Danos oxidativos e neurodegeneração: o quê aprendemos com animais transgênicos e nocautes?

Barbosa, Lívea Fujita; Medeiros, Marisa Helena Gennari de; Augusto, Ohára

doi:10.1590/s0100-40422006000600034

Cited by 14 publications

(12 citation statements)

References 59 publications

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“…The cellular degeneration promoted by oxidative stress occurs because of the cytotoxic effects of ROS, which include superoxide anion (O 2 ), hydroxyl radical (OH) and hydrogen peroxide (H 2 O 2 ) (Gutteridge, 1994;Barbosa et al, 2006;Halliwell and Gutteridge, 2015).…”

Section: Discussionmentioning

confidence: 99%

Can the exposure of Apis mellifera (Hymenoptera, Apiadae) larvae to a field concentration of thiamethoxam affect newly emerged bees?

et al. 2017

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The use of insecticides on crops can affect non-target insects, such as bees. In addition to the adult bees, larvae can be exposed to the insecticide through contaminated floral resources. Therefore, this study aimed to investigate the possible effects of the exposure of A. mellifera larvae to a field concentration of thiamethoxam (0.001 ng/μL thiamethoxam) on larval and pupal survival and on the percentage of adult emergence. Additionally, its cytotoxic effects on the digestive cells of midgut, Malpighian tubules cells and Kenyon cells of the brain of newly emerged A. mellifera bees were analyzed. The results showed that larval exposure to this concentration of thiamethoxam did not influence larval and pupal survival or the percentage of adult bee emergence. However, this exposure caused ultra-structural alterations in the target and non-target organs of newly emerged bees. The digestive cell of bees that were exposed to the insecticide exhibited a basal labyrinth without long and thin channels and compromised mitochondria. In Malpighian tubules cells, disorganized basal labyrinth, dilated mitochondria with a deformed shape and a loss of cristae, and disorganized microvilli were observed. The results showed that the exposed bees presented Kenyon cells with alterations in the nucleus and mitochondria. These alterations indicate possible tissue degeneration, demonstrating the cytotoxicity of thiamethoxam in the target and non-target organs of newly emerged bees. Such results suggest cellular organelle impairment that can compromise cellular function of the midgut cells, Malpighian tubules cells and Kenyon cells, and, consequently, can compromise the longevity of the bees of the whole colony.

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Section: Discussionmentioning

confidence: 99%

Can the exposure of Apis mellifera (Hymenoptera, Apiadae) larvae to a field concentration of thiamethoxam affect newly emerged bees?

et al. 2017

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“…Catalase is an additional enzymatic defense against ROS. In nervous tissues there are typically low levels of catalase, and its evaluation is important due to oxidative metabolism and intense free radicals' generation, showing a more specific protection against H 2 O 2 produced under pathological conditions (Shim et al 2003, Barbosa et al 2006. Catalase activity showed dose dependent results in both hippocampus and striatum areas, indicating that doses higher than 25 mg/kg could overcome AA in the modulation of the enzyme.…”

Section: Discussionmentioning

confidence: 99%

Counteracting effects on free radicals and histological alterations induced by a fraction with casearins

Araújo

Oliveira

Sousa

et al. 2015

An. Acad. Bras. Ciênc.

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Casearia sylvestris Swartz is a medicinal plant widely distributed in Brazil. It has anti-inflammatory, antiulcer and antitumor activities and is popularly used to treat snakebites, wounds, diarrhea, flu and chest colds. Its leaves are rich in oxygenated tricyclic cis-clerodane diterpenes, particulary casearins. Herein, we evaluated the antioxidant activities of a fraction with casearins (FC) isolated from C. sylvestris and histological changes on the central nervous system and livers of Mus musculus mice. Firstly, in vitro studies (0.9, 1.8, 3.6, 5.4 and 7.2 μg/mL) revealed EC50 values of 3.7, 6.4 and 0.16 µg/mL for nitrite, hydroxyl radical and TBARS levels, respectively. Secondly, FC (2.5, 5, 10 and 25 mg/kg/day) was intraperitoneally administered to Swiss mice for 7 consecutive days. Nitrite levels in the hippocampus (26.2, 27.3, 30.2 and 26.6 µM) and striatum (26.3, 25.4, 34.3 and 27.5 µM) increased in all treated animals (P < 0.05). Lower doses dropped reduced glutathione, catalase and TBARS levels in the hippocampus and striatum. With the exception of this reduction in TBARS formation, FC displayed only in vitro antioxidant activity. Animals exhibited histological alterations suggestive of neurotoxicity and hepatotoxicity, indicating the need for precaution regarding the consumption of medicinal formulations based on Casearia sylvestris.

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“…Free radical species (FRs) are highly unstable and can react with cellular components. Under normal conditions, the production of these species is balanced by the presence of a sophisticated defense mechanism consisting of enzymatic and non-enzymatic components (Barbosa et al, 2006;Imai and Nakagawa, 2006) such as superoxide dismutases (SOD), catalases (CAT), glutathione peroxidases (GPx), and other components (Spadiene et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Ginkgo bilobaL.: Phytochemical components and antioxidant activity

Fermino¹,

Milanez²,

Freitas³

et al. 2015

Afr. J. Pharm. Pharmacol.

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Curative effects of Ginkgo biloba L. have been recognized for centuries, dating back to traditional Chinese medicine which used crushed leaves to treat several health problems. Although G. biloba L. has several known and investigated activities, the antioxidant activity of its extract (EGb 761) is particularly relevant because reactive oxygen (ROS) and reactive nitrogen (RNS) species are constantly produced in aerobic organisms. Currently, the exploitation of the antioxidant activity of G. biloba extract Egb 761 has been of particular pharmacological importance because oxidative stress may be harmful to cells and may trigger the development of many disorders. The antioxidant activity of the EGb extract against oxidative stress has been associated with several therapeutic effects and currently, Egb761 is indicated to treat labyrinthitis, headache, memory disturbance, intermittent claudication, dementia, Alzheimer's disease, glaucoma, cardiovascular disorders, cerebral ischemia, increased libido and sexual activity, and psychiatric diseases, such as depression. This study is a review of basic and clinical studies related to antioxidant properties of G. biloba L.

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Danos oxidativos e neurodegeneração: o quê aprendemos com animais transgênicos e nocautes?

Cited by 14 publications

References 59 publications

Can the exposure of Apis mellifera (Hymenoptera, Apiadae) larvae to a field concentration of thiamethoxam affect newly emerged bees?

Can the exposure of Apis mellifera (Hymenoptera, Apiadae) larvae to a field concentration of thiamethoxam affect newly emerged bees?

Counteracting effects on free radicals and histological alterations induced by a fraction with casearins

Ginkgo bilobaL.: Phytochemical components and antioxidant activity

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