Morphological changes caused by aging on skeletal musclesand effects of exercise: a literature review

The main components of the skeletal muscle are myocytes, capillaries and interstitial tissue. Aging affects thesecomponents differently with loss of muscle fibers (sarcopenia) as the most important change since it is theprimary responsible for muscle function decrease with aging. Among non-pharmacological factors that may havea beneficial influence on the effects of aging on the muscle, exercises are the most appropriate. Both resistanceand aerobic exercises have proven to curtail the effects of muscle aging. The aim of this paper is to presenta review of the main morphological changes that aging brings about in muscles and show the importance ofexercising to minimize these changes.

The importance of resveratrol in tissue aging: a review

Some theories point to the relationship between endocrinology and aging, while others support that agingis either linked to the immune system, or related to the thelomeres shortening and free radicals. However,what deserve the attention from the scientific community are the silent regulatory proteins 2 (Sir2). Theseproteins are dependent on Nicotinamide Adenin Dinucleodide (NAD+) and can be activated by either caloricrestriction or by a poliphenol, the resveratrol (3,5,4’-triidroxistilbene), also known as 3,5,4’stilbenetriol.Besides exerting benefits to health as a whole, resveratrol has been demonstrated to promote live extension.The resveratrol bring a diversity of benefits to health because they activate the same metabolic pathways asthose activated by the caloric restriction, demonstrating to be efficient to increase the lifespan. Moreover, itseems that the regulation of the mitochondrial biogenesis by the resveratrol is a potential therapeutic targetto deal with endothelial dysfunction and vascular diseases. In addition resveratrol could act as a prominentactivator of Sirt1 by amplifying the relationship NAD+/NADH, by increasing the expression of PGC-1 andby decreasing the expression of UCP2. A functional analysis of the resveratrol acting over the aging and thelife extension brings up the need for the investigation of multiple tissues by the fact that resveratrol could beassociated with the expression of genes in distinct metabolic functions that could be affected by aging.

Effect of prenatal low-protein diet in subepicardial neuron of rat: a morphological study

Heart autonomic ganglia are known to play an important role in cardiac rhythm control, protecting againstcertain arrhythmias due to their parasympathetic activity. Cardiac disorders may arise following starvingstates during pregnancy; cardiac performance and cardiac fibers have been shown to suffer deleterious effectsunder starvation. Morphology of these plexuses may suffer interference of extrinsic factors, but data is stilllacking about the effects of low protein diet during pregnancy and early postnatal period on subepicardialneuron structure. Two groups of pregnant Wistar rats were submitted to different diets according to itsprotein content, normal and 5% casein, until 21 days after delivery. The offspring was divided in two groups,D and N, according to their motherLs diet, low and normal protein respectively, and then sacrificed. Theatrial neurons were identified by ƒÀ-nicotinamide adenine dinucleotide (NADH) and adenine dinucleotidephosphate diaphorase (NADPH-d) staining. Profile areas of the nerve cell bodies were measured. NADHstaining did not show significant differences between groups but NADPH- d profile areas of nerve cell bodiesfrom group D were smaller than in control group. Ultrastructural changes were observed in group D rats:agglomerated ribosomes, increase in nucleoli density and irregular chromatin.Low-protein diet in rats at earlydevelopmental stages interferes in size, and ultrastructure of subepicardial neurons. Even though underfeedingduring perinatal period did not produce neuronal death, neuron development is delayed and permanentchanges can supervene in long term.

Low protein diet during perinatal period decreasesthe number of subepicardial neurons in rats

Subepicardial plexus of the atria is an interdependent heart control system and its structure and functionmay be influenced by external factors. We studied the influence of protein deprivation on subepicardialneurons at early development stages by subjecting rats to a low protein diet (5% of casein) during pre and postnatal period. Atrial neurons were identified by histochemical methods b-nicotinamide adenine dinucleotide(NADH) reaction, b-nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) reaction andAcetylcholinesterase (AChE) reaction and counted in 21 day-old rats. Besides a significant reduction in bodyand heart weight, the total number of neurons decreased 46% in the undernourished group as compared tocontrol animals. Our data suggest that deficient nutrition during early developmental period may produceirreversible deleterious changes later in life.