Effect of sulfite on cognitive function in normal and sulfite oxidase deficient rats

Sulfites, which are commonly used as preservatives, are continuously formed in the body during metabolism of sulfur-containing amino acids. Sulfite is oxidized to sulfate ion by sulfite oxidase (SOX, EC. 1.8.3.1). The aim of this study was to investigate the possible toxic effects of sulfite on neurons by measuring active avoidance learning in normal and SOX-deficient rats. For this purpose, male albino rats used in this study were divided into eight groups such as control group (C), sulfite group (25 mg/kg) (S), vitamin E group (50 mg/kg) (E), sulfite (25 mg/kg)+vitamin E group (50 mg/kg) (SE), SOX-deficient group (D), deficient+vitamin E group (50 mg/kg) (DE), deficient+sulfite group (25 mg/kg) (DS) and deficient+sulfite (25 mg/kg)+vitamin E group (50 mg/kg) (DSE). Sulfite-induced impairment of active avoidance learning in SOX-deficient rats but not in normal rats. Sulfite had no effect on hippocampus TBARS levels in SOX normal groups. In SOX-deficient rats, TBARS levels were found to be significantly increased with sulfite exposure. Vitamin E reversed the observed detrimental effects of sulfite in the SOX-deficient rats on their hippocampal TBARS but not on their active avoidance learning. In conclusion, sulfite has neurotoxic effects in sulfite oxidase deficient rats, but this effect may not depend on oxidative stress.     

Expressions of N-methyl-d-aspartate receptors NR2A and NR2B subunit proteins in normal and sulfite-oxidase deficient rat’s hippocampus: effect of exogenous sulfite ingestion

Sulfites whether ingested or produced through the sulfur-containing amino acids metabolism of the animal are very active molecules and can cause cellular toxicity. Sulfite oxidase (SOX), a heme- and molybdenum containing mitochondrial enzyme, prevents mammalian cells from adverse effects of sulfite toxicity by metabolizing sulfite to sulfate. The present study was aimed to investigate effect of sulfite on the N-methyl-d-aspartate (NMDA) receptor (NMDAR) NR2A and NR2B subunits in hippocampus of normal and SOX-deficient rats. Rats were divided into four groups; (1) control group, which was given rat chow and tap water ad libitum (C), (2) sulfite group, treated with sulfite (25 mg/kg) in drinking water and commercial rat chow ad libitum (S), (3) SOX-deficient group, maintained on high-W/Mo-deficient regimen to produce SOX deficiency (D), and (4) SOX-deficient + sulfite group (DS), prepared as those in the third group and were afterwards given sulfite (25 mg/kg) additionally. Whole treatment schedule were continued for 6 weeks. Sulfite treatment caused a decrease of NR2A and NR2B subunits of the NMDAR in hippocampus of rats in S and DS groups. Interestingly, similar decrement was observed in D group, probably due to increased endogen sulfite production. In summary, the results indicated that feeding sulfite to the rats may cause down-regulation of NMDARs by degrading NR2A and NR2B subunits of it, which may be considered as a neuro-compensatory mechanism.     

The effect of ingested sulfite on active avoidance in normal and sulfite oxidase-deficient aged rats

The aim of this study was to investigate the possible toxic effects of sulfite on neurons by measuring active avoidance learning in normal and sulfite oxidase (SOX)-deficient aged rats. Twenty-four months of age Wistar rats were divided into four groups: control (C), sulfite-treated group (S), SOX-deficient group (D) and SOX-deficient?+?sulfite-treated group (DS). SOX deficiency was established by feeding rats with a low molybdenum (Mo) diet and adding 200?ppm tungsten (W) to their drinking water. Sulfite in the form of sodium metabisulfite (25?mg/kg) was given by gavage for six weeks. Active avoidance responses were determined by using an automated shuttle box. Hepatic SOX activity was measured to confirm SOX deficiency. The hippocampus was used for determining the activity of cyclooxygenase (COX) and caspase-3 enzymes and the level of prostaglandin E2 (PGE2) and nitrate/nitrite. SOX-deficient rats had an approximately 10-fold decrease in hepatic SOX activity compared with normal rats. Sulfite did not induce impairment of active avoidance learning in SOX-deficient rats and in normal rats compared with their control groups. Sulfite had no effect on the activity of COX and caspase-3 in the hippocampus. Treatment with sulfite did not significantly increase the level of PGE2 and nitrate/nitrite in the hippocampus.     

The effect of sodium metabisulfite on visual evoked potentials in rats with hypercholesterolemia

This study aimed to investigate the effects of hypercholesterolemia on visual evoked potentials (VEPs) and sulfite additional effects. Rats were assigned as follows: control (C), sulfite (S), hypercholesterolemia (H), vitamin E (E), sulfite + vitamin E (SE), hypercholesterolemia + sulfite (HS), hypercholesterolemia + vitamin E (HE), and hypercholesterolemia + sulfite + vitamin E (HSE). Hypercholesterolemic diet led significant increase in plasma cholesterol levels of rats. Brain thiobarbituric acid reactive substances (TBARS) levels were significantly increased in S, E, SE, HE and HSE groups compared with C. TBARS levels were increased in HE and HSE groups as compared to HS group. Nitrite levels were decreased in S, SE, H, HS and HSE groups compared with C. Nitrite level was notably increased in the HE group compared with H group. Sulfite exposure prolonged N1 and P3 latencies of VEP in group S compared with C. Prolonged VEP latencies by sulfite were significantly decreased by vitamin E in SE group. Cholesterol rich diet increased VEP latencies in comparison with control latencies. Sulfite gave rise to an additional increase in P3 latency in HS group compared with H group. Vitamin E-treated animals had notably shortened latencies of VEP components in HE and HSE groups according to the H and HS groups, respectively.     

The effect of sodium metabisulfite on visual evoked potentials in rats with hypercholesterolemia

This study aimed to investigate the effects of hypercholesterolemia on visual evoked potentials (VEPs) and sulfite additional effects. Rats were assigned as follows: control (C), sulfite (S), hypercholesterolemia (H), vitamin E (E), sulfite + vitamin E (SE), hypercholesterolemia + sulfite (HS), hypercholesterolemia + vitamin E (HE), and hypercholesterolemia + sulfite + vitamin E (HSE). Hypercholesterolemic diet led significant increase in plasma cholesterol levels of rats. Brain thiobarbituric acid reactive substances (TBARS) levels were significantly increased in S, E, SE, HE and HSE groups compared with C. TBARS levels were increased in HE and HSE groups as compared to HS group. Nitrite levels were decreased in S, SE, H, HS and HSE groups compared with C. Nitrite level was notably increased in the HE group compared with H group. Sulfite exposure prolonged N1 and P3 latencies of VEP in group S compared with C. Prolonged VEP latencies by sulfite were significantly decreased by vitamin E in SE group. Cholesterol rich diet increased VEP latencies in comparison with control latencies. Sulfite gave rise to an additional increase in P3 latency in HS group compared with H group. Vitamin E-treated animals had notably shortened latencies of VEP components in HE and HSE groups according to the H and HS groups, respectively.     

Final report on the safety assessment of sodium sulfite, potassium sulfite, ammonium sulfite, sodium bisulfite, ammonium bisulfite, sodium metabisulfite and potassium metabisulfite

Sodium Sulfite, Ammonium Sulfite, Sodium Bisulfite, Potassium Bisulfite, Ammonium Bisulfite, Sodium Metabisulfite, and Potassium Metabisulfite are inorganic salts that function as reducing agents in cosmetic formulations. All except Sodium Metabisulfite also function as hair-waving/straightening agents. In addition, Sodium Sulfite, Potassium Sulfite, Sodium Bisulfite, and Sodium Metabisulfite function as antioxidants. Although Ammonium Sulfite is not in current use, the others are widely used in hair care products. Sulfites that enter mammals via ingestion, inhalation, or injection are metabolized by sulfite oxidase to sulfate. In oral-dose animal toxicity studies, hyperplastic changes in the gastric mucosa were the most common findings at high doses. Ammonium Sulfite aerosol had an acute LC(50) of >400 mg/m(3) in guinea pigs. A single exposure to low concentrations of a Sodium Sulfite fine aerosol produced dose-related changes in the lung capacity parameters of guinea pigs. A 3-day exposure of rats to a Sodium Sulfite fine aerosol produced mild pulmonary edema and irritation of the tracheal epithelium. Severe epithelial changes were observed in dogs exposed for 290 days to 1 mg/m(3) of a Sodium Metabisulfite fine aerosol. These fine aerosols contained fine respirable particle sizes that are not found in cosmetic aerosols or pump sprays. None of the cosmetic product types, however, in which these ingredients are used are aerosolized. Sodium Bisulfite (tested at 38%) and Sodium Metabisulfite (undiluted) were not irritants to rabbits following occlusive exposures. Sodium Metabisulfite (tested at 50%) was irritating to guinea pigs following repeated exposure. In rats, Sodium Sulfite heptahydrate at large doses (up to 3.3 g/kg) produced fetal toxicity but not teratogenicity. Sodium Bisulfite, Sodium Metabisulfite, and Potassium Metabisulfite were not teratogenic for mice, rats, hamsters, or rabbits at doses up to 160 mg/kg. Generally, Sodium Sulfite, Sodium Metabisulfite, and Potassium Metabisulfite were negative in mutagenicity studies. Sodium Bisulfite produced both positive and negative results. Clinical oral and ocular-exposure studies reported no adverse effects. Sodium Sulfite was not irritating or sensitizing in clinical tests. These ingredients, however, may produce positive reactions in dermatologic patients under patch test. In evaluating the positive genotoxicity data found with Sodium Bisulfite, the equilibrium chemistry of sulfurous acid, sulfur dioxide, bisulfite, sulfite, and metabisulfite was considered. This information, however, suggests that some bisulfite may have been present in genotoxicity tests involving the other ingredients and vice versa. On that basis, the genotoxicity data did not give a clear, consistent picture. In cosmetics, however, the bisulfite form is used at very low concentrations (0.03% to 0.7%) in most products except wave sets. In wave sets, the pH ranges from 8 to 9 where the sulfite form would predominate. Skin penetration would be low due to the highly charged nature of these particles and any sulfite that did penetrate would be converted to sulfate by the enzyme sulfate oxidase. As used in cosmetics, therefore, these ingredients would not present a genotoxicity risk. The Cosmetic Ingredient Review Expert Panel concluded that Sodium Sulfite, Potassium Sulfite, Ammonium Sulfite, Sodium Bisulfite, Ammonium Bisulfite, Sodium Metabisulfite, and Potassium Metabisulfite are safe as used in cosmetic formulations.     

Site-specific DNA damage induced by sulfite in the presence of cobalt(II) ion. Role of sulfate radical

The reactivities of sulfite (SO23-) with DNA in the presence of metal ions were investigated by a DNA sequencing technique using 32P-labeled DNA fragments obtained from human c-Ha-ras-1 protooncogene. Sulfite caused DNA damage in the presence of Co2+, Cu2+ and Mn2+, although sulfite alone or metal ion alone did not. The order of inducing effect on sulfite-dependent DNA damage (Co2+ much greater than Cu2+ greater than Mn2+ Fe3+) was consistent with that of accelerating effect on the initial oxygen consumption rate of sulfite autoxidation. The DNA damage induced by sulfite plus Co2+ was inhibited by 3,5-dibromo-4-nitrobenzenesulfonate, primary and secondary alchols, whereas it was not inhibited by SOD, catalase and tert-butyl alcohol. Incubation of DNA with sulfite plus Co2+ followed by the piperidine treatment led to the predominant cleavage at the positions of guanine especially located 5' to guanine. Sulfite plus Cu2+ gave a DNA cleavage pattern different from that induced by sulfite plus Co2+. The photolysis of peroxydisulfate (S2O28-), which is known to produce SO-4 radicals, gave a DNA cleavage pattern similar to that induced by sulfite plus Co2+. ESR studies using spin-trapping reagent revealed the production of spin adduct possibly of SO-3 radical in a solution of sulfite plus Cu2+, whereas much less spin adduct was produced by sulfite plus Co2+. The results suggest that sulfite is rapidly autoxidized in the presence of Co2+ to produce SO4- radical causing site-specific DNA damage.     

Effect of alpha-lipoic acid on visual evoked potentials in rats exposed to sulfite

This study aimed to investigate the effect of alpha-lipoic acid (LA) administration on sulfite-induced alterations in visual evoked potentials (VEPs). Fifty two male albino Wistar rats were randomized into four experimental groups as follows; control (C), LA treated (L), sodium metabisulfite (Na(2)S(2)O(5)) treated (S), Na(2)S(2)O(5)+LA treated (SL). Na(2)S(2)O(5) (260 mg/kg/day) and LA (100 mg/kg/day) were given by intragastric intubation for 5 weeks. The latencies of VEP components were significantly prolonged in the S group and returned to control levels following LA administration. Thiobarbituric acid reactive substances (TBARS) levels in the S group were significantly higher than those detected in controls. LA significantly decreased brain and retina TBARS levels in the SL group compared with the S group. Sulfite caused a significant decrease in retina and brain glutathione peroxidase (GPx) activities which was restored to control levels via LA administration. Brain glutathione (GSH):glutathione disulfide (GSSG) ratio was significantly increased in rats jointly treated with sulfite and LA compared to rats treated with sulfite alone. Though not significant, a similar increase in GSH:GSSG ratio was also observed in the retina of SL group. This study showed that LA is protective against sulfite-induced VEP alterations and oxidative stress in the brain and retina.     

Evaluation of teratogenic potential of sodium sulfite in rats

The teratogenicity of sodium sulfite was examined in Wistar rats. The pregnant rats were fed diets containing 5, 2.5, 1.25, 0.63 or 0.32% of sodium sulfite heptahydrate(Na2SO3.7H2O) ad libitum from day 8 to 20 of pregnancy. Maternal toxicity, as evidenced by decreased body weight gain and decreased food consumption was observed at the 5% group, but no clinical signs of toxicity were observed. A significant reduction in the fetal body weight of both sexes was observed in all dose groups except 2.5% group. No significant differences in the numbers of live fetuses and intrauterine death (dead fetuses and resorptions) or sex ratios of fetuses were found between the sodium sulfite-treated and control groups. Fetal external, skeletal and internal malformations were not observed at any dose level. However, several types of skeletal and internal variations as well as delayed ossifications were observed in some groups treated with sodium sulfite, but the incidences were not significantly different from controls. Also, some fetuses with dilatation of the renal pelvis and the lateral ventricle were found in all groups except 1.25% group, but there was no dose-response. The live birth index and survival rate of offspring within 4 weeks and their body weight gain at 3 weeks after birth were not affected by sodium sulfite-treatment. In conclusion, sodium sulfite (0, 0.32, 0.63, 1.25, 2.5 or 5.0% as Na2SO3.7H2O) administered in the diet to Wistar rats during days 8-20 of pregnancy produced related signs of fetal toxicity but no evidence of teratogenicity.     

Distribution, metabolism and toxicity of inhaled sulfur dioxide and endogenously generated sulfite in the respiratory tract of normal and sulfite oxidase-deficient rats

We report on the distribution, metabolism, and toxicity of sulfite in the respiratory tract and other tissues of rats exposed to endogenously generated sulfite or to inhaled sulfur dioxide (SO2). Graded sulfite oxidase deficiency was induced in several groups of rats by manipulating their tungsten to molybdenum intake ratio. Endogenously generated sulfite and S-sulfonate compounds (a class of sulfite metabolite) accumulated in the respiratory tract tissues and in the plasma of these rats in inverse proportion to hepatic sulfite oxidase activity. In contrast to this systemic mode of exposure, sulfite exposure of normal, sulfite oxidase-competent rats via inhaled SO2 (10 and 30 ppm) was restricted to the airways. Minor pathological changes consisting of epithelial hyperplasia, mucoid degeneration, and desquamation of epithelium were observed only in the tracheas and bronchi of the rats inhaling SO2, even though the concentration of sulfite plus S-sulfonates in the tracheas and bronchi of these rats was considerably lower than that in the endogenously exposed rats. We attribute this histological damage to hydrogen ions stemming from inhaled SO2, not to the sulfite/bisulfite ions that are also a product of inhaled SO2. In addition to the lungs and trachea, all other tissues examined, except the testes, appeared to be refractory to high concentrations of endogenously generated sulfite. The testes of grossly sulfite oxidase-deficient rats were severely atrophied and devoid of spermatogenic cells.     

硒及维生素E对大鼠N_2O_4中毒性肺损伤的保护作用

目的观察补充硒(Se)与维生素E(VitE)对四氧化二氮(N2O4)致大鼠中毒性肺损伤的保护作用。方法40只Wistar大鼠被随机分成对照组、N2O4中毒组(N2O4组)、N2O4中毒+VitE组(VitE组)、N2O4中毒+Se组(Se组)、N2O4中毒+VitE+Se联合应用组(VitE+Se组)5组。使大鼠吸入N2O4(浓度352±21mg/m3,时间0.5h)复制出中毒性肺损伤模型。吸入N2O4前14dVitE组大鼠每日按200mg/(kg·bw)灌胃补充VitE;同时Se组大鼠每日按0.2mg/(kg·bw)灌胃补充Se而VitE+Se组大鼠每日按VitE200mg/(kg·bw)及Se0.2mg/(kg·bw)联合补充。中毒后3h处死大鼠,测量肺系数、血浆丙二醛(MDA)、血浆谷胱甘肽过氧化物酶(GSH-Px)、红细胞超氧化物歧化酶(SOD)以及血浆和肺内心钠素(ANP)水平。结果N2O4组大鼠的肺系数、血浆MDA及血浆ANP显著升高,血浆GSH-Px和红细胞SOD及肺内ANP明显降低。而补充VitE、Se大鼠上述指标的改变较中毒组减轻,在VitE+Se组尤其明显。结论补充VitE与Se对N2O4致大鼠中毒性肺损伤显示出有效保护作用,尤以两者联合补充效果更佳。     

The embryopathic effects of zinc deficiency and the influnce of zinc supplementation on growth and organogenesis in zinc deficient rat embroyos

BACKGROUND: Zinc deficiency during gestation is teratogenic in both humans and other mammalian species. OBJECTIVES: The objectives of this research were to investigate the embryopathic effects of zinc deficiency during the period of organogenesis and the influence of zinc supplementation of zinc deficient rats in 12 days old embryos. METHODS: There were four groups: ad libitum (C), pair-fed (PC), zinc deficient (ZD) and zinc deficient+zinc (ZDZ) groups. The ZD group received the zinc deficient liquid diet, the ZDZ group received the zinc deficient diet + 15 mg/Kg of Zinc Sulphate; and the PC group was restricted-fed the control diet, the amount consumed by the respective pair-mate in the ZD group while the group C received the liquid control diet unrestricted. RESULTS: Maternal weight-gain from days 6 to 12 of gestation were significantly lower in the zinc deficient (ZD) animals, compared to the ad libitum control (C), pair-fed control (PC) group or the zinc deficient + zinc (ZDZ) group. In addition, zinc deficiency resulted in significant reduction in growth of embryos (embryonic protein content, crown-rump length and number of somites) and in a significant retardation in development of organ primordia. Zinc supplementation of zinc deficient pregnant rats significantly improved crown-rump length, increased embryonic protein content and improved the development of somites. Moreover, the development of embryonic circulatory, nervous and musculoskeletal systems was improved by zinc supplementation of zinc deficient animals. CONCLUSION: These results show that zinc deficiency is embryopathic in vivo and that zinc supplementation of zinc deficient rats ameliorated the embryopathic effects of zinc deficiency.     

Effect of oral administration of different combinations of killed bacteria on some depressed macrophage functions in tumor-bearing rats

In the present study, we compared the ability of different bacterial species administered orally in various combinations to restore some depressed peritoneal macrophage functions in tumor-bearing rats. Phagocytosis, killing of Candida albicans and chemotactic response of resident peritoneal cells from treated tumor-bearing rats were influenced by different associations of bacteria. In particular, when Staphylococcus aureus was administered together with other bacterial species, the phagocytic activity of peritoneal cells was restored to normal values, and intracellular killing of C. albicans was enhanced. The results are discussed in relation to the possible influence of mucosal bacterial flora on the level of activation of peritoneal macrophages. The possibility that bacterial species can influence in various ways immunocompetent cells in relation to the different chemical composition of some common structures is also discussed.     

Vascular wall damage in rats induced by methidathion and ameliorating effect of vitamins E and C

We examined the effect of subacute methidathion (MD) administration on vascular wall damage and evaluated the ameliorating effects of combination of vitamins E and C against MD toxicity. The experimental groups were: rats treated with corn oil (control group), rats treated with 5 mg/kg MD (MD), and rats treated with 5 mg/kg body weight MD plus vitamin E and vitamin C (MD+Vit). The groups were given MD by gavage on 5 days a week for 4 weeks at a daily dose 5 mg/kg (MD and MD+Vit) using corn oil as the vehicle. Vitamins E and C were injected at doses of 50 mg/kg intramuscularly and 20 mg/kg intraperitoneally, respectively, after the treatment with MD in the MD+Vit group. The levels of malondialdehyde (MDA) were determined in the aortic tissue. Histopathological examination was examined in the thoracic aortic tissue. MDA levels were higher in the MD group than the control group and lower in the MD+Vit group than MD group. MD administration led to irregulation, prominent breaks, and fragmentation of the elastic fibers but decrease in the irregulation and fragmantation of the elastic fibers with the combination of vitamins E and C in MD-treated rats. In conclusion, it is likely that subacute MD administration caused vascular wall damage, and that treatment with a combination of vitamins E and C after the administration of MD can reduce vascular wall damage caused by MD.     

梭曼中毒大鼠脂质过氧化损伤及抗氧化剂的作用

目的 以大鼠血清乙酰胆碱酯酶(AChE)活力变化为梭曼(soman)中毒程度指标，研究维生素A和维生素E对急性中毒大鼠的血清、大脑和肝脏组织中超氧化物歧化酶(SOD)、一氧化氮合酶(NOS)和总抗氧化力(T—AoC)的影内，探讨抗氧化剂维生素A和维生素E对梭曼中毒大鼠AChE及脂质过氧化损伤的保护作用。方法 雄性大鼠40只，按体重随机分为阴性对照组、阳性对照组、维生素A组、维生素E组。阴性对照组和阳性对照组每日灌胃5ml/kg的菜籽油；维生素A组每日灌胃2ml/kg的维生素A；维生素E组每日灌胃2．5ml/kg的维生素E，共灌胃9d。第10日除阴性对照组外其余各组大鼠均皮下注射0．9LD50梭曼，2h后断头处死并取样。测定大鼠血清、大脑、肝脏的T—AOC、SOD和NOS及血清AChE活力。结果 梭曼中毒2h后，血清乙酰胆碱酷酶(AChE)及血清、大脑、肝脏组织中SOD活力和T—AoC水平下降，NOS活力提高；维生素A和维生素E均能提高SOD、T—AOC和AChE活力，而降低NOS活力。结论 经皮下注射0．9LD50梭曼可引起AChE活力显著下降，表明大鼠已严重中毒，中毒时伴有明显的脂质过氧化损伤。中毒前大鼠用维生素A和维生素E预处理，能够保护AChE活力，降低NOS活力，减少N0自由基的生成，同时，提高SOD、T—AoC水平。提示维生素A和维生素E对梭曼中毒有较好的预防作用。     

Tumor cytotoxicity of peritoneal macrophages induced by OK-432

In the present study we investigated the enhancement of cytotoxicity of peritoneal macrophages induced by OK-432. Rats received an i.p. injection of OK-432 at doses of 0.1, 0.5 or 1.0 KE/rat. Two days later, rats were sacrificed and peritoneal macrophages were isolated. Then the number of macrophages was counted, and the macrophages were analyzed for their lactic dehydrogenase (LDH) activity, acid phosphatase (ACP) activity, phagocytic activity, secretion of nitric oxide (NO) and cytotoxicity. The number of peritoneal macrophages, the activity of LDH and ACP, phagocytic activity, NO secretion, and cytotoxicity were increased with the increasing doses of OK-432. The results suggested that OK-432 enhanced tumor cytotoxicity of peritoneal macrophages by three steps. The first step is to attract a great number of macrophages into the peritoneal cavity. The second step is to enhance the phagocytic and eliminating function of these macrophages. The last step is to increase the non-contact cytotoxicity of macrophages.     

Sodium sulfite aggravated allergic sensitization and airway inflammation in mite allergen sensitized BALB/c mice

Sulfur dioxide is a typical air pollutant. Sulfite, which is formed at the bronchial mucosa from inhaled sulfur dioxide, might play a role in the exacerbation of asthma. In this study, we investigated the effects of sodium sulfite and its interaction with a house dust mite (Dermatophagoides pteronyssinus, Der p) on allergic sensitization and airway inflammation. BALB/c mice were divided into four groups: control (n = 10), mite intranasal (mIN, n = 12), sodium sulfite intranasal (sIN, n = 12) and mIN + sIN (n = 12). In non-control groups, the mice were sensitized on day 8 and day 15 with mite allergen subcutaneously. Mite allergen was then administrated intranasally from day 15 to day 22 in mIN and mIN+sIN groups. Sodium sulfite was administrated in sIN and mIN + sIN groups intranasally from day 1 to day 22. Plasma Der p-specific IgE, IgG2a, lung histopathology and cytokine levels (IL-5 and IFN-γ) were analyzed. In comparison between mIN (or sIN) and mIN + sIN group, Der p-specific IgE levels were significantly higher in mIN + sIN group (p < 0.01). Besides, Der p-specific IgG2a level was significantly lower in mIN + sIN group than mIN (or sIN) group (p < 0.01). The peribronchiolar, alveolar and total inflammatory scores were increased in the mIN + sIN group comparing with the control group (p < 0.05, p < 0.01, p < 0.01, respectively). Lung supernatant in mIN + sIN group has higher IL-5/IFN-γ ratio than control, mIN or sIN group (all p < 0.05). Our study concluded sodium sulfite may enhance allergic sensitization as well as airway inflammation in mite allergen sensitized BALB/c mice.     

The protective effect of sulfite on menadione- and diquat-induced cytotoxicity in isolated rat hepatocytes

Menadione and diquat cause toxicity in isolated hepatocytes. The toxicities of both menadione and diquat are primarily due to redox cycling and consequent oxidative stress. Menadione toxicity, however, has another component as the compound also possesses alkylating and oxidating properties allowing it to interact directly with cellular nucleophiles. Sulfite afforded considerable protection of isolated rat hepatocytes against the toxicity of menadione. This protective effect of sulfite may have several components. Sulfite effectively competed with glutathione (GSH) for conjugation with menadione, sparing intracellular GSH which may continue to detoxify reactive oxygen species formed through menadione redox cycling. The menadione sulfite conjugate undergoes much slower redox cycling than both menadione and the menadione glutathione conjugate. Sulfite also showed some degree of protection of hepatocytes from the toxicity of diquat. Diquat is a "pure" redox cycling agent and the protective effect of sulfite may involve the liberation of GSH from GSSG by sulfitolysis. This would again bolster intracellular GSH levels allowing further GSH-dependent detoxification of reactive oxygen species through cellular GSH peroxidases. In conclusion, our data illustrate the potential of inorganic sulfite to support the intracellular detoxification function of GSH, both against reactive electrophilic metabolites and against agents undergoing redox cycling.     

Effect of sulfite on red blood cell deformability ex vivo and in normal and sulfite oxidase-deficient rats in vivo

The effect of sulfite, a widely used food additive, on red blood cell deformability ex vivo and in vivo was investigated. Ex vivo experiments were conducted in human blood exposed to sulfite (5, 10 and 20 mM). In vivo experiments were carried out in sulfite oxidase-competent (SOXC) and sulfite oxidase-deficient (SOXD) rats. In the in vivo experiments, sulfite was administered in the form of sodium metabisulfite (Na₂S₂O₅, 25 mg/kg/day) via drinking water. Vitamin E dissolved in olive oil at a dose of 50 mg/kg was administered by gastric gavages. Red blood cell (RBC) deformability was determined at various fluid shear stresses using an ektacytometer. Ex vivo sulfite exposure to RBC did not affect RBC deformability. In the in vivo experiments, although RBC deformability was not affected by sulfite treatment in SOXD rats, it was found to be significantly increased in SOXC rats. Vitamin E treatment in combination with sulfite caused impairment in RBC deformability in both SOXC and SOXD rats. We suggest that sulfite needs to be oxidized in order to improve RBC deformability.     

Hepatoprotective and immunomodulatory properties of Tinospora cordifolia in CCl4 intoxicated mature albino rats

Effect of Tinospora cordifolia extract on modulation of hepatoprotective and immunostimulatory functions in carbon tetrachloride (CCl4) intoxicated mature rats is reported here. Administration of CCl4 (0.7 ml/kg body weight for 7 days) produces damage in the liver as evident by estimation of enzymes such as serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transminase (SGPT) and alkaline phosphatase (ALP) as well as serum bilirubin level. CCl4 administration also causes immunosuppressive effects as indicated by phagocytic capacity, chemotactic migration and cell adhesiveness of rat peritoneal macrophages. However, treatment with T. cordifolia extract (100 mg/kg body weight for 15 days) in CCl4 intoxicated rats was found to protect the liver, as indicated by enzyme level in serum. A significant reduction in serum levels of SGOT, SGPT, ALP, bilirubin were observed following T. cordifolia treatment during CCl4 intoxication. Treatment with T. cordifolia extract also deleted the immunosuppressive effect of CCl4, since a significant increment in the functional capacities of rat peritoneal macrophages (PM phi) was observed following T. cordifolia treatment. The results of our experiment suggest that treatment by T. cordifolia extract may be the critical remedy for the adverse effect of CCl4 in liver function as well as immune functions.