types I and III collagen fibres, predominantly unmyelinated nerve fibres and continuous capillaries. This complex is surrounded by a double-layer capsule (internal and external). The principal ganglion cells had eccentric nuclei with two nucleoli, the nucleolemma was double and presented nuclear pores. In the cytoplasm there were vesicles of the Golgi apparatus, electron-dense vacuoles, mitochondrias, smooth and granulated endoplasmic reticulum and free ribosomes. In conclusion, this ganglionic complex, in contrast to similar structures in the enteric nervous system, presents separate ganglionic units in a systematic arrangement related to the extrinsic and specific innervation of the target organs.

Aging of myocardial collagen.

The objective of this article was to present a review of the collagen tissue of the heart muscle as a function of age. The myocardial collagen matrix consists of a network of fibrillar collagen which is intimately connected to the myocyte. Most collagen fibers reside in parallel with myocytes. These fibers may have a wavy, taut or coiled appearance. Fibrillar collagen types I and III are the major components of the myocardial collagen matrix. Collagen type I has been found to represent nearly 80% of the total collagen protein, while type III collagen is present in lower proportions (approximately 11%). Cardiac fibroblasts are the cellular source of fibrillar collagen, cardiac myocytes expressing only mRNA for type IV collagen. Collagens types I and III exhibit a high tensile strength which plays an important role in the behavior of the ventricle during the cardiac cycle. The collagen concentration and the intermolecular cross-linking of collagen increase with age. Measurements of collagen content in myocardial tissue suggest that it is the type I collagen fibers that increase in number and thickness in the aged. At the same time, electron microscopic observations have shown an increase in the number of collagen fibrils with a large diameter in the aging heart. The mechanism responsible for the myocardial fibrosis in the senescent myocardium is unclear. The collagen deposition in the myocardium could be due to the regulation of collagen biosynthesis at pre-translational levels. It is possible that the regulatory elements involved in this process are growth factors such as TGF-beta 1 and hormones and neurotransmitters. Details of regulatory mechanism that may come into play during aging may be elucidated by further investigations. The accumulation of collagen within the myocardium increases muscle stiffness. Myocardial function is affected by this process; this is usually reflected by incomplete relaxation during early diastolic filling, and presumably account for the decrease in early left ventricular diastolic compliance.

Dietary sodium intake induced myenteric neuron hypertrophy in Wistar rats.

In the present study we investigated the effect of salt intake on myenteric neuron size of the colon of adult male Wistar rats. The animals were placed on either a high-salt (HS; 8%; 12 animals) or a low-salt diet (LS; 0.15%; 12 animals) for 15 or 52 weeks and blood pressure was measured. The sizes of myenteric neurons of the distal colon from both groups were measured. No difference in neuron size was observed between the HS and LS groups after 15 weeks. After 52 weeks on HS, neuron size was increased (P<0.005) when compared with the LS group. The rats also presented hypertension, which was significantly different at 52 weeks (142 +/- 11 vs 119 +/- 7 mmHg). These results suggest that a long time on an HS diet can significantly increase myenteric nerve cell size.

Dietary sodium intake induced myenteric neuron hypertrophy in Wistar rats

In the present study we investigated the effect of salt intake on myenteric neuron size of the colon of adult male Wistar rats. The animals were placed on either a high-salt (HS; 8 percent; 12 animals) or a low-salt diet (LS; 0.15 percent; 12 animals) for 15 or 52 weeks and blood pressure was measured. The sizes of myenteric neurons of the distal colon from both groups were measured. No difference in neuron size was observed between the HS and LS groups after 15 weeks. After 52 weeks on HS, neuron size was increased (P<0.005) when compared with the LS group. The rats also presented hypertension, which was significantly different at 52 weeks (142 +/- 11 vs 119 +/- 7 mmHg). These results suggest that a long time on an HS diet can significantly increase myenteric nerve cell size.

Fall in the number of intracardiac neurons in aging rats.

The neurons of whole cardiac atria were stained using a NADH-diaphorase technique in young adult (3 months old) (GI) and aging rats (20 months old) (GII). Light microscopy revealed differences in the appearance of the neurons in the two groups. In GI, most ganglia contained 50-100 neurons while in GII, most ganglia usually contained 20 neurons. The mean total number of neurons in the atria of GII was 245+/-31, i.e. only 23% of the mean value in GI (1086+/-203). The mean size of the ganglionic neurons (area of maximum cell profile) was 702 microm2 in GI and 1065 microm2 in GII. Histological sections of the ganglia revealed that a capsule of collagen fibers sheaths each ganglion in both groups. In GII, the density of collagen fibers increases in the capsule and in the septa within the ganglia; yellow or red, type I collagen fibers predominate in this group. No elastic fibers were present in the cardiac ganglia of either group. It is suggested that in aging rats, structural changes and reorganization of the remnant neurons accompany neuron reduction.

Vasoactive-intestinal-peptide- and substance-P-immunoreactive nerve fibres in the myenteric plexus of mouse colon during the chronic phase of Trypanosoma cruzi infection.

The distribution of a tachykinin (substance P) and vasoactive intestinal peptide (VIP) and the number and morphology of the large granular vesicles (LGV) in the myenteric plexus of the colons of mice were investigated. Six of the 12 young, male, Swiss mice studied had been inoculated with the Y strain of Trypanosoma cruzi 2 months previously whereas the others were uninfected controls. Substance P (SP) and VIP were localized by light microscopy, using an immunohistochemical method, and LGV were counted in sections studied by electron microscopy. There were far fewer LGV and less intensely staining varicose VIP- and SP-positive nerve fibres in the infected mice than in the controls. Denervation of the myenteric plexus may decrease the content of tachykinins (TK) and VIP in animals infected with T. cruzi. Such reduction in TK and VIP activity could be related to the disturbances in intestinal motility observed in the chronic phase of Chagas disease.

Morphometry and acetylcholinesterase activity of the myenteric neurons of the mouse colon in the chronic phase of experimental Trypanosoma cruzi infection.

The myenteric plexus of the proximal colon, midcolon, and distal colon was studied in mice chronically infected with the Y strain of Trypanosoma cruzi by means of histochemical methods for NADH-diaphorase and acetylcholinesterase (AChE) on whole mount preparations. Ganglia of infected mice displayed an irregular distribution, with neurons severely altered in form and were found side by side with slightly degenerated or morphologically normal ones. Significant reductions of at least 36% in the numbers of neurons were recorded in all regions of the colons of infected animals, especially in the distal colon where the neuron number decreased by more than 44%. Measurements of neuron size suggest that the neuronal destruction caused by T. cruzi affected the medium and large neurons. The small neurons apparently were not affected by the infection. The histochemical demonstration of AChE by the direct coloring copper ferrocyanide method showed that in the control animals, most of the neurons of the plexus displayed AChE activity in the cytoplasm although the neurons showed different reaction intensities. The AChE activity was also present, but at a lower intensity, in the myenteric plexus of the colons of infected animals. These results suggest that the T. cruzi infection affects some categories of neurons and implies that some particular enteric neurotransmitter systems could be affected and the potency of their action upon intestinal function consequently reduced.

A morpho-quantitative study of the myenteric ganglia throughout the human digestive tract.

We have examined the sizes of nerve cells present in the myenteric plexus in the human esophagus, stomach, duodenum and sigmoid colon using a nonhistochemical method (Giemsa) in laminar preparations of the muscularis externa. The collagen and elastic system related fibers in the myenteric ganglia were also qualitatively evaluated. The major mean of perikaryal area was observed in the esophagus (489.97 micron 2 +/- 212.35 micron 2) and the minor in the sigmoid colon (241.64 micron 2 +/- 122.62 micron 2). There were no significant differences between the mean areas of the myenteric neurons in the stomach (284.77 micron 2 +/- 134.70 micron 2) and in the duodenum (291.39 micron 2 +/- 157.86 micron 2). In all regions a ganglionic capsule of collagen fibers with thin septa surrounding isolated or grouped neurons was observed. The elastic and elastic-related fibers (elaunin and oxytalan fibers) were also present in both the ganglionic capsule and inside the ganglia. There were no differences among the regions. These data suggest that factors such as size of nerve cells and structural aspects of the ganglionic capsule are not related with the incidence of megaesophagus and megacolon.