UVA对花背蟾蜍微核及核异常的诱导

为了研究紫外线A对花背蟾蜍的毒性作用,选择微核及核异常为毒理监测指标,对花背蟾蜍红细胞进行观察.结果表明,紫外线A对花背蟾蜍成熟红细胞和非成熟红细胞核异常均有诱导作用并随照射强度的增加而不断增加.在150 min的紫外线A短时间照射内,紫外线对核异常能够产生一定的抑制作用.同时在一定范围内紫外线A能够刺激造血器官释放新的红细胞至外周血中以补充损伤的成熟红细胞.紫外线诱导的核异形主要是核畸形和核膨大.     

长波紫外线辐射对脊椎动物的影响

臭氧层空洞的加剧使紫外辐射不断加强,造成的环境污染已经成为广为关注的问题,但大多数都集中在中波紫外线(UVB)的生物学作用及其与两栖动物衰减关系的研究,有关长波紫外线(UVA)对生物体损伤作用的研究却甚少。本文综述了近年来UVA对脊椎动物损伤的研究概况,从细胞结构、酶活性、遗传物质、膜结构以及免疫系统等方面阐述了UVA的损伤机理,并对低剂量辐射诱导兴奋效应对紫外损伤的保护作用进行了简要概述。最后分析和总结了关于UVA损伤研究所存在的问题及两栖动物作为实验用动物模型在研究紫外线损伤中的作用。     

花背蟾蜍与环境监测

目的分析花背蟾蜍(Bufo Raddei)的分布、生活习性和繁殖行为,并对其进行环境污染物的检测研究进行总结。方法对花背蟾蜍的相关研究文章进行收集,并结合实地调查和观察的数据进行统计分析。结果花背蟾蜍及其蝌蚪在外周血红细胞微核及核异常、血清和肝脏抗氧化酶及脂质过氧化产物MDA、精子结构和活性、蝌蚪生长发育和肾脏结构等方面均表现出对环境污染物的极敏感性。结论花背蟾蜍可作为我国北方环境检测的首选两栖类物种。     

UVB照射后小鼠脾淋巴细胞DNA损伤程度的检测

用强度为30 μW/cm2、60 μW/cm2、90 μW/cm2、120 μW/cm2、150 μW/cm2的中波红斑效应紫外线(UVB)分别照射小鼠脾淋巴细胞5 min、15 min、30 min,采用单细胞凝胶电泳法(SCGE)检测UVB照射对细胞DNA的损伤,结果照射5 min和15 min时,DNA损伤程度与照射强度呈正相关;而照射30 min时,30 μW/cm2组DNA损伤程度最高,60 μW/cm2、90 μW/cm2、120 μW/cm2组损伤程度有所降低,而150 μW/cm2组又出现了高DNA损伤.认为通过SCGE来检测UVB照射对小鼠脾淋巴细胞的损伤程度,可广泛应用于环境毒理学中对DNA具有损伤作用的分析,为环境生物学研究辐射对生物体的影响提供借鉴.     

UVA照射通过诱导HO-1的表达对细胞产生保护作用

长波紫外线A(UVA,320～400nm)照射皮肤后可产生活性氧族(reactive oxygen species,ROS),导致细胞损伤或免疫抑制,还能增强UVB的损伤作用。但也有研究表明,UVA照射不会产生免疫抑制,它可通过诱导血红素氧合酶1(HO-1)的表达减轻UVB照射引起的免疫抑制效应,从而对细胞产生保护作用。由于UVA照射引起的损伤或保护作用尚存在很大争议,本文主要结合近年来的相关研究,概括了适量UVA照射引起的免疫改变以及相关研究,总结了UVA照射诱导HO-1表达所发挥的细胞保护作用,尤其是HO-1的抗氧化和免疫保护作用,这将为深入了解UVA照射的反应机制和新型防晒剂的应用提供一定的指导意义。     

辐射所致小鼠肾脏氧化损伤及川芎嗪的保护作用

目的:研究川芎嗪对辐射所致小鼠肾脏氧化损伤的预防和治疗作用。方法:采用60Co-γ射线5 Gy全身单次照射小鼠造模,在照射前和照射后分别于每天腹腔注射川芎嗪130 mg/kg,连续给药10 d,进行预防和治疗,并设对照组,观察肾组织中丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、还原型谷胱甘肽(GSH)、谷胱甘肽过氧化物酶(GSH-Px)及总抗氧化力(T-AOC)的变化。结果:与阴性对照组比较,照射可显著增加肾组织中MDA的含量(P<0.05),降低SOD、CAT的活性(P<0.05),升高GSH-Px活性(P<0.05),降低GSH含量(P<0.05),使肾组织T-AOC下降(P<0.05),。与照射组比较,给予川芎嗪预防和治疗后,均可降低肾组织MDA含量(P<0.05),升高肾组织T-AOC(P<0.05),且治疗组优于预防组,与阴性对照组无显著性差异。同时,预防组可使SOD活性和GSH含量升高(P<0.05),治疗组可使SOD和CAT活性增高(P<0.05),但均对GSH-Px活性无显著影响(P>0.05)。结论:川芎嗪具有很好的抗氧化作用,无论预防和治疗均可降低辐射所致小鼠肾脏的氧化应激损伤,并且治疗效果优于预防效果。     

紫外辐射对铜绿微囊藻中类菌孢素氨基酸(MAAs)的诱导效应

用8 w紫外灯,距离藻10 cm,以5 min/d、10 min/d、20 min/d连续照射6 d的间断处理和连续照射1 h、1.5 h、2 h、3h、6 h、12 h的连续处理两种方式处理铜绿微囊藻,测得水溶性色素提取液在200~400 nm间的吸收光谱与对照组相比较,没有产生新的吸收峰,说明MAAs的产生不需要紫外线的诱导。同时随着紫外辐射剂量的增加,MAAs的含量先增加,当达到一定的辐射剂量之后,MAAs的含量随着紫外辐射剂量的增加而减小。     

UVA诱发的1O2和O2-·产生与脂质过氧化水平关系的研究

紫外A(UVA,320 nm-400 nm)诱发的脂质过氧化反应是通过活性氧(ROS)介导的。在UVA照射之后,单线态氧(1O2)和超氧阴离子(O2-.)是细胞内最初产生的ROS,它们进一步生成过氧化氢(H2O2),羟自由基(.OH)等其它自由基。为了探讨UVA照射后最早生成的1O2和O2-.与细胞氧化损伤后果的关系,我们采用一种特异性检测1O2和O2-.的高灵敏度化学发光探针MCLA(2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimid-azo[1,2-α]pyrazin-3-one hydrochloride)检测人外周血淋巴细胞经UVA照射后的化学发光变化。发现不同剂量UVA照射后,细胞MCLA化学发光变化和MDA浓度变化一致。结果表明UVA照射后1O2和O2-.的水平与由此引发的脂质过氧化损伤存在正相关关系。因此,MCLA化学发光方法可望作为一种检测UVA诱发脂质过氧化水平的简单快速方法。     

肾缺血再灌注损伤大鼠肾内AQP2表达水平降低

目的了解肾脏缺血再灌注损伤(ischemia reperfusion injury, IRI)时肾内水通道蛋白-2(aquaporin 2, AQP2)免疫组织化学表达特点。方法建立大鼠右侧肾IRI 45min模型,随机分为缺血再灌注1d、3d、5d、7d组和假手术1d组,检测尿常规、尿比重、尿素氮、血肌酐;HE染色观察肾脏病理形态学变化;免疫组织化学染色观察IRI时肾脏AQP2表达的变化。结果 IRI后,大鼠出现尿量增多,尿比重降低,血肌酐、尿素氮均增加;HE染色示右侧肾充血,水肿以及肾小管上皮细胞肿胀、坏死和脱落;免疫组织化学染色显示AQP2免疫反应性在右肾降低,左肾增强。肾组织的变化在第7d基本恢复正常。结论肾IRI时肾内AQP2表达降低,可能与IRI后尿量增多、尿比重降低相关。     

西藏蟾蜍皮肤的组织学观察

为了解西藏蟾蜍Bufo tibetanus与其高海拔生活环境的适应性,采用常规石蜡切片和苏木精-伊红染色方法,对西藏蟾蜍雌雄性头部、躯干和四肢的背、腹侧皮肤显微结构进行了观察、测量和比较。结果显示皮肤的基本结构与已报道的无尾两栖类相似,由表皮和真皮组成。表皮较薄,由5~8层细胞构成,由外到内分为角质层、中间层和基底层。真皮较厚,分为疏松层和致密层。各部位大多表现为背侧皮肤厚度大于腹侧,相应部位大多为雌性大于雄性。皮肤厚度的变化在一定程度上与西藏蟾蜍运动方式和繁殖期间抱对行为相适应。皮肤腺体分粘液腺和颗粒腺2种。色素细胞主要分布在疏松层近表皮处,但在表皮和腺体周围也可见色素细胞的不连续分布。皮肤中毛细血管极其丰富,不仅在表皮下几乎成连续分布,而且在腺体周围也有密集分布。西藏蟾蜍皮肤结构明显表现出与生活环境中强紫外辐射和缺氧环境相适应的特点。     

Influence of the dark/light rhythm on the effects of UV radiation in the eyestalk of the crab Neohelice granulata

Crustaceans are interesting models to study the effects of ultraviolet (UV) radiation, and many species may be used as biomarkers for aquatic contamination of UV radiation reaching the surface of the Earth. Here, we investigated cell damage in the visual system of crabs Neohelice granulata that were acclimated to either 12L:12D, constant light, or constant dark, and were exposed to UVA or UVB at 12:00 h (noon). The production of reactive oxygen species (ROS), antioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation (LPO) damage, catalase activity, and pigment dispersion in the eye were evaluated. No significant differences from the three groups of controls (animals acclimated to 12L:12D, or in constant light, or not exposed to UV radiation) were observed in animals acclimated to 12L:12D, however, crabs acclimated to constant light and exposed to UV radiation for 30 min showed a significant increase in ROS concentration, catalase activity, and LPO damage, but a decrease in ACAP compared with the controls. Crabs acclimated to constant darkness and exposed to UV for 30 min showed a significantly increased ROS concentration and LPO damage, but the ACAP and catalase activity did not differ from the controls (animals kept in the dark while the experimental group was being exposed to UV radiation). Pigment dispersion in the pigment cells of eyes of animals acclimated to constant light was also observed. The results indicate that UVA and UVB alter specific oxidative parameters; however, the cell damage is more evident in animals deviated from the normal dark/light rhythm.     

Effects of ultraviolet radiation on human cutaneous nerve fibres

Due to an increasing number of skin diseases as a result of exposure to ultraviolet (UV) radiation, it is necessary to evaluate the effectiveness of new skin care formulations with broad-spectrum sunscreens.
Objectives:  This study aims to assess the status of nerve fibres in healthy human skin, to quantify effects of UV radiation on nerve endings, and to evaluate neuroprotective effects of new skin care formulations against UV exposure damage.
Methods:  Samples were obtained from 34 female patients enrolled for plastic surgery and were immediately treated (10 min) with three emulsions: Cream 1, Cream 2 (placebo) and a sunscreen with sun protection factor 15 (SPF15). Control samples and those treated with the cream emulsions were exposed to UVA and UVB for 60 min. Nerve fibres were identified by immunofluorescence using a monoclonal antibody (anti-human CD56/NCAM). Cell damage was assessed by image analysis.
Results:  Several cellular nervous structures were identified in the skin samples, including free nerve endings. UVA and UVB significantly decreased (40–60%) density of nerve endings in the control samples and those treated with placebo (Cream 2) or SPF15 (all P  < 0.001). Cream 1 completely blocked effects of UV radiation on nerve endings ( P  > 0.05 vs. control).
Conclusions:  Quantification of cell damage induced by UV radiation provides useful information for identification of new skin care compounds with neuroprotective properties.     

Modification of radiation damage in the canine kidney by hyperthermia: a histologic and functional study

The purpose of this study was to evaluate the effect of hyperthermia on the histologic and functional response of the canine kidney, a late-responding normal tissue, to irradiation. Both kidneys were irradiated. Radiation was delivered in single doses of 0, 10, or 15 Gy. Whole-body hyperthermia was used to produce renal kidney temperatures approximating 42.0 degrees C for 60 min. Thirty-six beagles were placed randomly in the following six treatment groups: control, whole-body hyperthermia alone, 10 Gy alone, 10 Gy + whole-body hyperthermia, 15 Gy alone, and 15 Gy + whole-body hyperthermia. Renal histologic and functional changes were assessed at 1 to 9 months after therapy. No changes were seen in glomerular filtration rate or renal tissue volumes in control or hyperthermia alone groups. Renal vascular and glomerular volumes were not affected significantly by any combination of hyperthermia and/or radiation. In all groups receiving radiation, glomerular filtration rate decreased, percentage renal tubular volume decreased, and interstitial volume increased significantly after therapy. The magnitude of these changes in the functional and histologic response of the kidney and the latent period before expression of this damage were dependent on radiation dose. However, hyperthermia did not modify expression of radiation damage in the kidney based on glomerular filtration rate and histologic quantification of renal tissue components.     

黄河上游环境污染对花背蟾蜍抗氧化酶活性及丙二醛含量的影响

选择黄河上游污染程度较严重的兰州地区和相对无污染的刘家峡地区作为研究样点,比较分析了两地花背蟾蜍（Bufo raddei）肝脏和肾脏中抗氧化酶SOD、CAT和GPx活性及丙二醛（MDA）含量。与刘家峡地区相比,兰州地区花背蟾蜍肝脏的SOD活性升高,CAT和GPx活性极显著降低,肾脏GPx活性显著增高,肝脏和肾脏MDA含量明显高于刘家峡。结果表明,黄河上游环境污染使得花背蟾蜍体内氧化胁迫加重,导致其组织脂质过氧化程度升高。     

Effects of in vitro exposure to power frequency magnetic fields on UV-induced DNA damage of rat lymphocytes

The mechanisms of biological effects of 50/60 Hz (power frequency) magnetic fields (MF) are still poorly understood. There are a number of studies indicating that MF affect biochemical processes in which free radicals are involved, such as the biological objects' response to ultraviolet radiation (UVA). Therefore, the present study was aimed to assess the effect of 50 Hz MFs on the oxidative deterioration of DNA in rat lymphocytes irradiated in vitro by UVA. UVA radiation (150 J/m2) was applied for 5 min for all groups and 50 Hz MF (40 microT rms) exposure was applied for some of the groups for 5 or 60 min. The level of DNA damage was assessed using the alkaline comet assay, the fluorescence microscope, and image analysis. It has been found that the 1 h exposure to MF caused an evident increase in all parameters consistent with damaged DNA. This suggest that MF affects the radical pairs generated during the oxidative or enzymatic processes of DNA repair.     

移植非洲爪蟾胚胎细胞核引起花背蟾蜍成熟卵单性发育的研究

将非洲爪蟾胚胎细胞核移入花背蟾蜍成熟未受精卵后,得到了发育至各期的胚胎。对发育不同的时期的胚胎,进行了乳酸脱氢酶同工酶谱及染色体组型分析,结果一显示其均与受体一致。根据实验分析认为,非洲爪蟾的胚胎细胞进入花背蟾蜍成熟卵后,引起的是花背蟾蜍的单性发育。     

Ultraviolet-B Wavelengths Regulate Changes in UV Absorption of Cleaner Fish Labroides dimidiatus Mucus

High-energy wavelengths in the ultraviolet-B (UVB, 280-315 nm) and the UVA (315-400-nm) portion of the spectrum are harmful to terrestrial and aquatic organisms. Interestingly, UVA is also involved in the repair of UV induced damage. Organisms living in shallow coral reef environments possess UV absorbing compounds, such as mycosporine-like amino acids, to protect them from UV radiation. While it has been demonstrated that exposure to UV (280-400 nm) affects the UV absorbance of fish mucus, whether the effects of UV exposure vary between UVB and UVA wavelengths is not known. Therefore, we investigated whether the UVB, UVA, or photosynthetically active radiation (PAR, 400-700 nm) portions of the spectrum affected the UV absorbance of epithelial mucus and Fulton’s body condition index of the cleaner fish Labroides dimidiatus. We also compared field-measured UV absorbance with laboratory based high-performance liquid chromatography measurements of mycosporine-like amino acid concentrations. After 1 week, we found that the UV absorbance of epithelial mucus was higher in the UVB+UVA+PAR treatment compared with the UVA+PAR and PAR only treatments; after 2 and 3 weeks, however, differences between treatments were not detected. After 3 weeks, Fulton’s body condition index was lower for fish in the UVB+UVA+PAR compared with PAR and UVA+PAR treatments; furthermore, all experimentally treated fish had a lower Fulton’s body condition index than did freshly caught fish. Finally, we found a decrease with depth in the UV absorbance of mucus of wild-caught fish. This study suggests that the increase in UV absorbance of fish mucus in response to increased overall UV levels is a function of the UVB portion of the spectrum. This has important implications for the ability of cleaner fish and other fishes to adjust their mucus UV protection in response to variations in environmental UV exposure.     

Antifungal effects of Ficus sycomorus and Pergularia tomentosa aqueous extracts on some organs in Bufo regularis treated with Aspergillus niger

The antifungal efficacy of Ficus sycomorus and Pergularia tomentosa plant extracts on Bufo regularis experimentally infected with Aspergillus niger was studied. After an oral administration of the pathogen for 15 days, the blood, kidney and liver were examined. Treatment with A. niger produced a reduction in red blood count cells and hemoglobin content. Also, both livers and kidneys revealed marked destruction and degenerative changes. These changes included congestion of blood vessels, leukocytic infiltration, and cytoplasmic vacuolization of the hepatocytes. As well as complete destruction of the cellular boundaries of the tubular epithelia, inflammatory leukocytes between the intertubular spaces, destruction and necrosis in renal tubule cells and the swollen glomeruli with wide glomerular spaces were seen. Pretreatment with F. sycomorus and P. tomentosa plant extracts 1 h prior the administration of A. niger for two weeks improved blood parameters and protected against hepatic and renal damage as observed from histological examination and reduced spore numbers in culture media on these organs.     

The effects of desferrioxamine and quercetin on hepatic ischemia-reperfusion induced renal disturbance

BACKGROUND: The aim of this study was to analyze the effects of 45min of hepatic ischemia and 1h of reperfusion on renal oxidative stress parameters, on renal tissue damage, and the role of Desferrioxamin (Dfx) and Q on these parameters. METHODS: Thirty Wistar albino rats were randomized to five groups. Group I was the control group. Group II received no treatment. Groups III and IV received intramuscular injections of desferrioxamine (100mg/kg) and quercetin (50mg/kg), respectively. Group V was administered Dfx and quercetin in combination. After treatment for 3 days, groups II, III, IV, and V were exposed to total hepatic ischemia for 45min. Plasma alanine aminotransferase levels, renal malondialdehyde and reduced glutathione (GSH) activities were measured after reperfusion for 1h. Histopathological and ultrastructural analysis of renal tissues was carried out. RESULTS: Plasma creatinine and BUN levels were markedly increased in the IR group and pretreated groups. Kidney MDA increased in the IR group, Q and Dfx+Q significantly decreased kidney MDA Kidney GSH levels markedly decreased in the IR group, Dfx significantly increased kidney GSH. No evidence of overt injury was observed in any renal tissue under light and electron microscopy. CONCLUSIONS: Our data demonstrated that 45min of hepatic ischemia and 1h of reperfusion may alter renal functions and may cause oxidative stress on renal tissue. Q and Dfx seem to have a beneficial effect via the GSH system and modulation of MDA levels.