Ozone protective effects against PTZ-induced generalized seizures are mediated by reestablishment of cellular redox balance and A1 adenosine receptors.

OBJECTIVES: Epilepsy is a common seizure disorder affecting approximately 70 million people worldwide. Mitochondrial dysfunction and antioxidant/prooxidant imbalance are emerging as factors that contribute to epileptogenesis. As medical ozone was able to reestablish cellular redox balance and to maintain the protective effects mediated by A1 receptors (A1Rs), the aim of this work was to study ozone's effects on antioxidant/prooxidant balance and to clarify if A1Rs play a role in ozone's protective actions against pentylenetetrazole (PTZ)-induced convulsions in mice. METHODS: Influence of ozone's treatments in mice submitted to PTZ-induced seizures was studied. Ozone was administered by rectal insufflation 1 mg/kg (5, 10, 15, 20 treatments), one per day, of 1-1·5 ml at an ozone concentration of 20 µg/ml. Mice received PTZ (90 mg/kg i.p.) 24 hours after the last ozone treatment. Oxygen control groups 26 mg/kg were introduced. Latency to first seizure was determined. Antioxidant/prooxidant balance in brain homogenates was studied. A1 adenosine receptors' effects on ozone's protective actions against seizures were evaluated using 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). RESULTS: Highest latency was observed when mice received 15 ozone treatments. Oxygen + PTZ group did not achieve protection against neither convulsions nor brain oxidative injury. Fifteen treatments of ozone protected against biomolecules oxidative damage and the antioxidant systems as well. 8-Cyclopentyl-1,3-dipropylxanthine abolished the ozone's protection. CONCLUSIONS: Ozone therapy increased the latency for the first seizure and the survival percentage. These effects are discussed in point of ozone's capacity to reestablish cellular redox balance, decrease biomolecules damage, and regulate activation of A1 adenosine receptors in PTZ-induced seizures.

Ozone oxidative postconditioning ameliorates joint damage and decreases pro-inflammatory cytokine levels and oxidative stress in PG/PS-induced arthritis in rats.

Rheumatoid Arthritis (RA) is the most prevalent chronic condition present in ~1% of the adult population. Many pro-inflammatory mediators are increased in RA, including Reactive Oxygen Species such as nitric oxide NO, pro-inflammatory cytokines as tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1ß) and other molecules. Ozone oxidative postconditioning has regulatory effects on some pathological targets associated with RA. Thus, the aim of this study was to investigate the efficacy of ozone therapy in PG/PS-induced arthritis in rats in point of joints inflammation and morphology. Moreover, cytokines, nitric oxide and oxidative stress levels in spleen homogenates were evaluated. Ozone treatment ameliorated joint damage, reduced TNF-α concentrations as well as TNF-α and IL-1ß mRNA levels. Besides, cellular redox balance, nitric oxide and fructolysine levels were reestablished after ozone oxidative postconditioning. It was concluded that pleiotropic ozone's effects clarify its therapeutic efficacy in RA. Decreasing inflammation and joint injury, reduction of pro-inflammatory cytokines, TNF-α and IL-1ß transcripts and re-establishment of cellular redox balance after ozone treatment were demonstrated.

Ischaemic and pharmacological preconditionings protect liver via adenosine and redox status following hepatic ischaemia/reperfusion in rats.

Although IPC (ischaemic preconditioning) is considered as a protective strategy in HI/R (hepatic ischaemia/reperfusion), the mechanisms for this effect have not been fully elucidated. In the present study we investigate whether PPC (pharmacological preconditioning) by transient activation of A(1)R (adenosine A(1) receptor) protects against long-term HI/R and whether the protective effects of IPC depend on A(1)R activation and whether both preconditionings affect remote organs. Wistar rats underwent IPC and long-term HI/R. Another set of animals were pharmacologically preconditioned with the A(1)R-agonist CCPA [2-chloro-N(6)-cyclopentyladenosine; 0.1 mg/kg of body weight, i.p. (intraperitoneally)] 24 h before HI/R. In other groups, rats received an A(1)R-antagonist, DPCPX (1,3-dipropyl-8-cyclopentylxanthine; 0.1 mg/kg of body weight, i.p.) 24 h before HI/R. Hepatic damage was evaluated by transaminase [AST (aspartate transaminase), ALT (alanine transaminase)] release; inflammation was assessed by hepatic MPO (myeloperoxidase) and serum TNFalpha (tumour necrosis factor alpha) and NO; oxidative stress was estimated by MDA (malondialdehyde) and 4-HDA (4-hydroxyalkenals), SOD (superoxide dismutase) activity, GSH and ADA (adenosine deaminase) as adenosine metabolism. Both preconditionings protected liver and lung against HI/R as indicated by the reduction in transaminases, MPO, MDA+4-HDA, NO, TNFalpha and ADA activity as compared with HI/R (P<0.05). However, pre-treatment with DPCPX abolished the protective effects of IPC and PPC. Preconditionings induced a significant increase in hepatic MnSOD (manganese SOD) activity and NO generation compared with the sham group, and this activity was abolished by DPCPX pre-treatment. A(1)R activation induced hepatic delayed preconditioning and blockade of A(1)R abolished hepatic IPC. IPC, as well as PPC, were able to prevent lung damage. These protective effects are associated with a reduction in oxidative stress, inflammation and endogenous antioxidant preservation.

Prion protein potentiates acetylcholine release at the neuromuscular junction.

Cellular prion protein (PrP(c)), the normal isoform of the pathogenic peptide (PrP(sc)) responsible of the transmissible spongiform encephalopaties (TSEs), is present in many neural tissues, including neuromuscular junctions (NMJ). To analyze if this protein could influence the synaptic transmission, we performed an electrophysiological approach to study the effect of cellular prion protein on a mammalian neuromuscular junction. The loose patch clamp (LPC) technique enables the study of the whole preparation including the pre- and the post-synaptic domains. In a mouse phrenic-diaphragm preparation, nanomolar concentrations of cellular prion protein were able to induce a very striking potentiation of the acetylcholine (ACh) release. The effect was mainly pre-synaptic with an increase of the amplitude of the miniature end-plate currents, probably calcium dependent. Moreover, an apparent facilitation of the synaptic transmission was noted. The results clearly indicate that cellular prion protein may play a key role in the function of the neuromuscular junction.

Effects of ozone oxidative preconditioning on nitric oxide generation and cellular redox balance in a rat model of hepatic ischaemia-reperfusion.

BACKGROUND: Many studies indicate that oxygen free-radical formation after reoxygenation of liver may initiate the cascade of hepatocellular injury. It has been demonstrated that controlled ozone administration may promote an oxidative preconditioning or adaptation to oxidative stress, preventing the damage induced by reactive oxygen species and protecting against liver ischaemia-reperfusion (I/R) injury. AIMS: In the present study, the effects of ozone oxidative preconditioning (OzoneOP) on nitric oxide (NO) generation and the cellular redox balance have been studied. METHODS: Six groups of rats were classified as follows: (1). sham-operated; (2). sham-operated+l-NAME (N(omega)-nitro-l-arginine methyl ester); (3). I/R (ischaemia 90 min-reperfusion 90 min); (4). OzoneOP+I/R; (5). OzoneOP+l-NAME+I/R; and (6). l-NAME+I/R. The following parameters were measured: plasma transaminases (aspartate aminotransferase, alanine aminotransferase) as an index of hepatocellular injury; in homogenates of hepatic tissue: nitrate/nitrite as an index of NO production; superoxide dismutase (SOD), catalase (CAT) and glutathione levels as markers of endogenous antioxidant system; and finally malondialdehyde+4-hydroxyalkenals (MDA+4-HDA) and total hydroperoxides (TH) as indicators of oxidative stress. RESULTS: A correspondence between liver damage and the increase of NO, CAT, TH, glutathione and MDA+4-HDA concentrations were observed just as a decrease of SOD activity. OzoneOP prevented and attenuated hepatic damage in I/R and OzoneOP+l-NAME+I/R, respectively, in close relation with the above-mentioned parameters. CONCLUSIONS: These results show that OzoneOP protected against liver I/R injury through mechanisms that promote a regulation of endogenous NO concentrations and maintenance of cellular redox balance. Ozone treatment may have important clinical implications, particularly in view of the increasing hepatic transplantation programs.