Acute exposure to solar simulated ultraviolet radiation affects oxidative stress-related biomarkers in skin, liver and blood of hairless mice

The ultraviolet (UV) region of solar radiation is a critical factor in the initiation and development of a number of skin diseases. However, it is not only skin which is directly exposed to solar light that is affected by UV radiation, through low molecular weight mediators, generated upon irradiation, "non-skin" tissues can also be affected. The aim of this study was to examine in detail, the acute effects of UVA and UVB wavebands on hairless mice. Female SKH-1 hairless mice were exposed to a single dose of UVB (200, 800 mJ/cm(2)) or UVA (10, 20 J/cm(2)) using a solar simulator. The effects on haematological parameters, activity and/or expression of antioxidant enzymes, level of glutathione (GSH), markers of oxidative damage (lipid peroxidation and carbonylated proteins) were analysed in erythrocytes, plasma, liver and whole skin homogenates. No macroscopic changes were observed either 4 or 24 h after UVA/UVB exposure. The blood count showed a significant increase in leukocyte number and reduction of platelets 4 h following UVA and UVB irradiation, which disappeared 24 h after irradiation except for the higher UVA dose. Changes in oxidative stress-related parameters, particularly activity of catalase (CAT) and superoxide dismutase (SOD) and level of GSH and lipid peroxidation products, were found in skin, erythrocytes and liver. The expression of several enzymes (CAT, SOD, glutathione transferase (GST), nicotinamide adenine dinucleotide (phosphate) quinone oxidoreductase (NQO1) and hem oxygenase-1 (HO-1)) in skin was affected following UVA and UVB radiation. Increase in carbonylated proteins was found in plasma and skin samples.     

补肾活血汤对制动应激所致卵巢功能减退大鼠的影响

目的:探讨补肾活血汤对制动应激大鼠卵巢功能的保护作用。方法:采用重复制动应激法造成大鼠卵巢功能早期减退模型,造模同时灌胃给予补肾活血汤,以放免法检测大鼠血清中性激素水平,酶免法检测血清中激活素和抑制素水平,观察补肾活血汤对造模大鼠卵巢功能的影响。结果:补肾活血汤对制动应激所致卵巢功能早期减退大鼠有明显的保护作用,其高、中剂量可明显升高模型大鼠血清雌二醇水平(P<0.05),降低模型大鼠血清中异常升高的激活素水平(P<0.05),升高抑制素和卵泡抑素水平(P<0.05~0.01)。结论:补肾活血汤对制动应激所致卵巢功能早期减退大鼠的卵巢功能有明显的保护作用。     

Glutathione depletion, lipid peroxidation and mitochondrial dysfunction are induced by chronic stress in rat brain.

Damage to the mitochondrial electron transport chain has been suggested to be an important factor in the pathogenesis of a range of neurodegenerative disorders. We have previously demonstrated that chronic stress induced an increase in nitric oxide (NO) production via an expression of inducible NO synthase (iNOS) in brain. Since it has been demonstrated that NO regulates mitochondrial function, we sought to study the susceptibility of the mitochondrial respiratory chain complexes to chronic restrain stress exposure in brain cortex. In adult male rats, stress (immobilization for six hours during 21 days) inhibits the activities of the first complexes of the mitochondrial respiratory chain (inhibition of 69% in complex I-III and of 67% in complex II-III), without affecting complex IV activity, ATP production and oxygen consumption. The mitochondrial marker citrate synthase is not significantly affected by stress after 21 days, indicating that at this time the mitochondrial structure is still intact. Moreover, the administration of the preferred inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine (400 mg/kg i.p. daily from days 7 to 21 of stress) protects against the inhibition of the activity of complexes of the mitochondrial respiratory chain as well as prevents NO(x)(-) accumulation, lipid peroxidation and glutathione depletion induced by stress. These results suggest that a sustained overproduction of NO via iNOS is responsible, at least in part, of the inhibition of mitochondrial respiratory chain caused by stress and that this pathway also accounts for the oxidative stress found in this situation.     

罗汉果皂苷提取物对糖尿病小鼠血糖、血脂及抗氧化作用的影响

目的探讨罗汉果皂苷提取物对四氧嘧啶糖尿病小鼠血糖的调节作用及其作用机制。方法分别以50,100,300,500 mg.kg-1bw剂量的罗汉果皂苷提取物连续30 d灌胃四氧嘧啶糖尿病小鼠,末次给药后眼眶取血测定血糖、血脂指标;分离肝组织测定抗氧化指标。结果①100,300和500 mg.kg-1bw剂量组可降低四氧嘧啶糖尿病小鼠的血糖(P<0.01),且以中剂量100 mg.kg-1bw的降糖作用最佳。②罗汉果皂苷提取物可降低四氧嘧啶糖尿病小鼠的TC、TG含量,提高HDL-C含量,有利于糖尿病小鼠血脂水平的恢复(P<0.01或P<0.05)。③罗汉果皂苷提取物可降低四氧嘧啶糖尿病小鼠肝脏的MDA含量,提高SOD、GSH-Px含量,表明罗汉果皂苷提取物可改善糖尿病小鼠的氧化应激水平(P<0.01或P<0.05)。④在其最佳剂量(100 mg.kg-1bw),罗汉果皂苷提取物的降血糖,降血脂及其抗氧化效果同消渴丸相当(P>0.01)。结论罗汉果皂苷提取物对糖尿病小鼠有明显的治疗作用,其降糖机制可能与提高糖尿病小鼠抗氧化能力及改善血脂水平有关。     

Effect of astaxanthin on kidney function impairment and oxidative stress induced by mercuric chloride in rats.

Reactive oxygen species are implicated as mediators of tissue damage in the acute renal failure induced by inorganic mercury. Astaxanthin (ASX), a carotenoid with potent antioxidant properties, exists naturally in various plants, algae, and seafoods. This paper evaluated the ability of ASX to prevent HgCl(2) nephrotoxicity. Rats were injected with HgCl(2) (0 or 5 mg/kg b.w., sc) 6h after ASX had been administered (0, 10, 25, or 50mg/kg, by gavage) and were killed 12h after HgCl(2) exposure. Although ASX prevented the increase of lipid and protein oxidation and attenuated histopathological changes caused by HgCl(2) in kidney, it did not prevent creatinine increase in plasma and delta-aminolevulinic acid dehydratase inhibition induced by HgCl(2). Glutathione peroxidase and catalase activities were enhanced, while superoxide dismutase activity was depressed in HgCl(2)-treated rats when compared to control and these effects were prevented by ASX. Our results indicate that ASX could have a beneficial role against HgCl(2) toxicity by preventing lipid and protein oxidation, changes in the activity of antioxidant enzymes and histopathological changes.     

Oxidative stress associated hepatic and renal toxicity induced by ricin in mice.

Ricin a glycoprotein from the Ricinus communis seeds, is known to have diverse toxic effects on cells of different visceral organs. We have studied the hepatotoxicity, nephrotoxicity, and oxidative stress following i.p. administration of ricin (25 microg/kg) in Swiss albino male mice. The results of this study revealed that activities of various enzymes like glutamic pyruvic transaminase (GPT), alkaline phosphatase (ALP), gamma glutamyl transpeptidase (gamma-GT), and lactate dehydrogenase (LDH) were increased in plasma, liver, and kidney tissues indicating damage in liver and kidney. Blood urea level was also increased. However, blood creatinine and bilirubin were not altered. Lipid peroxidation increased to 49 and 25% in hepatic and renal tissue. Total non-protein sulfhydryl content decreased in plasma (12%), hepatic (29%), and renal (16%) tissues. Superoxide dismutase activity decreased significantly in liver (43%) and kidney (37%). The activity of glutatione peroxidase was also decreased. The decrease was more prominent in kidney than liver. A significant increase, 20 to 27% in the activity of catalase was observed in plasma, liver, and kidney. These results indicate that ricin produces hepatoxicity, nephrotoxicity, and oxidative damage at 24 h of post treatment. The hepatotoxicity was more prominent than nephrotoxicity.     

Naringin alleviates cognitive impairment,mitochondrial dysfunction and oxidative stress induced by d-galactose in mice

Role of mitochondrial dysfunction and oxidative stress has been well documented in aging and related disorders such as Alzheimer’s disease. Bioflavonoids have been reported to have a therapeutic potential against several age related processes. Bioflavonoids are being used as a neuroprotectants in the treatment of various neurological disorders including aging. Therefore, present study has been conducted in order to explore the possible role of naringin against d-galactose induced cognitive dysfunction, oxidative damage and mitochondrial dysfunction in mice. Chronic administration of d-galactose (100 mg/kg) for 6 weeks significantly impaired cognitive performance (both in Morris water maze and elevated plus maze), locomotor activity, oxidative defense and mitochondrial complex (I, II and III) enzymes activities as compared to sham group. Six weeks naringin (40 and 80 mg/kg) treatment significantly improved cognitive performance, oxidative defense and restored mitochondria complex enzyme activities as compared to control (d-galactose). Naringin treatment significantly attenuated acetylcholine esterase activity in d-galactose treated mice. In conclusion, present study highlights the potential role of naringin against d-galactose induced cognitive impairment, biochemical and mitochondrial dysfunction in mice.     

扇贝多肽对长期紫外线A辐射无毛小鼠皮肤所致突变型p53,EGFR和SP表达的抑制作用

探讨局部应用扇贝多肽(PCF)对长期长波紫外线(UVA)辐射无毛小鼠皮肤所致突变型p53,表皮生长因子受体(EGFR)和P物质(SP)表达的影响。建立长期长波紫外线辐射无毛小鼠皮肤模型,免疫组化法测定皮肤组织突变型p53,表皮生长因子受体和P物质的表达。无毛小鼠背部皮肤每天一次应用5％和20％扇贝多肽可显著降低长期长波紫外线辐射(剂量为4556.4 J·cm-2)所致突变型p53,表皮生长因子受体和P物质的过表达。和模型组相比,5％扇贝多肽可分别降低突变型p53,表皮生长因子受体和P物质的表达至86.7％,81.7％和85.2％。20％扇贝多肽几乎可完全对抗长期长波紫外线辐射所致的过表达。扇贝多肽可通过抑制无毛小鼠皮肤中突变型p53,表皮生长因子受体和P物质的过表达,从而可保护皮肤防止光致癌和光老化。     

Role of alpha2C-adrenoceptors in the reduction of skin blood flow induced by local cooling in mice

BACKGROUND AND PURPOSE: The reduction of skin blood flow induced by local cooling results from a reflex increase in sympathetic output and an enhanced vasoconstrictor activity of cutaneous vessels. The present study investigated the latter local response in vivo in tetrodotoxin-treated mice, in which the sympathetic nerve tone was abolished. EXPERIMENTAL APPROACH: Male ddY mice, anaesthetized with pentobarbitone, were treated with tetrodotoxin and artificially ventilated. The plantar skin blood flow (PSBF) was measured by laser Doppler flowmetry. KEY RESULTS: Cooling the air temperature around the left foot from 25 to 10 degrees C decreased the PSBF of the left foot. Bunazosin, an alpha (1)-adrenoceptor antagonist, RS79948, an alpha (2)-adrenoceptor antagonist, and MK-912, an alpha (2C)-adrenoceptor antagonist, all significantly inhibited the cooling-induced reduction of PSBF; the inhibition by bunazosin was relatively small compared with that by RS79948 and MK-912. The response was not affected by guanethidine or bretylium, but was diminished in adrenalectomized mice. An intra-arterial injection of clonidine, an alpha (2)-adrenoceptor agonist, to the left iliac artery of adrenalectomized mice caused a transient decrease in PSBF, which was significantly augmented at 10 degrees C. MK-912 suppressed only the augmented portion at 10 degrees C. Y-27632, H-1152 and fasudil, Rho kinase inhibitors, also inhibited the cooling-induced reduction of PSBF. RS79948 caused no further reduction of the cooling-induced response after the inhibition by Y-27632. CONCLUSIONS AND IMPLICATIONS: Local cooling-induced reduction of skin blood flow in mice primarily results from increased reactivity of alpha (2C)-adrenoceptors to circulating catecholamines, in which the Rho/Rho kinase pathway is involved.     

Effect of carvedilol on behavioral, mitochondrial dysfunction, and oxidative damage against d-galactose induced senescence in mice

Growing evidence indicates that oxidative stress and mitochondrial dysfunction plays a critical role in brain aging. Chronic injection of d-galactose can cause gradual deterioration in learning and memory capacity and serve as an animal model of aging. Recently, potential therapeutic effect of carvedilol (CAR) has been reported by virtue of which its antioxidant and mitochondrial permeability transitional property. The present study has been designed to explore the CAR effect against d-galactose-induced behavioral, biochemical, and mitochondrial dysfunction in mice. Systemic administration of d-galactose for 6 weeks significantly impaired behavioral (learning and memory and locomotor activity), biochemical parameters (raised lipid peroxidation, nitrite concentration, depletion of reduced glutathione, and catalase activity), and mitochondrial enzymes (decreased complex I, II and III enzymes levels) as compared to sham group. CAR (2.5 and 5 mg/kg) treatment significantly improved behavioral abnormalities and biochemical and cellular alterations as compared to control. Chronic administration of d-galactose for a period of 6 week results into a significant increase of acetylcholine esterase enzyme level. CAR (2.5 and 5 mg/kg) treatment significantly attenuated the elevated level of acetylcholine esterase of mice. In conclusion, present studies highlight the protective effects of CAR against d-galactose-induced behavioral, biochemical, and mitochondrial dysfunction in mice. The study further provides a hope that CAR could be used in the management of cognitive dysfunction and related symptoms during aging.     

New antitumor substances, BE-12406A and BE-12406B, produced by a streptomycete. I. Taxonomy, fermentation, isolation, physico-chemical and biological properties

New antitumor substances, designated BE-12406A and BE-12406B, were isolated from the culture broth of a streptomycete, strain BA 12406. The active principles were extracted from mycelium by methanol and successively purified by silica gel column chromatography and preparative TLC. BE-12406A and BE-12406B inhibited the growth of vincristine-resistant or doxorubicin-resistant P388 murine leukemia cell lines as well as their parent sensitive cell line. In in vivo experiments, BE-12406A inhibited the growth of S-180 murine ascites tumor.     

Effect of L-arginine on restraint stress induced modulation of immune responses in rats and mice.

The present study investigates the role of nitric oxide (NO) on restraint stress (RS)-induced modulation of humoral and cell-mediated immune responses in rats and mice. RS produced suppression of humoral immune response, i.e., anti-SRBC antibody titre ( 7.38 +/- 0.32 versus 4.13 +/- 0.30; mean +/- S.E.M., P < 0.001). In case of cell-mediated immunity, in delayed type hypersensitivity (DTH) response the change in paw volume decreased from 0.069 +/- 0.003 mm (mean +/- S.E.M.) in control non-stressed group to 0.038 +/- 0.002 mm in the stressed group (P < 0.001) while percentage leucocyte migration inhibition (% LMI) decreased from 39.7 +/- 1.95 in control non-stressed animals to 15.2 +/- 1.07 in animals subjected to stress (P < 0.01). Pretreating the animals with an NO precursor, L-arginine (1000 mg kg-1, i.p.) antagonized the effect of RS on humoral (anti-SRBC antibody titre 6.50 +/- 0.27 versus 4.13 +/- 0.30, P < 0.001 ) and cell-mediated (DTH response 0.066 +/- 0.002 mm versus 0.038 +/- 0.002 mm, P < 0.001; % LMI 41.5 +/- 1.46 versus 15.2 +/- 1.07, P < 0.01) immune responses. Administration of 7-nitroindazole (7-NI, 50 mg kg-1, i.p.), an inhibitor of neuronal NO synthase, alone further enhanced the immunosuppressive effect of RS (anti-SRBC antibody titre 2.75 +/- 0.25 versus 4.13 +/- 0.30, P < 0.001; DTH response 0.019 +/- 0.002 mm versus 0.038 +/- 0.002 mm, P < 0.001; % LMI 5.0 +/- 1.08 versus 15.2 +/- 1.07, P < 0.01). However, when given before L-arginine treatment, 7-NI reversed the effect of the latter drug on stress-induced immunomodulation (anti-SRBC antibody titre 3.00 +/- 0.27 versus 6.5 +/- 0.27, P < 0.001; DTH response 0.043 +/- 0.003 mm versus 0.066 +/- 0.002 mm, P < 0.001; % LMI 12.0 +/- 0.93 versus 41.5 +/- 1.46, P < 0.01). Unlike its effect on RS-induced immune responsiveness, L-arginine (250, 500, 1000 mg kg-1) when given for 5-7 days to naive non-stressed animals produced dose dependent suppression of both humoral (anti-SRBC antibody titre 6.4 +/- 0.32 versus 5.4 +/- 0.32, 4.0 +/- 0.27, 3.1 +/- 0.30, respectively) and cell-mediated (DTH 0.065 +/- 0.003 mm versus 0.064 +/- 0.004 mm, 0.039 +/- 0.003 mm, 0.020 +/- 0.002 mm, respectively and % LMI 37.52 +/- 1.58 versus 30.48 +/- 1.07, 28.18 +/- 1.22, 19.76 +/- 0.83, respectively) immune responses. 7-NI significantly blocked these immunosuppressive effects of L-arginine (anti-SRBC antibody titre 6.0 +/- 0.38 versus 3.1 +/- 0.030, P < 0.01; DTH response 0.056 +/- 0.004 mm versus 0.020 +/- 0.002 mm, P < 0.001; % LMI 34.76 +/- 1.31 versus 19.76 +/- 0.83, P < 0.01). However, 7-NI when given to non-stressed animals failed to modulate immune responsiveness. Thus, NO appears to play an important role in RS-induced immunomodulation and these effects are different from its effect on immune responsiveness in non-stressed animals.     

原花青素对 Aβ25-35诱导的小鼠学习记忆损伤的影响

目的：观察原花青素对淀粉样β蛋白25‐35（Aβ25‐35）诱导的小鼠学习记忆损伤的影响。方法将30只雄性2月龄C57bl／6小鼠随机均分为五组：E组为空白对照;其余四组采用双侧侧脑室注射Aβ25‐35制备的小鼠学习记忆损伤模型后,D组为模型对照,A、B和C组分别用原花青素50、100和150 mg／kg灌胃,连续30 d。D组和E组采用灭菌双蒸水灌胃。采用Y迷宫测试小鼠短期学习记忆能力;HE染色观察小鼠海马CA1区神经元损伤情况;化学比色法测定小鼠血清中丙二醛（MDA）、羟自由基（OH －）、谷胱甘肽（GSH）、总抗氧化能力（T‐AOC）和超氧化物歧化酶（SOD）表达水平;Western blot测定硝基络氨酸（NTS）、过氧化物还原酶1（Prdx‐1）在小鼠海马组织中的表达。结果与D组比较,A、B和C组小鼠短期学习记忆能力较好,CA1区深染神经细胞比例呈剂量依赖性下降,血清GSH、T‐AOC和SOD含量增高,且海马组织中NTS表达水平降低,Prdx‐1表达水平升高（ P＜0．01或P＜0．05）。结论原花青素能改善Aβ25‐35诱导的小鼠氧化应激水平,从而减轻小鼠海马神经退行性病变和小鼠学习记忆损伤。     

前列地尔联合丁苯酞对LI合并轻度VCI的疗效及其对患者脑血流灌注、氧化应激和认知功能的影响

目的探讨前列地尔注射液联合丁苯酞治疗腔隙性脑梗死(LI)合并轻度血管性认知功能障碍(VCI)的效果及其对患者脑血流灌注、氧化应激和认知功能的影响。方法将382例LI合并轻度VCI患者随机分为对照组和观察组,每组191例,对照组给予丁苯酞注射治疗,观察组基于以上治疗给予前列地尔注射治疗,观察治疗前及治疗1个月后的脑血流灌注情况、氧化应激水平、神经功能损伤标志物水平、认知功能和日常生活活动能力变化。结果治疗1个月后,两组大脑前动脉(ACA)和大脑中动脉(MCA)的平均血流速度提高(P<0.05),两组血清一氧化氮(NO)、内皮素(ET)、丙二醛(MDA)水平降低(P<0.05),超氧化物歧化酶(SOD)水平升高(P<0.05),两组血浆同型半胱氨酸(Hcy)、胱抑素C(CysC)、神经元特异性烯醇化酶(NSE)及脑活性肽100-β(S-100β)水平降低(P<0.05),两组简易精神状态检查测量表(MMSE)评分、蒙特利尔量表(MoCA)评分及日常生活能力量表(ADL)评分升高(P<0.05),上述指标两组比较差异均有统计学意义(P<0.05)。结论前列地尔注射液联合丁苯酞治疗LI合并轻度VCI患者疗效确切,能明显改善脑血流灌注,减轻氧化应激损伤并修复脑组织神经缺损,利于患者认知功能和日常生活活动能力的提高。     

Epiderstatin, a new inhibitor of the mitogenic activity induced by epidermal growth factor. I. Taxonomy, fermentation, isolation and characterization

Inhibitors of mitogenic activity induced by epidermal growth factor (EGF) were screened from culture broths of soil microorganisms. A strain of actinomycetes has been found to produce a new glutarimide antibiotic named epiderstatin which inhibits the incorporation of [3H]thymidine into quiescent animal cells stimulated by EGF. Taxonomic studies have revealed that the producing strain belongs to a subspecies of Streptomyces pulveraceus, thus the name, Streptomyces pulveraceus subsp. epiderstagenes was given to this strain. The molecular formula (C15H20N2O4) and UV profile (lambda max 295 nm) of the antibiotic are distinct from other known antibiotics. It inhibited the incorporation of [3H]thymidine into quiescent cells stronger than into growing cells.     

Effect of alcohol intake on some disturbances induced by chronic exposure to carbon disulphide in rats. I. Behavioural alterations

Female white Wistar rats were exposed to CS2 vapour (0.8 mg CS2/1 air) 11 months and to 10% ethanol as the only drinking liquid for the last 3 months of exposure. Spontaneous exploratory motor activity (SEMA), open-field behaviour, passive avoidance performance and the avoidance acquisition were tested. Ethanol did not change the exploratory motor activity and behaviour of CS2-exposed rats in the open-field and passive avoidance tests but it affected their performance in the conditioned avoidance test. The analysis of data suggests that ethanol may adversely affect memory and learning ability in CS2-exposed rats.     

Neurotoxicological mechanism of methylmercury induced by low-dose and long-term exposure in mice: oxidative stress and down-regulated Na+/K(+)-ATPase involved

Methylmercury (MeHg), a potent neurotoxicant, easily passes through the blood-brain barrier (BBB), accumulates in the brain regions and causes severe irreversible damage. However, the neurotoxic effects and action mechanisms of MeHg are still unclear, especially in low-dose and long-term exposure. In this study, we attempted to explore the toxic effects of low-dose MeHg (0.05 mg/kg/day), which was the possible exposed dose by ingestion in MeHg-contaminated areas, on the time course of changes in locomotor activities and auditory brainstem response (ABR) system after administration for 7 consecutive weeks in mice. The results showed that the retention time on the rotating rod (60 rpm) was preferentially decreased after 1-week oral administration with MeHg. The locomotor activities parameters of ambulatory distances and stereotype-1 episodes were significantly increased and vertical-plane entries were progressively decreased after MeHg exposure in 3 consecutive weeks. Gradually progressive abnormality of ABR (increase in hearing thresholds, prolonged absolute and interwave latencies) was found during 4-6 weeks administration of MeHg. These impairments correlated with significant Hg accumulation and biochemical alterations in brain regions and/or other tissues, including the increase of lipid peroxidation (LPO) production, influence of Na+/K(+)-ATPase activities and nitric oxide (NO) levels were found. These findings provide evidence that the signaling of oxidative stress/Na+/K(+)-ATPase/NO plays a role in the underlying mechanisms of the neurotoxic effects induced by low-dose and long-term exposure of MeHg.     

TiO2 nanoparticle‐induced neurotoxicity may be involved in dysfunction of glutamate metabolism and its receptor expression in mice

Titanium dioxide nanoparticles (TiO₂ NPs) have been used in environmental management, food, medicine, and industry. But TiO₂ NPs have been demonstrated to cross the blood–brain barrier and store up in the brain organization, leading to glutamate‐mediated neurotoxicity. However, the neurotoxicity in the brain is not well understood. In this study, mice were exposed to 1.25, 2.5, or 5 mg/kg body weight TiO₂ NPs for 9 months, and the glutamate–glutamine cyclic pathway and expressions of glutamate receptors associated with the hippocampal neurotoxicity were investigated. Our findings showed elevations of glutamate release and phosphate‐activated glutaminase activity, and reductions in glutamine and glutamine synthetase in the hippocampus following exposure to TiO₂ NPs. Furthermore, TiO₂ NPs significantly inhibited the expression of N‐methyl‐d ‐aspartate receptor subunits (including NR1, NR2A, and NR2B) and metabotropic glutamate receptor 2 in mouse hippocampus. These findings suggest that the imbalance of glutamate metabolism triggered inhibitions of glutamate receptor expression in the TiO₂ NP‐exposed hippocampus. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 655–662, 2016.     

Effect of trehalose on manganese‐induced mitochondrial dysfunction and neuronal cell damage in mice

Chronic overexposure to manganese (Mn) has been verified to induce mitochondrial dysfunction, which is related to oxidative damage. The autophagic‐lysosomal degradation pathway plays a vital role in the removal of impaired mitochondria through a specific quality control mechanism termed mitophagy. However, trehalose functions as an inducer of autophagy by an mTOR‐independent mechanism, and little data report its effect on Mn‐induced mitochondrial dysfunction. To explore the possibility that trehalose could be effective in interfering with the Mn‐induced mitochondrial dysfunction, we used trehalose (2% and 4% (g/vol (mL))) in a mouse model of manganism. Our data showed that mice developed weary motor and behavioural deficits after exposure to Mn for 6 weeks. Overexposure to Mn resulted in mitochondrial dysfunction and neuronal cell damage in the basal nuclei of mice, which could be ameliorated by trehalose pre‐treatment. Moreover, our results indicated that trehalose pre‐treatment significantly reduced the oxidative damage and enhanced the activation of mitophagy. The findings clearly demonstrated that trehalose could relieve Mn‐induced mitochondrial and neuronal cell damage through its antioxidative and mitophagy‐inducing effects.