Cinzia Nasuti

Cypermethrin-induced plasma membrane perturbation on erythrocytes from rats: reduction of fluidity in the hydrophobic core and in glutathione peroxidase activity

The effects of treatment with the synthetic insecticide cypermethrin on plasma membrane fluidity, lipid peroxidation and antioxidant status in rat erythrocytes were investigated. Rats were treated by gavage with a low dose (12.5 mg/kg body weight per day) of cypermethrin in corn oil for 60 days. DPH and TMA-DPH fluorescence anisotropy experiments show that cypermethrin treatment, compared with controls, induced a significant decrease in erythrocyte membrane fluidity measured by DPH, while no changes were observed using TMA-DPH. Cypermethrin treatment also induced a significant increase in the lipid peroxidation, measured by the formation of conjugated dienes. The increased oxidative stress resulted in a significant decrease in the activity of glutathione peroxidase. The results are discussed in terms of preferential localization of cypermethrin in the hydrophobic core of the membrane, where it increases lipid packing and consequently decreases membrane fluidity.

Effects of early life permethrin exposure on spatial working memory and on monoamine levels in different brain areas of pre-senescent rats.

Pesticide exposure during brain development could represent an important risk factor for the onset of neurodegenerative diseases. Previous studies investigated the effect of permethrin (PERM) administered at 34 mg/kg, a dose close to the no observable adverse effect level (NOAEL) from post natal day (PND) 6 to PND 21 in rats. Despite the PERM dose did not elicited overt signs of toxicity (i.e. normal body weight gain curve), it was able to induce striatal neurodegeneration (dopamine and Nurr1 reduction, and lipid peroxidation increase). The present study was designed to characterize the cognitive deficits in the current animal model. When during late adulthood PERM treated rats were tested for spatial working memory performances in a T-maze-rewarded alternation task they took longer to choose for the correct arm in comparison to age matched controls. No differences between groups were found in anxiety-like state, locomotor activity, feeding behavior and spatial orientation task. Our findings showing a selective effect of PERM treatment on the T-maze task point to an involvement of frontal cortico-striatal circuitry rather than to a role for the hippocampus. The predominant disturbances concern the dopamine (DA) depletion in the striatum and, the serotonin (5-HT) and noradrenaline (NE) unbalance together with a hypometabolic state in the medial prefrontal cortex area. In the hippocampus, an increase of NE and a decrease of DA were observed in PERM treated rats as compared to controls. The concentration of the most representative marker for pyrethroid exposure (3-phenoxybenzoic acid) measured in the urine of rodents 12 h after the last treatment was 41.50 μg/L and it was completely eliminated after 96 h.

Codrugs linking L-dopa and sulfur-containing antioxidants: new pharmacological tools against Parkinson's disease.

A series of multifunctional codrugs (1-6) were synthesized to overcome the pro-oxidant effect associated with L-dopa (LD) therapy. Target compounds release LD and dopamine (DA) in human plasma after enzymatic hydrolysis, displaying an antioxidant effect superior to that of N-acetylcysteine (NAC). After intracerebroventricular injection of codrug 4, the levels of DA in the striatum were higher than those in LD-treated groups, indicating that this compound has a longer half-life in brain than LD.

Effect of permethrin plus antioxidants on locomotor activity and striatum in adolescent rats

Pyrethroids are important insecticides used largely because of their high activity as an insecticide and their low mammalian toxicity. Some studies have demonstrated that these products show neurotoxic effects on the mammalian central nervous system. The aim of the present study was to investigate the propensity of permethrin to induce oxidative stress in adolescent rats and its possible attenuation by Vitamin E alone or+Coenzyme Q(10). Data indicated that adolescent rats exposed to permethrin exhibited alteration in the locomotor activity and plasma membrane fluidity of striatum. Vitamin E+Q(10) and Vitamin E alone supplementation reversed the negative effect on central nervous system. Permethrin alteration of striatum plasma membrane fluidity was restored by Vitamin E+Q(10). Data obtained from red blood cells showed that permethrin did not induce any modification of plasma membrane fluidity in adolescent rats, whereas antioxidants supplementation induced pro-oxidant effect. In summary some differences between antioxidant treatments were observed at striatum level: Coenzyme Q(10)+Vitamin E maintains plasma membrane fluidity, while Vitamin E is more effective to preserve GSH level.

The impact of early life permethrin exposure on development of neurodegeneration in adulthood.

Early life environmental exposure to pesticides could play a critical role in the onset of age-related diseases. The present study aims to evaluate in brain, plasma and leukocytes of 300 day-old rats, the effect of a low dose of the insecticide permethrin administered during early life (1/50 LD(50), from 6th to 21st day of life). The outcomes show that Nurr1, mRNA and protein expression, as well as calcium and NO levels are decreased in striatum. Moreover, the pesticide induces an imbalance in glutamate, calcium and NO in hippocampus. Low calcium concentrations in leukocytes and in plasma were observed, while increased NO and decreased SOD plasma levels were measured. The results suggest that permethrin intake at a dose close to the NOAEL (25 mg/kg) during the perinatal period can interact with Nurr1 by reducing its expression on striatum nucleus. Consequently, the maintenance of dopaminergic neurons as well as Nurr1 inhibitory effect on the production of proinflammatory mediators fails. The changes in biological markers found in our animal model could represent the basis to study neurodegenerative diseases whose development depends on individual gene signature and life style.

Ibuprofen and Lipoic Acid Diamides as Potential Codrugs with Neuroprotective Activity

Current evidences support the hypothesis that non‐steroidal anti‐inflammatory drugs (NSAIDs) and antioxidant therapy might protect against the development of Alzheimers disease (AD). In the present work, our attention was focused on ibuprofen (IBU) used in clinical trails to prevent Alzheimers disease, and (R)‐α‐lipoic acid (LA) considered as a potential neuroprotective agent in AD therapy. In particular, we investigated a series of lipophilic molecular combinations obtained by joining (R)‐α‐lipoic acid and ibuprofen via an amide bond. These new entities might allow targeted delivery of the parent drugs to neurons, where cellular oxidative stress and inflammation seem related to Alzheimers disease. Our study included the synthesis of conjugates 1–3 and the evaluation of their physicochemical and in‐vitro antioxidant properties. The new compounds are extremely stable in aqueous buffer solutions (pH = 1.3 and 7.4), and in rat and human plasma they showed a slow bioconversion to ibuprofen and (R)‐α‐lipoic acid. Codrugs 1–3 displayed in vitro free radical scavenging activity and were hydrolyzed more rapidly in brain tissue than in rat serum indicating that these new entities might allow targeted delivery of the parent drugs to neurons. The immunohistochemical analysis of Aβ (1‐40) protein showed that Aβ‐injected cerebral cortices treated with ibuprofen or compound 1 showed few plaques within capillary vessels and, in particular, Aβ (1‐40) protein was less expressed in codrug‐1‐treated than in ibuprofen‐treated cerebral cortex.

Ibuprofen and Glutathione Conjugate as a Potential Therapeutic Agent for Treating Alzheimer's Disease

Non‐steroidal anti‐inflammatory drugs (NSAIDs) and antioxidant therapy might protect against the development of Alzheimers disease (AD). In the present work, we synthesized a molecular combination of glutathione (GSH) and ibuprofen (IBU) via an amide bond and investigated its potential for targeted delivery of the parent drugs to neurons, where cellular oxidative stress and inflammation are related to AD. Evaluation of its physicochemical and in‐vitro antioxidant properties indicated that compound 1 exhibits good stability toward human plasma enzymatic activity, and, like GSH, displays in‐vitro free radical scavenging activity in a time and concentration‐dependent manner. The new compound was also assessed by infusion in a rat model for Alzheimers disease for its potential to antagonize the deleterious structural and cognitive effects of β‐amyloid(1‐40). In behavioral tests of long‐term spatial memory, animals treated with codrug 1 performed significantly better than those treated with β‐amyloid (Aβ) peptide. Histochemical findings confirmed the behavioral data, revealing that Aβ protein was less expressed in cerebral cortex treated with 1 than that treated with IBU. Taken together, the present findings suggest that conjugate 1 treatment may protect against the oxidative stress generated by reactive oxygen species (ROS) and the cognitive dysfunction induced by intracerebroventricular (i.c.v.) infusion of Aβ(1‐40) in rats, and thus that codrug 1 could prove useful as a tool for controlling AD induced cerebral amyloid deposits and behavioral deterioration.

Early life permethrin insecticide treatment leads to heart damage in adult rats

Early life environmental exposure to xenobiotics could represent a critical period for the onset of permanent alterations in the structure and function of different organs. Cardiovascular diseases can be related to various factors including environmental toxicants. The aim of the present study was to evaluate the effect of early life permethrin treatment (1/50 LD(50), from 6th to 21st day of life) on heart of adult rats. Increased DNA damage, decreased heart cell membrane fluidity, increased cholesterol content, protein and lipid oxidation were measured in heart cells from adult rats treated with permethrin during the neonatal period with respect to control rats. Moreover, the same group showed higher levels of cholesterol, IL-1β, IL-2, IFN-γ, rat-Rantes and IL-10 cytokines and decreased albumin content in plasma. Lower cholesterol levels and perturbation in the phospholipid lateral diffusion together with decreased GSH levels and increased GPx activity were measured in heart mitochondria of the treated group. Our findings support the evidence that the neonatal period has a critical role in the development of heart disease in adulthood. We hypothesize that the alterations observed in adult rats could depend on epigenetic changes that occurred during this period which influence gene expression throughout the rats life, leading to alterations of certain parameters related to cardiac function.

The primary role of glutathione against nuclear DNA damage of striatum induced by permethrin in rats.

Pyrethroids are one of the most widely used class of insecticides and their toxicity is dominated by pharmacological actions upon the CNS. This study reports as the subchronic treatment (60 days) with permethrin (PERM) (1/10 of LD(50)) induced nuclear DNA damage in rat striatum cells. Comet assay outcomes showed that PERM produced single- and double-strand breaks in striatum cells, the DNA damage was not related to oxidation at pyrimidine and purine bases. Vitamin E (280 mg/kg body weight/day) and vitamin E+coenzyme Q(10) (10 mg/kg/3 ml) supplementation could protect PERM treated rats against nuclear DNA damage. With the aim to evaluate the cause of nuclear DNA damage observed in striatum of rat treated with PERM, in vitro studies on striatum submitochondrial particles (SMPs) and on striatum cells treated with 10 muM PERM alone or plus 16 or 32 nM GSH were performed. SMPs incubated with PERM showed a decrease in superoxide anion release from the electron transport chain by inhibition of mitochondrial complex I. The effect could be related to the decrease of membrane fluidity measured in the hydrophilic-hydrophobic region of the mitochondrial membrane. This result discarded the involvement of the mitochondrial reactive oxygen species in the nuclear DNA damage. On the contrary, GSH played a crucial role on striatum since it was able to protect the cells against nuclear DNA damage induced by PERM. In conclusion our outcomes suggested that nuclear DNA damage of striatum cells was directly related to GSH depletion due to PERM insecticide.

New L‐Dopa Codrugs as Potential Antiparkinson Agents

This paper reports the synthesis and preliminary evaluation of new L‐dopa (LD) conjugates (1 and 2) obtained by joining LD with two different natural antioxidants, caffeic acid and carnosine, respectively. The antioxidant efficacy of compounds 1 and 2 was assessed by evaluating plasmatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the rat. Rat striatal concentration of LD and dopamine (DA), and central nervous effects were evaluated after oral administration of the codrugs 1 and 2. The results suggest that, though our codrugs are devoid of significant antioxidant activity, they are able to induce sustained delivery of DA in rat striatum and can improve LD and DA release in the brain.