Oxidative stress: Clinical diagnostic significance

Elevated free radical production and/or insufficient antioxidative defense results in cellular oxidant stress responses. Sustained and/or intense oxidative insults can overcome cell defenses resulting in accumulated damage to macromolecules, leading to loss of cell function, membrane damage, and ultimately to cell death. Oxidative stress (OS) can result from conditions including excessive physical stress, exposure to environmental pollution and xenobiotics, and smoking. Oxidative stress, as a pathophysiological mechanism, has been linked to numerous pathologies, poisonings, and the ageing process. Reactive oxygen species and reactive nitrogen species, endogenously or exogenously produced, can readily attack all classes of macromolecules (proteins, DNA, unsaturated fatty acid). The disrupted oxidative-reductive milieu proceeds via lipid peroxidation, altered antioxidative enzyme activities and depletion of non-enzymatic endogenous antioxidants, several of which can de detected in the pre-symptomatic phase of many diseases. Therefore, they could represent markers of altered metabolic and physiological homeostasis. Accordingly, from the point of view of routine clinical-diagnostic practice, it would be valuable to routinely analyze OS status parameters to earlier recognize potential disease states and provide the basis for preventative advance treatment with appropriate medicines.Povećano stvaranje slobodnih radikala i/ili nedovoljna antioksidativna zaštita dovodi do oksidativnog stre sa (OS) u ćeliji. Produženi i/ili snažan oksidativni insult prevazilazi ćelijski antioksidativni odbrambreni kapacitet, dolazi do oštećenja makromolekula, gubi se ćelijska funkcija, oštećuju se membrane, što sve zajedno dovodi do smrti ćelije. Stanja organizma kao što su povećana fizička aktivnost, izloženost zagađenju čovekove okoline, ksenobioticima, pušenje itd. rezultiraju OS. Oksidativni stres, kao patofiziološki mehanizam, je potvrđen u brojnim patologijama, trovanjima i starenju. Reaktivne kiseonične vrste i reaktivne azotove vrste, endogenog ili egzogenog porekla, mogu lako da napadnu sve klase biomolekula (proteni, DNK, nezasićene masne kiseline). Narušen oksido-reduktivni milje, koji posreduje povećanju lipidne peroksidacije, promeni aktivnosti direktnih ili indirektnih antioksidativnih enzima, kao i smanjenom sadržaju neenzimskih antioksidanasa, može biti prepoznat u presimptomatskoj fazi brojnih bolesti. U tom smislu može biti pokazatelj izmenjenih metaboličkih i funkcionalnih zbivanja. U svakodnevnoj kliničko-dijagnostičkoj praksi analize parametara OS u biološkom materijalu bi trebalo da imaju svoje mesto, radi rane dijagnoze bolesti, prevencije i unapređivanja terapije.

Effects of nerve and fibroblast growth factors on the production of nitric oxide in experimental model of Huntington's disease

The role of nitric oxide (NO) in neurological diseases represents one of the most studied, yet controversial subjects in physiology. The aim was to examine the effects of intrastriatal injection neurotrophins (nerve growth factors-NGF, fibroblast growth factors-FGF) in order to investigate the possible involvement of NO in quinolinic acid (QA) induced striatum toxicity in the rat model of Huntington's disease (HD). QA was administered unilaterally into the striatum of adult Wistar rats in a single dose of 150 nM. The other two groups of animals were pretreated immediately before QA application with NGF and FGF, respectively. Control group was treated with 0.9% saline solution in the same manner. Animals were decapitated 7 days after the treatment. Nitrite levels were significantly decreased both in the ipsi- and contra lateral striatum and forebrain cortex of NGF- and FGF-treated animals compared with QA treatment. These results indicated a temporal and spatial propagation of oxidative stress and spread protective effects of NGF and FGF on the forebrain cortex, the distant structure, but tightly connected with striatum, the place of direct neurotoxin damage. Neurotrophins could be the potential neuroprotective agents in HD

Total anesthesia, rats brain surgery, nitric oxide (NO) and free radicals

It is expected that clinical recovery after surgically induced brain trauma is followed by molecular and biochemical restitution. Seven days after surgery, we investigated whether the plastic cannula implanted in the left brain ventricle of adult Wistar rats (n = 6-7), performed in pentobarbital anesthesia, could influence oxidative stress elements (superoxide anion and lipid peroxidation), as well as the antioxidative system (superoxide dismuthase-SOD). Also, we investigated whether nitric oxide (NO) is involved in these processes. Biochemical analyses was performed in the forebrain cortex, striatum and hippocampus. Clinical recovery was complete seven days after surgery. Thereafter, thirty minutes before decapitation, through the cannula, one group of rats received saline intracerebroventricularly (control group), and the treated group received Nω-nitro-L-arginine methyl ester (L-NAME). The third group was left unoperated and untreated. Before and after the treatments, rectal body temperature was measured. Compared to the untreated group the index of lipid peroxidation was increased in all three brain structures in the group that received saline (p<0.05 to 0.01). Application of L-NAME deteriorated it in the striatum and hippocampus (p<0.01 compared to the both other groups), but the value in the forebrain cortex was similar to the untreated group. Supeoxide anion level was decreased in the L-NAME treated group only in the striatum (p<0.01 compared to control and untreated groups), but SOD was increased in the hippocampus compared to the saline treated group (p<0.05). Seven days after brain surgery in pentobarbital anesthesia, recovery of biochemical disturbances was not parallel to clinical recovery. Long lasting biochemical changes are rather the consequence of brain injury than to pentobarbital anesthesia. In this experimental model, NO had protective effects, acting against lipid per oxidation in the striatum and hippocampus, but not in the forebrain cortex i. e. NO involvement in the free radical processes strongly depends on the observed brain region.Posle hirurške intervencije na mozgu, očekuje se paralelizam između kliničkog, sa jedne strane, i molekulskog i biohemijskog oporavka, sa druge strane. Da bi to utvrdili, u tri moždane strukture (kora prednjeg mozga strijatum, hipokampus) odraslih Vistar pacova muškog pola, ispitivali smo promene pojedinih prooksidativnih i antioksdativnih parametara, nastalih posle usađivanja plastične kanile u bočnu komoru mozga, kroz koju su ubrizgavane ispitivane supstance (10pi). Kao opšti anestetik korišćen je pentobarbiton natrijum (0,045 g/kg). Eksperiment je nastavljen sedam dana posle operacije, kada su pacovi bili klinički potpuno oporavljeni. Pre ubrizgavanja 0,9% NaCI jednoj grupi (kontrola) i Nω-nitro-L-arginin metil estra (L-NAME, 10 mikrograma, rastvoren u 0,9% NaCI) drugoj grupi, kao i 30 minuta posle toga, merena je rektalna temperatura kod sve tri grupe pacova (treću su činili intaktni pacovi, 6-7 pacova u svakoj grupi). Porast indeksa lipidne peroksidacije u sve tri moždane strukture operisanih pacova koji su dobili NaCI bio je statistički značajan u odnosu na intaktnu grupu. Ubrizgavanjem L-NAME, ove promene su u strijatumu i hipokampusu postale statistički još izraženije u odnosu na grupu koja je dobila NaCI, dok je u kori prednjeg mozga registrovan sasvim slab porast u odnosu na intaktnu grupu. Istovremeno, ometanje sinteze NO bilo je praćeno statistički značajnim padom superoksidnog radikala u strijatumu u odnosu na obe grupe, i porastom superoksid dizmutaze u hipokampusu u odnosu na grupu koja je dobila NaCI. Telesna temperature je bila normalna kod svih pacova u oba vremena merenja. Dokazano je da ne postoji paralelizam između kliničkog i biohemijskog oporavka posle operacije na mozgu pacova, izvedene u opštoj anesteziji uz primenu pentobarbitona. To je ispoljeno pojačanom lipidnom peroksidacijom sedam dana posle operacije u sve tri ispitivane strukture mozga koji su dobili NaCI. Porast lipidne peroksidacije je najverovatnije posledica mehaničkog oštećenja izazvanog operacijom, pre nego same anestezije. U ovim procesima, NO ima značajnu regulatornu ulogu, pri čemu njegovi efekti nisu podjednako ispoljeni u svim delovima mozga. Njegova snažna antioksidativna svojstva registruju se u hipokampusu i strijatumu ali ne i u kori prednjeg mozga, što govori u prilog selektivne osetljivosti mozga.nul

Effects of various nitric oxide synthase inhibitors on AlCl3-induced neuronal injury in rats

The present study was aimed at determining the effectiveness of nitric oxide synthase (NOS) inhibitors: N-nitro-L-arginine methyl ester, 7-nitroindazole and aminoguanidine in modulating the toxicity of AlCl3 on superoxide production and the malondialdehyde concentration of Wistar rats. The animals were sacrificed 10 min and 3 days after the treatment and the forebrain cortex was removed. The results show that AlCl3 exposure promotes oxidative stress in different neural areas. The biochemical changes observed in the neuronal tissues show that aluminum acts as pro-oxidant, while NOS inhibitors exert an anti-oxidant action in AlCl3-treated animals.U eksperimentu je određivana efikasnost inhibitora azot-oksid-sintaze (NOS): metil-estra N-nitro-L-arginina, 7-nitroindazola i aminogvanidina u modulaciji toksičnosti AlCl3 na stvaranje superoksidnog anjona i koncentraciju malondialdehida kod Wistar pacova. Životinje su žrtvovane 10 min i 3 dana nakon tretmana i izolovana je kora velikog mozga. Rezultati pokazuju da izlaganje AlCl3 pokreće oksidativni stres u različitim moždanim regionima. Biohemijske promene opisane u neuronskom tkivu pokazuju da aluminijum deluje kao pro-oksidant, dok inhibitori NOS imaju antioksidativno dejstvo kod životinja tretiranih AlCl3.nul

Nitric oxide (NO) and an NMDA receptor antagonist in pentylenetetrazole-induced convulsions

Controversy about proconvulsant and anticonvulsant nitric oxide (NO) effects and the place of oxidative stress in convulsions, are still a matter of research. We investigated the interaction between 2-amino-5-phosphonovaleric acid (APV), a competitive N-methyl-D-aspartate (NMDA) receptor antagonist and Nw-nitro-L-arginine methyl ester (L-NAME), a nonselective nitric oxide synthase (NOS) antagonist, in pentylenetetrazole (PTZ)-induced convulsions. Pentylenetetrazole was applied to adult Wistar rats intraperitoneally (ip) in a single dose of 80 mg/kg, and L-NAME (10 µg/10 µl) or APV (20 µg/10 µl) intracerebroventricularly (icv), 30 and 10 minutes before PTZ, respectively. In the same manner, another group received both antagonists. Control animals were given 0.9% saline. Nw-nitro-L-arginine methyl ester exerted a weak anticonvulsant effect, preventing generalized clonic (GCC) and clonic-tonic convulsions (CTC) in 17% of cases. With APV protection against GCC and CTC was 100%, forelimb dystonia (FLD) was decreased in 33% of cases, and time to onset of all convulsive patterns was prolonged (p<0.05 to 0.01). All effects of APV, except in CTC, were reversed by L-NAME applied prior to APV. In APV-PTZ treated animals, superoxide anion content was increased in the forebrain cortex, striatum and hippocampus, without an overwhelmed antioxidative superoxide dismutase (SOD) defense system in the other treatments. When the APV-PTZ group was treated with L-NAME, both SOD activity and superoxide anion content were additionally decreased indicating that the NOS-NO system was involved in the metabolism of superoxide anions. It is suggested that clinical and biochemical effects of NO strongly depend upon the pretreatment and might lead to a wrong impression of NO contradictory activity.Kontroverzni nalazi o prokonvulzivnim kao i antikonvulzivnim efektima azot oksida (NO) i značaju oksidativnog stresa u konvulzijama, i dalje su predmet istraživanja. U konvulzijama izazvanim primenom pentilentetrazola (PTZ) ispitivali smo interakciju između 2-amino-5-fosfovalerinske kiseline (APV) kompetitivnog antagoniste N-metil-D-aspartat (NMDA) receptora i Nw-nitro-L-arginin metil estra (L-NAME), neselektivnog antagoniste azot oksid sintaze (NOS). Odraslim pacovima Wistar soja, PTZ je ubrizgavan intraperitonealno (ip) u jednoj dozi od 80 mg/kg. Ostale supstance, L-NAME (10 µg/10 µl) i APV (20 µg/10 µl), primenjivale su se intracerebroventrikularno (icv), i to L-NAME 30, a APV 10 minuta pre PTZ. Po istom vremenskom principu, jedna grupa dobila je oba antagonista, a kontrolna fiziološki rastvor NaCl. Nw-nitro-L-arginin metil estar ispoljio je slabo antikonvulzivno dejstvo, smanjujući incidenciju generalizovanih kloničnih (GCC) i klonično-toničnih konvulzija (CTC) za 17%. Za razliku od L-NAME, APV je sprečila nastanak GCC i CTC kod svih životinja (100%), a incidencija klonusa prednjih nogu (FLD) smanjena je za 33%. Istovremeno primenom APV produženo je vreme od aplikacije PTZ do pojave svih konvulzivnih tipova (p<.05 do 0.01). Primenom L-NAME pre APV, umanjeni su efekti APV, pri čemu je došlo do povećanja incidencije FLD i GCC za 16% odnosno 50%. U kori prednjeg mozga, strijatumu i hipokampusu, životinja koje su dobile APV+PTZ, došlo do povećanja koncentracije superoksidnog anjona. Aktivnost superoksid dizmutaze ne prati ovaj skok. Njen dodatni pad u grupi tretiranoj sa L-NAME pre APV+PTZ, ukazuje da je sistem NOS-NO uključen u metabolizam superoksidnog anjona. Dobijeni rezultati ukazuju da klinički i biohemijski efekti NO u velikoj meri zavise od prethodno primenjenih supstanci i promena izazvanih njima, što može da doprinose sticanju pogrešnog utiska o kontradiktornim dejstvima NO.nul

Umerena radioprotektivna uloga zeolita kod pacova

Background/Aim. Exposure of living organisms to γ- radiation results in the overproduction of free radicals. The aim of the study was to test if the subacute administration of micronized zeolite (MZC) accomplishes radioprotective role based on the evaluation of the status of oxidative stress (OS) in the brain and 8-hydroxyguanosine (8-OH-dG) in the plasma of the rats exposed to the single γ-ray irradiation of 2 and/or 10 Gray (Gy). Methods. Wistar rats were on a four-week normal or 5% MZC supplemented diet and af- terward exposed to the single γ-ray irradiation of 2 and 10 Gy. Groups of rats were: a) on a normal diet (the control group, and 2Gy and 10Gy groups); b) on 5% MZC supple- mented diet (the control group – MZC, MZC + 2Gy, and MZC + 10Gy groups). We measured malondialdehyde (MDA), glutathione (GSH) total, and activity of total super- oxide dismutase (tSOD) and manganese superoxide dis- mutase (MnSOD) in vulnerable brain regions (cerebellum, hippocampus, and cerebral cortex) and 8-OH-dG in plasma. Results. Lower MDA was found in the MZC+2Gy and MZC+10Gy groups compared to the 2Gy and 10Gy groups. Activity od total SOD was higher in the MZC+10Gy group than in the 10Gy one. GSH was the highest in the 10Gy group. Compared to the control group, 8-OH-dG was extremely higher in groups radiated with 10 Gy regardless of a diet, but slightly lower in the MZC+2Gy and 2Gy groups. Conclusion. Subacute MZC pretreatment accomplished partial radioprotective effect in irradiated rats compared to non-irradiated rats, based on suppressed SOD activity at 2 Gy, and reduced brain MDA when exposed to 2 Gy and 10 Gy.Uvod/Cilj. Izlaganje živih organizama gama zračenju re- zultira hiperprodukcijom slobodnih radikala. Cilj istraživanja je bio da se ispita da li subakutna ishrana dopunjena sa 5% mikronizovanog zeolita (MZC) ispoljava radiozaštitnu ulogu na osnovu statusa oksidativnog stresa (OS) u mozgu i 8- hidroksiguanozina (8-OH-dG) u plazmi pacova izloženih pojedinačnim dozama jonizujućeg zračenja od 2 i 10 Gray (Gy). Metode. Wistar pacovi su bili na četvoronedeljnoj normalnoj ishrani ili ishrani obogaćenoj sa 5% MZC, posle čega su bili izloženi pojedinačnom jonizujućem zračenju od 2 Gy, odnosno 10 Gy. Grupe pacova bile su: a) gru pa pacova na normalnoj ishrani (kontrolna grupa i grupe 2Gy i 10Gy); b) grupa pacova na ishrani obogaćenoj sa 5% MZC (kontrolna grupa – MZC i grupe MZC+2Gy i MZC+10Gy). Meren je malondialdehid (MDA), glutation (GSH) i aktivnost ukupne (tSOD) i mangan superoksid dizmutaze (MnSOD) u osetljivim strukturama mozga (cerebelum, hipokampus i cerebralni korteks), a 8-OH-dG u plazmi. Rezultati. Biomarker MDA je bio niži u MZC+2Gy i MZC+10Gy grupama, u odnosu na grupe 2Gy i 10Gy. Aktivnost ukupne SOD je bila viša u grupi MZC+10Gy, u odnosu na grupu 10Gy. Najviši nivo GSH bio je u grupi 10Gy. U pređenju sa kontrolnom grupom, 8- OH-dG je bio izuzetno viši u grupama ozračenim sa 10 Gy, bez obzira na dijetetski režim i niži u grupama MZC+2Gy i 2Gy. Zaključak. Pacovi koji su bili na režimu ishrane obogaćene sa 5% MZC bili su delimično zaštićeni od zračenja, shodno redukovanoj moždanoj aktivnosti SOD pri 2 Gy i sniženom nivou MDA pri izlaganju zračenju od 2 i 10 Gy

Disulfiram partially improves oxidative but not androgen status in rats exposed to cadmium

We investigated the effect of disulfiram (DSF) on reproductive toxicity induced by subchronic exposure to cadmium (Cd). We examined the redox status and systemic testosterone changes in the testes and plasma of Cd-treated male Wistar rats. Rats were treated with 1 mg CdCl2/kg body weight (bw)/day (intraperitoneal administration) for 42 days; in the second experimental group, rats were given 178.5 mg DSF/kg bw/day by oral gavage for 21 days; in the third group, after administration of Cd for 21 days, DSF treatment was introduced on day 22 and lasted until day 42, with continuous Cd intake. Each experimental group had a matching control: untreated rats, rats that received for 21 days olive oil, the solvent for DSF; rats that started with olive oil intake from days 22-42. Exposure of rats to DSF modulated the oxidative status in the testes; thus, coexposure increased the Cd-induced reduction in total superoxide dismutase (tSOD), catalase ( CAT), glutathione reductase (GR) and total glutathione-S-transferase (tGST) activities, and lowered the Cd-increased superoxide anion radical (O-2(center dot-)) and malondialdehyde (MDA) concentrations. DSF did not affect testosterone production diminished by Cd, as Leydig cells, once impaired by Cd, could not be reactivated by DSF

Compensatory Neuroprotective Response of Thioredoxin Reductase against Oxidative-Nitrosative Stress Induced by Experimental Autoimmune Encephalomyelitis in Rats: Modulation by Theta Burst Stimulation

Cortical theta burst stimulation (TBS) structured as intermittent (iTBS) and continuous (cTBS)could prevent the progression of the experimental autoimmune encephalomyelitis (EAE). The interplayof brain antioxidant defense systems against free radicals (FRs) overproduction induced by EAE,as well as during iTBS or cTBS, have not been entirely investigated. This study aimed to examinewhether oxidative-nitrogen stress (ONS) is one of the underlying pathophysiological mechanisms ofEAE, which may be changed in terms of health improvement by iTBS or cTBS. Dark Agouti strainfemale rats were tested for the effects of EAE and TBS. The rats were randomly divided into the controlgroup, rats specifically immunized for EAE and nonspecifically immuno-stimulated with CompleteFreund’s adjuvant. TBS or sham TBS was applied to EAE rats from 14th–24th post-immunizationday. Superoxide dismutase activity, levels of superoxide anion (O2•–), lipid peroxidation, glutathione(GSH), nicotinamide adenine dinucleotide phosphate (NADPH), and thioredoxin reductase (TrxR)activity were analyzed in rat spinal cords homogenates. The severity of EAE clinical coincided withthe climax of ONS. The most critical result refers to TrxR, which immensely responded against theapplied stressors of the central nervous system (CNS), including immunization and TBS. We foundthat the compensatory neuroprotective role of TrxR upregulation is a positive feedback mechanismthat reduces the harmfulness of ONS. iTBS and cTBS both modulate the biochemical environmentagainst ONS at a distance from the area of stimulation, alleviating symptoms of EAE. The results ofour study increase the understanding of FRs’ interplay and the role of Trx/TrxR in ONS-associatedneuroinflammatory diseases, such as EAE. Also, our results might help the development of new ideasfor designing more effective medical treatment, combining neuropsychological with noninvasiveneurostimulation–neuromodulation techniques to patients living with MS

Efekat predtretmana sa l-name na glutation i glutation peroksidazu u strijatumu pacova na neurotoksičnost izazvanu parakvatom

Contact herbicide paraquat (DQ) is bipyridylium compound, which undergoes redox metabolism; hence enlarged in humans radical production mediated its toxicity. Target organs of systemic effect of PQ poisoning are lung and kidney. The mechanism of PQ-induced neurotoxicity is not elucidated till now. The objective of our study was to examine the role of nitric oxide (NOx) in PQ-induced neurotoxicity, primarily focusing on glutathione cycles [total glutathione content (GSH) and glutathione peroxidase (GPx) activity]. In order to investigate the role of NOx in oxidative stress (OS) and/or nitrosative stress (NS) response to PQ neurotoxicity, we used NG-nitro-L-arginine methyl ester (L-NAME), a non-selective inhibitor of nitric oxide synthase (NOS) in the pretreatment of PQ administration. Study was conducted on Wistar rats randomly divided in groups (n=8 for controls and n=24 for experimental groups) depending on the applied treatments. The tested compounds were intrastriatally (i.s.) administered. Measuring of GSH content and GPx activity was performed at 30 min, 24 hours and 7 days after treatments. Parkinsonism’s like symptoms were observed only in the group of rats treated with PQ. The L-NAME protected animals from PQ-induced neurotoxicity, which could be concluded from the absence of Parkinsonism’s like symptoms and reduced OS/NS response in the striatum of rats pretreated with L-NAME.Kontaktni herbicid parakvat (PK) je dipiridinsko jedinjenje, koje podleže redoks metabolizmu i svoju toksičnost ispoljava posredstvom povećanog stvaranja slobodnih radikala. Ciljni organi sistemskog toksičnog efekta PK kod čoveka su pluća i bubrezi. Mehanizam PKindukovane neurotoksičnosti do sada još uvek nije u potpunosti rasvetljen. Cilj našeg rada bio je da se ispita uloga azot oksida (NOx) u neurotoksičnosti PK, sa posebnim osvrtom na glutationski ciklus [glutation (GSH) i enzim glutation peroksidazu (GPx)]. U cilju da se istraži uloga NOx u oksidativnom stresu (OS) i / ili nitrosativnom stresu (NS), kao odgovoru na neurotoksičnost PK. U predtretmanu parakvatom koristili smo NG-nitro- L-arginin metil estar (L-NAME), neselektivni inhibitor azot oksid sintetaze (NOS), aplikovan je pre davanja PQ . Studija je sprovedena na pacovima Wistar soja nasumice podeljenim u grupe (n = 8 za kontrolnu grupu i n = 24 za eksperimentalne grupe) u zavisnosti od tretmana. Testirana jedinjenja su intrastrijatalno (i.s.) aplikovana. Merenje sadržaja GSH i aktivnosti GPx izvršena su 30 min, 24 sata i 7 dana posle tretmana. Parkinsonizam je kao simptom primećen samo u grupi pacova tretiranih PK - om. L-NAME je ispoljio zaštitni efekat kod životinja kod kojih je i.s. davan PK, što bi se moglo zaključiti na osnovu odsustva simptoma parkinsonizma i smanjenog OS/NS odgovora u strijatumu u grupi pretretiranoj sa L-NAME