Effect of senescence on the tyrosine hydroxylase and S100B immunoreactivity in the nigrostriatal pathway of the rat.

Senescence is a natural and progressive physiological event that leads to a series of morphophysiological alterations in the organism. The brain is the most vulnerable organ to both structural and functional changes during this process. Dopamine is a key neurotransmitter for the proper functioning of the brain, directly involved in circuitries related with emotions, learning, motivation and reward. One of the main dopamine- producing nuclei is the substantia nigra pars compacta (SNpc), which establish connections with the striatum forming the so-called nigrostriatal pathway. S100B is a calcium binding protein mainly expressed by astrocytes, involved in both intracellular and extracellular processes, and whose expression is increased following injury in the nervous tissue, being a useful marker in altered status of central nervous system. The present study aimed to analyze the impact of senescence on the cells immunoreactive for tyrosine hydroxylase (TH) and S100B along the nigrostriatal pathway of the rat. Our results show an decreased expression of S100B+ cells in SNpc. In addition, there was a significant decrease in TH immunoreactivity in both projection fibers and TH+ cell bodies. In the striatum, a decrease in TH immunoreactivity was also observed, as well as an enlargement of the white matter bundles. Our findings point out that senescence is related to the anatomical and neurochemical changes observed throughout the nigrostriatal pathway.

S100B protein: general characteristics and pathophysiological implications in the Central Nervous System.

BACKGROUND: Calcium-binding proteins are heterogeneous proteins that act binding this ion in specific domains, performing numerous functions. OBJECTIVE: In the present review, we aim to gather principal information about S100B protein in the Central Nervous System (CNS), highlighting its particularities, mapping, functionalities, and consequences on CNS dysfunction. METHODS: The research was carried out by searching Pubmed, Medline, Science Direct, Lilacs, the Cochrane Library, and Web of Science databases using the following descriptors: S100 protein; Central Nervous System; Nervous Lesions, as well as their corresponding terms in Portuguese and Spanish. The terms were first searched separately, then together. RESULTS: Due to its ability to bind with calcium, S100B is involved in the regulation of several intra- and extracellular physiological processes. As well as being multifunctional, this protein can be considered both a "marker" and "signaling" since it is capable of triggering functions of detection of and protection in situations of injury to the CNS. CONCLUSIONS: In-depth studies are necessary to discover the innumerable actions of this protein which are still unknown. It is expected that these can bring varied benefits by elucidating its therapeutic potential in preclinical and clinical situations.

Supplementation with Curcuma longa Reverses Neurotoxic and Behavioral Damage in Models of Alzheimer's Disease: A Systematic Review.

BACKGROUND: The formation of senile plaques and neurofibrillary tangles of the tau protein are the main pathological mechanism of Alzheimer's disease (AD). Current therapies for AD offer discrete benefits to the clinical symptoms and do not prevent the continuing degeneration of neuronal cells. Therefore, novel therapeutic strategies have long been investigated, where curcumin (Curcuma longa) has shown some properties that can prevent the deleterious processes involved in neurodegenerative diseases. OBJECTIVE: The aim of the present work is to review studies that addressed the effects of curcumin in experimental models (in vivo and in vitro) for AD. METHOD: This study is a systematic review conducted between January and June 2017, in which a consultation of scientific articles from indexed periodicals was carried out in Science Direct, United States National Library of Medicine (PubMed), Cochrane Library and Scielo databases, using the following descriptors: "Curcuma longa", "Curcumin" and "Alzheimer's disease". RESULTS: A total of 32 studies were analyzed, which indicated that curcumin supplementation reverses neurotoxic and behavioral damages in both in vivo and in vitro models of AD. CONCLUSION: The administration of curcumin in experimental models seems to be a promising approach in AD, even though it is suggested that additional studies must be conducted using distinct doses and through other routes of administration.

Astragaloside IV Supplementation Promotes A Neuroprotective Effect in Experimental Models of Neurological Disorders: A Systematic Review.

BACKGROUND: Neurological disorders constitute a growing worldwide concern due to the progressive aging of the population and the risky behavior they represent. Herbal medicines have scientific relevance in the treatment of these pathologies. One of these substances, Astragaloside IV (AS-IV), is the main active compound present in the root of Astragalus membranaceus (Fisch.) Bge, a Chinese medicinal herb with neuroprotective properties. OBJECTIVE: In the present study we performed a systematic review that sought to comprehend the neuroprotective effect presented by AS-IV in experimental models of neurological disorders. METHODS: This study is a systematic review, where an electronic search in United States National Library of Medicine (PubMed), Science Direct, Cochrane Library, Scientific Electronic Library Online (SciELO), Scopus, Web of Science, Medline via Proquest and Periodicos Capes databases covering the years between 2007 and 2017, using "Astragaloside IV" and "Neurodegenerative diseases"; "Astragaloside IV" and " Neurological disorders" as reference terms was made. RESULTS: A total of 16 articles were identified, in which the efficacy of AS-IV was described in experimental models of Parkinson's disease, Alzheimer's disease, cerebral ischemia and autoimmune encephalomyelitis, by improving motor deficits and/or neurochemical activity, especially antioxidant systems, reducing inflammation and oxidative stress. CONCLUSION: The findings of the present study indicate that the administration of AS-IV can improve behavioral and neurochemical deficits largely due to its antioxidant, antiapoptotic and antiinflammatory properties, emerging as an alternative therapeutic approach for the treatment of neurological disorders.

Pattern of tyrosine hydroxylase expression during aging of mesolimbic pathway of the rat.

Senescence is a physiological and progressive event that leads to the impairment of normal functions of the organism. The nervous system is one of the most affected systems during aging, presenting both structural and functional alterations associated with a decline in normal brain functions. In the present study we aimed to evaluate the impact of senescence on the mesolimbic pathway (nucleus accumbens - NAc and ventral tegmental area - VTA) of the rat, through immunohistochemistry for tyrosine hydroxylase (TH) enzyme, in young (3 months old), middle-aged (10 months old) and aged animals (18 months old). There was a significant decrease in the TH-immunoreactivity across NAc in aged animals as compared to the young and middle-aged ones, as revealed by optical densitometry. Medium and caudal regions of the VTA in the young animals possessed a higher number of TH-immunoreactive neurons as compared to the more aged groups. Comparisons among VTA regions in young animals revealed a difference in the number of cell bodies when the medium region was compared to the rostral and caudal regions whilst in both the middle-aged and aged groups comparisons between rostral vs caudal and medium vs caudal regions were significant. Our results show that aging impacts the mesolimbic pathway across its rostrocaudal axis, with a decrease of TH-reactivity in NAc and loss of neurons in VTA. These events may be involved with behavioral alterations observed throughout aging.