Effects of diazinon on acetylcholinesterase activity and lipid peroxidation in the brain of Oreochromis niloticus

The aim of this study was to investigate the effects of organophosphorus (OP) pesticide diazinon on acetylcholinesterase (AChE: EC 3.1.1.7) activity and its relationship to lipid peroxidation (LPO) in the brain of a freshwater fish, Oreochromis niloticus. Malondialdehyde (MDA) content was used as biomarker for LPO. Fish were exposed to 1 and 2 mg/L sublethal concentrations of diazinon for 1, 7, 15 and 30 days. In the entire experimental group, AChE activity in brain significantly decreased (up to 93% of control), whereas MDA content decreased after 1 day, and increased after 7 and 15 days of exposures. MDA was in similar level with the control group after diazinon exposure of 30 days. The findings of the present study show that diazinon inhibited AChE activity and it has LPO-inducing potential in fish. The inhibition of AChE activity in the brain of O. niloticus correlated with increased MDA levels after 7 and 15 days diazinon exposures (r = −0.661, P < 0.019; r = −0.652, P < 0.022, respectively).     

Diazinon alters sperm chromatin structure in mice by phosphorylating nuclear protamines

Organophosphorus (OP) pesticides, widely used in agriculture and pest control, are associated with male reproductive effects, including sperm chromatin alterations, but the mechanisms underlying these effects are unknown. The main toxic action of OP is related to phosphorylation of proteins. Chemical alterations in sperm nuclear proteins (protamines), which pack DNA during the last steps of spermatogenesis, contribute to male reproductive toxicity. Therefore, in the present study, we tested the ability of diazinon (DZN), an OP compound, to alter sperm chromatin by phosphorylating nuclear protamines. Mice were injected with a single dose of DZN (8.12 mg/kg, i.p.), and killed 8 and 15 days after treatment. Quality of sperm from epididymis and vas deferens was evaluated through standard methods and chromatin condensation by flow cytometry (DNA Fragmented Index parameters: DFI and DFI%) and fluorescence microscopy using chromomycin-A(3) (CMA(3)). Increases in DFI (15%), DFI% (4.5-fold), and CMA(3) (2-fold) were observed only at 8 days post-treatment, indicating an alteration in sperm chromatin condensation and DNA damage during late spermatid differentiation. In addition, an increase of phosphorous content (approximately 50%) in protamines, especially in the phosphoserine content (approximately 73%), was found at 8 days post-treatment. Sperm viability, motility, and morphology showed significant alterations at this time. These data strongly suggest that spermatozoa exposed during the late steps of maturation were the targets of DZN exposure. The correlation observed between the phosphorous content in nuclear protamines with DFI%, DFI, and CMA(3) provides evidence that phosphorylation of nuclear protamines is involved in the OP effects on sperm chromatin.     

Effects of Deliberate Ingestion of Organophosphate or Paraquat on Brain Stem Auditory-Evoked Potentials

Organophosphate (OP) and paraquat (PQ) ingestion is a serious health problem. A common pathology behind OP or PQ poisoning is the generation of reactive oxygen species (ROS) which is known to cause ototoxicity. The aim of the study was to identify the effects of deliberate ingestion of OP or PQ on brain stem auditory-evoked potentials (BAEPs). Consecutive patients with deliberate self-poisoning with OP or PQ who were admitted to a secondary and a tertiary care hospital in the Southern province of Sri Lanka and matched controls were recruited. BAEPs were performed at 1 week (first assessment) and 6 weeks (second assessment) after the exposure. Interpeak latencies of I–III, III–V, and I–V were measured. There were 70 and 28 patients in the OP and PQ arms with the mean age of 32 ± 12 and 29 ± 12 years, respectively. There were 70 controls and their mean age was 33 ± 12 years. In OP and PQ poisoning, 53/70 and 18/28 came for the second assessment, respectively. The interpeak latency was not statistically different in the controls vs the first assessment, controls vs the second assessment, and the first vs the second assessment. There were no significant lesions in the auditory pathway in OP or PQ poisoned patients. The generation of ROS within the perilymphatic space following the ingestion of OP or PQ may not be sufficient to cause lesions in the auditory pathway. Further studies with the assessment of auditory threshold are needed.     

Diazinon and diazoxon impair the ability of astrocytes to foster neurite outgrowth in primary hippocampal neurons

Evidence from in vivo and epidemiological studies suggests that organophosphorus insecticides (OPs) are developmental neurotoxicants, but possible underlying mechanisms are still unclear. Astrocytes are increasingly recognized for their active role in normal neuronal development. This study sought to investigate whether the widely-used OP diazinon (DZ), and its oxygen metabolite diazoxon (DZO), would affect glial–neuronal interactions as a potential mechanism of developmental neurotoxicity. Specifically, we investigated the effects of DZ and DZO on the ability of astrocytes to foster neurite outgrowth in primary hippocampal neurons. The results show that both DZ and DZO adversely affect astrocyte function, resulting in inhibited neurite outgrowth in hippocampal neurons. This effect appears to be mediated by oxidative stress, as indicated by OP-induced increased reactive oxygen species production in astrocytes and prevention of neurite outgrowth inhibition by antioxidants. The concentrations of OPs were devoid of cytotoxicity, and cause limited acetylcholinesterase inhibition in astrocytes (18 and 25% for DZ and DZO, respectively). Among astrocytic neuritogenic factors, the most important one is the extracellular matrix protein fibronectin. DZ and DZO decreased levels of fibronectin in astrocytes, and this effect was also attenuated by antioxidants. Underscoring the importance of fibronectin in this context, adding exogenous fibronectin to the co-culture system successfully prevented inhibition of neurite outgrowth caused by DZ and DZO. These results indicate that DZ and DZO increase oxidative stress in astrocytes, and this in turn modulates astrocytic fibronectin, leading to impaired neurite outgrowth in hippocampal neurons.     

Modulation of Fenthion-Induced Oxidative Effects by BSO in the Liver of Cyprinus carpio L

The objective of the present study was to evaluate the oxidative stress potential of low-level organophosphate fenthion exposure with the modulatory effect of buthionine sulfoximine in the liver of Cyprinus carpio L. The fish were exposed to 20% of 96-hour LC₅₀ of fenthion for 24 and 96 hours. Total and oxidized glutathione, thiobarbituric acid reactive substances, protein levels, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, superoxide dismutase, and catalase-specific enzyme activities were measured spectrophotometrically. There was a 15-day depuration period to evaluate the changes in the studied parameters. Fenthion caused a time-dependent depletion of the total and reduced glutathione levels. The oxidized/reduced glutathione ratio and catalase specific enzyme activity were reduced while the glutathione-S-transferase activity was elevated. Intraperitonal buthionine sulfoximine application disclosed the inhibitory effect of fenthion on superoxide dismutase and glutathione peroxidase activities, whereas glutathione-S-transferase activity was increased. There was no change in lipid peroxidation levels during the experiments. No amelioration was observed in the affected parameters except the glutathione-S-transferase activity in the 15-day depuration period. In conclusion, glutathione-S-transferase and catalase enzyme activities and total and reduced glutathione levels were better estimators to monitor the effects of fenthion in low concentration in the liver of C. carpio. The depuration period was not adequate to recover the antioxidant capacity.     

Effects of chlorpyrifos on the metabolome of the freshwater carp,Cyprinus Carpio

This study investigated the effects of waterborne chlorpyrifos with concentrations of 1 and 100 µg/L for L and H‐groups, respectively, on metabolome profiles of carp plasma using ¹H‐NMR. Principal component analysis suggests that chlorpyrifos exposure firstly affected in L and H‐groups on day 2 or 4, and followed a second effect in both exposure groups on day 14. Levels of metabolites related to the energy production in the body, such as glucose, glycerol, valine, leucine, isoleucine, lactate, alanine, 3‐D‐hydroxybutyrates and acetoacetate, significantly changed by exposures of chlorpyrifos. Those results suggest that energy production was severely affected in carp. The exposure could also be highly elevated ammonia levels especially in H‐group due to severe convulsion in muscle caused by the inhibition of acetylcholinesterase activity. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 253–260, 2015.     

Sublethal toxicity of quinalphos on oxidative stress and antioxidant responses in a freshwater fish Cyprinus carpio

Extensive use of quinalphos, an organophosphorus pesticide, is likely to reach the aquatic environment and thereby posing a health concern for aquatic organisms. Oxidative stress and antioxidant responses may be good indicators of pesticide contamination in aquatic organisms. The data on quinalphos induced oxidative stress and antioxidant responses in carps are scanty. This study is aimed to assess the two sublethal concentrations of quinalphos (1.09 and 2.18 μL L^?1) on oxidative stress and antioxidant responses of Cyprinus carpio for a period of 20 days. In liver, the malondialdehyde level was found to be significantly increased in both the concentrations. The results of the antioxidant parameters obtained show a significant increase in superoxide dismutase, catalase, and glutathione‐S‐transferase activity in liver of fish. These results demonstrate that environmentally relevant levels of the insecticide quinalphos can cause oxidative damage and increase the antioxidant scavenging capacity in C. carpio. This may reflect the potential role of these parameters as useful biomarkers for the assessment of pesticide contamination. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1399–1406, 2016.     

Mechanisms of Inhibitory Effects of Breviscapine on Lipid Peroxidation in Rat Brain Mitochondria

本文研究了灯盏花素抑制脂质过氧化的作用机制。大鼠脑线粒体脂质过氧化物用硫代巴比妥酸比色法测定。灯盏花素与铁的螯合活性用差示光谱法测定。黄嘌呤黄嘌呤氧化酶（ＸａｎＸＯ）体系产生的超氧阴离子自由基（Ｏ２）及ＦｅＳＯ４Ｈ２Ｏ２体系产生的羟自由基（·ＯＨ）用比色法测定。结果表明：灯盏花素能有效地抑制ＸａｎＸＯ和ＦｅＳＯ４Ｈ２Ｏ２诱导的脑线粒体脂质过氧化反应，其ＩＣ５０分别为９３０１和６２１８μｍｏｌ·Ｌ－１。灯盏花素也能清除ＸａｎＸＯ体系产生的Ｏ２和ＦｅＳＯ４Ｈ２Ｏ２体系产生的·ＯＨ，其ＩＣ５０分别为３２６３和２０２２μｍｏｌ·Ｌ－１。灯盏花素还具有螯合Ｆｅ２＋的活性。由此可见，灯盏花素是在氧自由基与线粒体膜的反应中（１）·ＯＨ的形成（通过与Ｆｅ２＋螯合）（２）脂质过氧化的启动（通过清除Ｏ２和·ＯＨ）两个环节抑制脂质过氧化反应的。清除氧自由基和与Ｆｅ２＋螯合是灯盏花素抑制脑线粒体脂质过氧化的作用机制     

纳洛酮对大鼠局灶性脑缺血再灌注损伤的影响及其机制研究

目的 :观察不同剂量的纳洛酮对大鼠局灶性脑缺血再灌注损伤模型的影响 ,并探讨其保护作用机制。方法 :将大鼠随机分为假手术组、模型组、纳络酮 (低、中、高剂量 )组和阳性对照组 (尼莫地平 ) ,采用改良的Longa法建立大鼠局灶性脑缺血再灌注损伤模型。各组腹腔注射给药结束后对大鼠神经功能进行评分 ,测量其脑梗塞面积、超氧化物歧化酶 (SOD )活性及丙二醛 (MDA)含量 ,并用电子显微镜观察脑组织超微结构变化。结果 :造模后 ,大鼠神经行为评分值升高 ,梗塞面积扩大 ,血清SOD活性降低 ,MDA含量增加 ,脑组织病理结构和超微结构明显受损。应用不同剂量的纳洛酮后均能改善上述指标。结论 :纳洛酮对大鼠局灶性脑缺血再灌注损伤模型具有保护作用 ,机制可能与其抑制脂质过氧化反应有关。     

Effects of high fat fish oil and high fat corn oil diets on initiation of AOM-induced colonic aberrant crypt foci in male F344 rats

Modulating effects of high fat fish oil (HFFO) and high fat corn oil (HFCO) diets on azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) were studied in male F344 rats following 8 weeks of dietary treatment. The incidence of AOM-induced ACF was significantly lower in the proximal colon of rats fed the HFFO diets compared with rats fed the HFCO diets. No differential effects were found on enzyme activities that are involved in metabolic activation and detoxification of AOM. Activities of hepatic P450 IAI and P450 IIBI and hepatic and feacal levels of lipid peroxidation were increased by feeding the HFFO diet. Hepatic GST activity and plasma levels of PGE₂ were significantly lower in rats fed the HFFO diets compared with those fed the HFCO diets. These observations demonstrate that HFFO diets with high levels of n-3 PUFAs are also protective against preneoplastic lesions in the early stages of chemically induced colon carcinogenesis. It seems unlikely from our results that the inhibitory effect of a HFFO diet can be attributed to an altered metabolic activation and detoxification of AOM. Other mechanisms such as oxidative stress or reduction of PGE₂ levels may play an important role in the anticarcinogenic effects of n-3 PUFAs.     

Pharmacokinetic and pharmacodynamic interaction for a binary mixture of chlorpyrifos and diazinon in the rat

Chlorpyrifos (CPF) and diazinon (DZN) are two commonly used organophosphorus (OP) insecticides and a potential exists for concurrent exposures. The primary neurotoxic effects from OP pesticide exposures result from the inhibition of acetylcholinesterase (AChE). The pharmacokinetic and pharmacodynamic impact of acute binary exposures of rats to CPF and DZN was evaluated in this study. Rats were orally administered CPF, DZN, or a CPF/DZN mixture (0, 15, 30, or 60 mg/kg) and blood (plasma and RBC), and brain were collected at 0, 3, 6, 12, and 24 h postdosing, urine was also collected at 24 h. Chlorpyrifos, DZN, and their respective metabolites, 3,5,6-trichloro-2-pyridinol (TCP) and 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMHP), were quantified in blood and/or urine and cholinesterase (ChE) inhibition was measured in brain, RBC, and plasma. Coexposure to CPF/DZN at the low dose of 15/15 mg/kg did not alter the pharmacokinetics of CPF, DZN, or their metabolites in blood. A high binary dose of 60/60 mg/kg increased the C(max) and AUC and decreased the clearance for both parent compounds, likely due to competition between CPF and DZN for CYP450 metabolism. At lower doses, most likely to be encountered in occupational or environmental exposures, the pharmacokinetics were linear. A dose-dependent inhibition of ChE was noted in tissues for both the single and coexposures, and the extent of inhibition was plasma > RBC > or = brain. The overall relative potency for ChE inhibition was CPF/DZN > CPF > DZN. A comparison of the ChE response at the low binary dose (15/15 mg/kg), where there were no apparent pharmacokinetic interactions, suggested that the overall ChE response was additive. These experiments represent important data concerning the potential pharmacokinetic and pharmacodynamic interactions for pesticide mixtures and will provide needed insight for assessing the potential cumulative risk associated with occupational or environmental exposures to these insecticides.     

超声乳化术中超声波对兔视网膜的影响

目的从脂质过氧化的角度探讨超声乳化术中治疗剂量的超声波对兔视网膜的影响。方法选取青紫蓝兔60只(120只眼),将兔眼分为实验组、对照组。实验组行超声乳化术,对照组行晶体囊外摘除术,各组分别在术毕,术后6、24 h剥离视网膜。测定视网膜中谷胱甘肽过氧化物酶(GSH-Px)活性、超氧化物歧化酶(SOD)活性、脂质过氧化物(LPO)的含量。结果不同时点实验组各指标与对照组比较:①实验组GSH-Px活性在各时点均低于对照组,两组间的差异均有统计学意义(P<0.05);②实验组SOD活性在各时点均低于对照组,术毕两组间的差异有统计学意义(P<0.05),术后6、24 h两组间的差异无统计学意义(P>0.05);③实验组LPO含量在各时点均高于对照组,两组间的差异均有统计学意义(P<0.01)。结论从脂质过氧化的角度,超声乳化术中的治疗剂量的超声波对兔视网膜可造成一定程度的损伤,在术后24 h没有完全恢复,超声乳化术中应控制使用超声波的能量和时间。     

Toxic effects of diazinon and its photodegradation products

The toxic effects of diazinon and its irradiated solutions were investigated using cultivated human blood cells (lymphocytes and erythrocytes) and skin fibroblasts. Ultra Performance Liquid Chromatography (UPLC)–UV/VIS system was used to monitor the disappearance of starting diazinon during 115-min photodegradation and formation of its by-products (diazoxon and 2-isopropyl-6-methyl-4-pyrimidinol (IMP)) as a function of time. Dose-dependent AChE and Na⁺/K⁺-ATPase inhibition by diazinon was obtained for all investigated cells. Calculated IC₅₀ (72 h) values, in M, were: 7.5 × 10⁻⁶/3.4 × 10⁻⁵, 8.7 × 10⁻⁵/6.6 × 10⁻⁵, and 3.0 × 10⁻⁵/4.6 × 10⁻⁵ for fibroblast, erythrocyte and lymphocyte AChE/Na⁺/K⁺-ATPase, respectively. Results obtained for reference commercially purified target enzymes indicate similar sensitivity of AChE towards diazinon (IC₅₀ (20 min)-7.8 × 10⁻⁵M), while diazinon concentrations below 10 mM did not noticeably affect Na⁺/K⁺-ATPase activity. Besides, diazinon and IMP induced increasing incidence of micronuclei (via clastogenic mode of action) in a dose-dependent manner up to 2 × 10⁻⁶ M and significant inhibition of cell proliferation and increased level of malondialdehyde at all investigated concentrations. Although after 15-min diazinon irradiation formed products do not affect purified commercial enzymes activities, inhibitory effect of irradiated solutions on cell enzymes increased as a function of time exposure to UV light and resulted in significant reduction of AChE (up to 28–45%) and Na⁺/K⁺-ATPase (up to 35–40%) at the end of irradiation period. Moreover, photodegradation treatment strengthened prooxidative properties of diazinon as well as its potency to induce cytogenetic damage.     

Sublethal Effects of Profenofos on Locomotor Behavior and Gill Architecture of the Mosquito Fish,Gambusia affinis

Subacute studies of profenofos on mosquito fish, Gambusia affinis, were carried out for 20 days to assess the locomotor behavior and structural integrity of gill in relation to bioaccumulation and targeted enzyme acetylcholinesterase (AChE; EC 3.1.1.7). The sublethal concentration of 0.13 mg/L (1/5 of LC₅₀) altered locomotor behavior such as distance traveled and swimming speed in exposed fish. This could be due to inhibition in the activity of acetylcholinesterase and deformities in the primary and secondary lamella of gill. The bioaccumulation values indicated that the accumulation of profenofos was highest in viscera followed by head and body. The average bioconcentration factor values are 254.83, 6.18, and 2.52 μg/g for viscera, head, and body. The findings revealed that profenofos is highly toxic even at sublethal concentrations to the mosquito fish, Gambusia affinis.     

Diazinon oxon affects the differentiation of mouse N2a neuroblastoma cells

The aim of this study was to assess the neurotoxicity of diazinon oxon (DZO), a major in vivo metabolite of the phosphorothionate insecticide diazinon (DZ), on differentiating mouse N2a neuroblastoma cells. When used at concentrations of 1, 5 and 10 μM, DZO did not cause cell death but it impaired the outgrowth of axon-like processes after 24 h. Densitometric scanning of Western blots of lysates of N2a cells revealed that exposure to 5 or 10 μM DZO for 24 h increased the expression of phosphorylated neurofilament heavy chain (NFH) compared to controls, while there was no significant change in total NFH. By contrast, treatment of N2a cells with 1–10 μM DZO resulted in marked reductions in the expression of the axon growth-associated protein GAP-43. DZO-treated cells also showed an increased expression of the heat shock protein HSP-70 compared to controls. The above biochemical changes were not temporally related to inhibition of acetylcholinesterase (AChE). These data suggest that biologically relevant, subcytotoxic levels of DZO may exert neurotoxic effects on differentiating cells and that the mechanisms involved are different from those attributed to its parent compound.     

Sublethal effects of organophosphate diazinon on the brain of Cyprinus carpio

Effects of diazinon, at different concentrations and exposure times, were investigated in freshwater fish, Cyprinus carpio, to elucidate the possible mode of action on lipid peroxidation together with the inhibitory effect of diazinon on acetylcholinesterase activity and changes in tissue protein levels. Cholinesterase inhibition is considered to be a specific biomarker of exposure to organophosphorus pesticides. Fish were exposed to 0.0036 microg/L, 0.018 microg/L, and 0.036 microg/L (sublethal) concentrations of diazinon for 5, 15, and 30 days, and biochemical measurements were carried out spectrophotometrically. Brain was chosen as an indicator tissue because it is a target system for the organophosphorus action. More than 20% decline in acetylcholinesterase activity relative to mean activity of the controls was observed in the diazinon-exposed groups. Protein content decreased significantly after 15 days of exposure to 0.018 microg/L and 0.036 microg/L diazinon and after 30 days of exposure to 0.036 microg/L. Malondialdehyde level declined markedly compared with the control levels. This study showed that prolonged exposures of C. carpio to diazinon had significant effects on brain acetylcholinesterase activity and that environmentally relevant concentrations of diazinon can significantly inhibit brain acetylcholinesterase activity. Altered protein content was probably due to the high energy demand under pesticide stress or inhibition of de novo enzyme synthesis. The decreased malondialdehyde content may reflect the possibility of better protection against oxidative stress.     

Methods for the estimation of acetylcholinesterase activity in the erythrocytes of laboratory animals given carbamates or organophosphorus compounds

This report describes the modifications necessary to adapt the pH stat and a pH method for the estimation of acetylcholinesterase activity in the erythrocytes of various species of laboratory animals. Both methods were evaluated in studies in which cholinesterase inhibitors, carbamates and Organophosphorus compounds, were given to the animals.     

Effects of various plant polyphenols on bladder carcinogen benzidine-induced mutagenicity.

Benzidine (Bz), a human bladder carcinogen, was strongly mutagenic to Salmonella TA102 tester strain in the Ames Salmonella microsome/mutagenicity assay in the presence of rat liver S9 mix. Various non-mutagenic plant polyphenols were included in the assay to test their inhibitory effects on the Bz-induced mutations. Coumestrol, ellagic acid (EA), (-)-epicatechin (EC), (-)-epichatechingallate (ECG), gallic acid (GA), (-)-gallocatechin (GC), plumbagin, propyl gallate (PG), taxifolin, and 2,2',4'-trihydroxychalcone were found to have a strong inhibitory effect on Bz-induced mutations. (-)-Epigallo-catechingallate (EGCG), fisetin, (-)-gallocatechingallate (GCG), and piceatannol were moderately inhibitory to the mutations; whereas, (-)-catechin, (-)-catechingallate (CG), and reseveratrol were weakly inhibitory to the mutations. (-)-Epigallocatechin (EGC) and 7,3',4'-trihydroxy isoflavon were not inhibitory to the Bz-induced mutations. Isoliquirtigenin, quercetin dihydrate, and rhein were found to be mutagenic in tester strain TA102. Benzidine mediated lipid peroxidation was conducted employing the thiobarbituric acid reactive substances (TBARS) assay using linoleic acid as a substrate. In the presence of rat liver S9 mix, Bz could cause lipid peroxidation as an outcome of production of oxygen free radicals. Incorporation of the above mentioned non-mutagenic plant polyphenols significantly inhibited benzidine mediated lipid peroxidation in a time dependent manner. These polyphenols also effectively reduced the iron mediated lipid peroxidation. Thus, it is concluded that the inhibition of oxidative mutagenicity of Bz by plant polyphenols could be due to an inhibitory effect of plant polyphenols on the bioactivating enzymes such as cytochrome P-450 and peroxidase and the chelation of iron present in the cytochrome P-450 in the S9 mix. Thus, these plant polyphenols play a significant inhibitory role on Bz-induced mutagenicity.     

Effect of silymarin on biochemical parameters of oxidative stress in aged and young rat brain

Silymarin (SM), the active complex of milk thistle, is a lipophilic fruit extract and is composed of several isomer flavonolignans. Flavonoids are antioxidants found molecules capable of intercepting reactive oxygen species (ROS). The oxidative stress (OS) is caused by imbalance between antioxidant defenses and production of ROS causing oxidative damage to macromolecules. Brain is susceptible to oxidative stress and it is associated with age-related brain dysfunction. This study evaluated the effect of SM on biochemical parameters that evaluate OS in aged and young rat brain. For measures of OS were used measures of total oxyradical scavenging capacity (ACAP) through the concentration of ROS by fluorescence, lipid peroxidation (LPO), via FOX and TBARS, proteins oxidation by Western blot (WB). Rats were treated with SM at doses of 200 and 400 mg/kg/day (SM200 and SM400). The LPO analyzed through FOX was increased in the hippocampus of aged animals treated with SM400, but in the cortex of young and aged, the highest dose of SM decreased LPO analyzed through TBARS. Both doses have seemed most effective in the reduction of oxidized proteins in aged brain. These results suggest that SM may contribute to the prevention of aged-related and pathological degenerative processes in the brain.