Accumulation of alpha-synuclein (α-syn) is central to the pathogenesis of Parkinson's disease (PD). Previous studies suggest that α-syn pathology may originate from the olfactory bulb (OB) or gut in response to an unknown pathogen and later progress to the different brain regions. Aging is viewed as the utmost threat to PD development. Therefore, studies depicting the role of age in α-syn accumulation and its progression in PD are important. In the present study, we gave intranasal rotenone microemulsion for 6 weeks in 12-month-old female BALB/c mice and found olfactory dysfunction after 4 and 6 weeks of rotenone administration. Interestingly, motor impairment was observed only after 6 weeks. The animals were sacrificed after 6 weeks to perform western blotting and immunohistochemical studies to detect α-syn pathology, neuroinflammation and neurodegeneration. We found α-syn accumulation in OB, striatum, substantia nigra (SN) and cortex. Importantly, we found significant glial cell activation and neurodegeneration in all the analysed regions which were absent in our previous published studies with 3 months old mice even after they were exposed to rotenone for 9 weeks indicating age is a crucial factor for α-syn induced neuroinflammation and neurodegeneration. We also observed increased iron accumulation in SN of rotenone-exposed aged mice. Moreover, inflammaging was observed in OB and striatum of 12-month-old BALB/c mice as compared to 3-month-old BALB/c mice. In conclusion, there is a difference in sensitivity between adult and aged mice in the development and progression of α-syn pathology and subsequent neurodegeneration, for which inflammaging might be the crucial probable mechanism.

• MeSH
• alfa-synuklein * metabolismus   MeSH
• dopamin MeSH
• dopaminergní neurony metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• mozek metabolismus   MeSH
• myši MeSH
• neurozánětlivé nemoci MeSH
• Parkinsonova nemoc * patologie   MeSH
• rotenon toxicita   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Clinical diagnosis of Parkinson's disease (PD) occurs typically when a substantial proportion of dopaminergic neurons in the substantia nigra (SN) already died, and the first motor symptoms appear. Therefore, tools enabling the early diagnosis of PD are essential to identify early-stage PD patients in which neuroprotective treatments could have a significant impact. Here, we test the utility and sensitivity of the diffusion kurtosis imaging (DKI) in detecting progressive microstructural changes in several brain regions of mice exposed to chronic intragastric administration of rotenone, a mouse model that mimics the spatiotemporal progression of PD-like pathology from the ENS to the SN as described by Braak's staging. Our results show that DKI, especially kurtosis, can detect the progression of pathology-associated changes throughout the CNS. Increases in mean kurtosis were first observed in the dorsal motor nucleus of the vagus (DMV) after 2 months of exposure to rotenone and before the loss of dopaminergic neurons in the SN occurred. Remarkably, we also show that limited exposure to rotenone for 2 months is enough to trigger the progression of the disease in the absence of the environmental toxin, thus suggesting that once the first pathological changes in one region appear, they can self-perpetuate and progress within the CNS. Overall, our results show that DKI can be a useful radiological marker for the early detection and monitoring of PD pathology progression in patients with the potential to improve the clinical diagnosis and the development of neuroprotective treatments.

• MeSH
• aplikace orální MeSH
• bludiště - učení účinky léků   fyziologie   MeSH
• časové faktory MeSH
• dopaminergní neurony účinky léků   patologie   MeSH
• insekticidy toxicita   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• parkinsonské poruchy chemicky indukované   diagnostické zobrazování   patologie   MeSH
• progrese nemoci * MeSH
• rotenon aplikace a dávkování   toxicita   MeSH
• zobrazování difuzních tenzorů metody   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Numerous pathological changes of subcellular structures are characteristic hallmarks of neurodegeneration. The main research has focused to mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomal networks as well as microtubular system of the cell. The sequence of specific organelle damage during pathogenesis has not been answered yet. Exposition to rotenone is used for simulation of neurodegenerative changes in SH-SY5Y cells, which are widely used for in vitro modelling of Parkinson ́s disease pathogenesis. Intracellular effects were investigated in time points from 0 to 24 h by confocal microscopy and biochemical analyses. Analysis of fluorescent images identified the sensitivity of organelles towards rotenone in this order: microtubular cytoskeleton, mitochondrial network, endoplasmic reticulum, Golgi apparatus and lysosomal network. All observed morphological changes of intracellular compartments were identified before alphaS protein accumulation. Therefore, their potential as an early diagnostic marker is of interest. Understanding of subcellular sensitivity in initial stages of neurodegeneration is crucial for designing new approaches and a management of neurodegenerative disorders.

• MeSH
• apoptóza MeSH
• insekticidy toxicita   MeSH
• lidé MeSH
• mikrotubuly účinky léků   metabolismus   patologie   MeSH
• mitochondrie účinky léků   metabolismus   patologie   MeSH
• nádorové buněčné linie MeSH
• NADPH-oxidasy metabolismus   MeSH
• neuroblastom komplikace   MeSH
• neurodegenerativní nemoci etiologie   metabolismus   patologie   MeSH
• rotenon toxicita   MeSH
• viabilita buněk MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Reactive oxygen species (ROS) originating from mitochondria are perceived as a factor contributing to cell aging and means have been sought to attenuate ROS formation with the aim of extending the cell lifespan. Silybin and dehydrosilybin, two polyphenolic compounds, display a plethora of biological effects generally ascribed to their known antioxidant capacity. When investigating the cytoprotective effects of these two compounds in the primary cell cultures of neonatal rat cardiomyocytes, we noted the ability of dehydrosilybin to de-energize the cells by monitoring JC-1 fluorescence. Experiments evaluating oxygen consumption and membrane potential revealed that dehydrosilybin uncouples the respiration of isolated rat heart mitochondria albeit with a much lower potency than synthetic uncouplers. Furthermore, dehydrosilybin revealed a very high potency in suppressing ROS formation in isolated rat heart mitochondria with IC(50) = 0.15 μM. It is far more effective than its effect in a purely chemical system generating superoxide or in cells capable of oxidative burst, where the IC(50) for dehydrosilybin exceeds 50 μM. Dehydrosilybin also attenuated ROS formation caused by rotenone in the primary cultures of neonatal rat cardiomyocytes. We infer that the apparent uncoupler-like activity of dehydrosilybin is the basis of its ROS modulation effect in neonatal rat cardiomyocytes and leads us to propose a hypothesis on natural ischemia preconditioning by dietary polyphenols.

• MeSH
• analýza rozptylu MeSH
• benzimidazoly MeSH
• fluorescenční barviva MeSH
• inhibiční koncentrace 50 MeSH
• karbocyaniny MeSH
• kardiomyocyty metabolismus   MeSH
• krysa rodu rattus MeSH
• mitochondrie metabolismus   MeSH
• molekulární struktura MeSH
• potkani Wistar MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• rotenon toxicita   MeSH
• silymarin chemie   farmakologie   MeSH
• spotřeba kyslíku účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Vulnerability of mitochondrial Complex I to oxidative stress determines an organism's lifespan, pace of aging, susceptibility to numerous diseases originating from oxidative stress and certain mitopathies. The mechanisms involved, however, are largely unknown. We used confocal microscopy and fluorescent probe MitoSOX to monitor superoxide production due to retarded forward electron transport in HEPG2 cell mitochondrial Complex I in situ. Matrix-released superoxide production, the un-dismuted surplus (J(m)) was low in glucose-cultivated cells, where an uncoupler (FCCP) reduced it to half. Rotenone caused a 5-fold J(m) increase (AC(50) 2 microM), which was attenuated by uncoupling, membrane potential (DeltaPsi(m)), and DeltapH-collapse, since addition of FCCP (IC(50) 55 nM), valinomycin, and nigericin prevented this increase. J(m) doubled after cultivation with galactose/glutamine (i.e. at obligatory oxidative phosphorylation). A hydrophobic amiloride that acts on the ND5 subunit and inhibits Complex I H(+) pumping enhanced J(m) and even countered the FCCP effect (AC(50) 0.3 microM). Consequently, we have revealed a new principle predicting that Complex I produces maximum superoxide only when both electron transport and H(+) pumping are retarded. H(+) pumping may be attenuated by high protonmotive force or inhibited by oxidative stress-related mutations of ND5 (ND2, ND4) subunit. We predict that in a vicious cycle, when oxidative stress leads to higher fraction of, e.g. mutated ND5 subunits, it will be accelerated more and more. Thus, inhibition of Complex I H(+) pumping, which leads to oxidative stress, appears to be a missing link in the theory of mitochondrial aging and in the etiology of diseases related to oxidative stress.

• MeSH
• financování organizované MeSH
• fluorescenční barviva metabolismus   MeSH
• fosforylace účinky léků   MeSH
• glukosa chemie   MeSH
• intracelulární prostor metabolismus   účinky léků   MeSH
• konfokální mikroskopie MeSH
• lidé MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• mitochondriální DNA genetika   MeSH
• mitochondrie metabolismus   účinky léků   MeSH
• mutace MeSH
• nádorové buněčné linie MeSH
• nemoc MeSH
• oxidační stres účinky léků   MeSH
• respirační komplex I antagonisté a inhibitory   genetika   metabolismus   MeSH
• rotenon toxicita   MeSH
• rozpřahující látky toxicita   MeSH
• stárnutí MeSH
• superoxidy metabolismus   MeSH
• transport elektronů MeSH
• Check Tag
• lidé MeSH