3-MST mRNA在大鼠延髓的表达以及急性缺氧对其基因表达的影响

目的探讨3-巯基丙酮酸硫转移酶（3-mercaptopyruvate sulfurtransferase,3-MST）mRNA在正常、急性缺氧及急性缺氧加外源性HzS条件下的表达情况。方法21只SD大鼠随机等分为正常对照组、急性缺氧组和急性缺氧＋NaHS（H2S供体）组。建立大鼠急性缺氧模型,采用反转录聚合酶链反应（RT—PCR）技术,观察各组大鼠延髓3-MST mRNA的表达水平。结果正常大鼠延髓有3-MST mRNA表达;给予急性缺氧刺激后,大鼠延髓3-MST mRNA表达量明显增加（P〈0．05）;急性缺氧＋NaHS组3-MST mRNA表达量比急性缺氧组明显减少（P〈O．05）。结论3-MST mRNA存在于正常成年大鼠延髓组织中,急性缺氧可上调其表达,外源性H2S可抑制由缺氧所引起的3-MST mRNA表达的增加,提示3-MST—H2S途径可能参与急性缺氧大鼠延髓呼吸中枢缺氧损伤保护作用及节律性呼吸的中枢性调节。     

内源性硫化氢测定在心血管疾病中的应用

硫化氢（H2S）是一种无色气体,有很强的臭鸡蛋味。人类认识并研究其毒性作用已有300多年,已被确定为内源性气体信号分子。低水平的内源性硫化氢是高同型半胱氨酸血症时动脉粥样硬化和血栓并发症的重要原因。内源性硫化氢系统与许多生理及病理生理过程有关。本文就内源性硫化氢的生化特性、检测方法、在心血管系统的生理作用、作用机制及病理生理意义进行综述。     

硫化氢对慢性低氧高二氧化碳模型大鼠学习记忆的影响

目的：探讨硫化氢对慢性低O2高CO2模型大鼠学习记忆的影响。方法：经Morris水迷宫训练淘汰后的24只SD大鼠随机分为3组：正常对照（NC）组,低O2高CO2＋生理盐水（HHSS）组,低O2高CO2＋硫氢化钠（HHSH）组。HHSH组和HHSS组每天置常压低O2高CO2舱内8h,每周6d,共4周观察,4周后Morris水迷宫检查空间学习记忆变化,测定大鼠肺动脉平均压（mPAP）和右心室壁（RV）/左心室加室间隔（LV＋S）比值、血浆中硫化氢浓度。结果：①HHSS组与NC组相比,mPAP和RV/（LV＋S）比值升高,血浆中硫化氢浓度降低,平均逃避潜伏期和游泳总距离延长,穿越平台的次数减少（均P〈0.05）;②HHSH组与HHSS组相比,mPAP和RV/（LV＋S）比值降低,血浆中硫化氢浓度升高,平均逃避潜伏期和游泳总距离缩短（均P〈0.05）。结论：硫化氢可以改善慢性低O2高CO2模型大鼠的学习记忆障碍。     

MAPKs在硫化氢抗大鼠肢体缺血再灌注所致肺损伤中的作用

目的观察丝裂原活化蛋白激酶（MAPKs）在外源性硫化氢（H2S）抗大鼠肢体缺血再灌注（IR）所致肺损伤中的作用.方法健康SD大鼠,随机分为四组（每组n=8）：对照组（Control）,Control＋NaHS组,IR组和IR＋NaHS组.应用双大腿根部止血带复制大鼠双后肢缺血及再灌注后肺损伤模型.Control和IR组动物分别于再灌注前10 min和相应的对照时间点腹腔注射无菌生理盐水（0.5 mL/kg）;IR＋NaHS和Control＋NaHS组动物分别于再灌注前10 min和相应的对照时间点腹腔注射NaHS（28μmol/kg）;观察大鼠肺组织学、肺组织中中性粒细胞（PMN）数目、肺组织湿重和干重之比（W/D）、丙二醛（MDA）含量以及动物生存情况等变化.应用Westernblotting检测肺组织中三种磷酸化MAPKs-细胞外信号调节激酶（ERK）、c-Jun氨基末端激酶（JNK）和p38表达的变化.结果与Contorl组相比,IR组动物死亡率、肺组织PMN数目、W/D、MDA含量以及磷酸化ERK、JNK和p38表达均显著增高（P〈0.05）;与IR组相比,IR＋NaHS组动物死亡率、肺组织中PMN数目、W/D和MDA含量均显著降低、肺损伤减轻,磷酸化ERK表达显著增高、p38表达显著降低（P〈0.05）,JNK表达无显著变化.结论 MAPKs信号通路参与了外源性H2S抗大鼠肢体IR所致肺损伤作用的分子机制.     

The oxidative damage and inflammatory response induced by lead sulfide nanoparticles in rat lung

Lead sulfide nanoparticles (PbS NPs) are one important nanoparticle materials which is widely used in photoelectric production, but its potential health hazard to respiratory system is not clear. This study aimed to explore the possible mechanism of lung injury induced by PbS NPs. Male SD rats were treated with nanoparticles of 60 nm and 30 nm lead sulfide. The main methods were detecting the vigor of superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) and the content of malondialdehyde (MDA) in both blood and lung tissues and observing the pathological changes in lung tissue. PbS NPs suppressed the activity of SOD and T-AOC, and increased serum MDA content (P < 0.05); both effects were observed together in lung tissues of 30-nm group (P < 0.05) accompanied by an obviously inflammatory response. PbS NPs induced oxidative damage and inflammatory response in lung tissue, which may be an underlying mechanism for its pulmonary toxicity. Additionally, the toxicity of PbS NPs was closely related with the size of nanoparticles.     

THE MOUSE EAR MODEL OF CUTANEOUS SULFUR MUSTARD INJURY

The mouse ear inflammation model was used to establish simple endpoints of skin injury following cutaneous exposure to sulfur mustard (bis(2- chloroethyl)sulfide, HD). Mouse ear edema and histopathologic response to a single topical application of 5 muL of 8, 16, 32, 64, or 128 mg/mL HD in dichloromethane was evaluated at 12, 18, and 24 h postexposure. Edema response was determined from weighed 8 mm diameter skin punch biopsies taken from the center of exposed and control ears. Key light microscopic histopathologic changes assessed on the inner (exposed side) and outer surfaces (contralateral side) of the exposed ear included epidermal necrosis (EN) and epidermal-dermal separation (subepidermal blister, SEB). HD produced statistically significant (p <. 05) dose- and time-dependent changes in edema and histopathologic features. A comparative evaluation of the endpoint responses from the various challenge doses indicated that a dose of 0.16 mg/ear HD evaluated at 24 h postexposure would be optimal for future studies using this mouse ear vesicant model (MEVM) to screen pharmacological compounds that may protect against HD-induced skin damage.     

Metformin raises hydrogen sulfide tissue concentrations in various mouse organs

BackgroundThe epidemic of diabetes mellitus type 2 forces to intensive work on the disease medication. Metformin, the most widely prescribed insulin sensitizer, exerts pleiotropic actions on different tissues by not fully recognized mechanisms. Hydrogen sulfide (H₂S) is involved in physiology and pathophysiology of various systems in mammals and is perceived as a potential agent in the treatment of different disorders. The interaction between biguanides and H₂S is unknown. The aim of the study is to assess the influence of metformin on the H₂S tissue concentrations in different mouse organs.MethodsAdult SJL female mice were administered intraperitoneally 100 mg/kg b.w. per day of metformin (group D1, n = 6) or 200 mg/kg b.w. per day of metformin (group D2, n = 7). The control group (n = 6) received physiological saline. The measurements of the free and acid-labile H₂S tissue concentrations were performed with Siegel spectrophotometric modified method.ResultsThere was a significant progressive increase in the H₂S concentration along with the rising metformin doses as compared to the control group in the brain (D1 by 103.6%, D2 by 113.5%), in the heart (D1 by 11.7%, D2 by 27.5%) and in the kidney (D1 by 7.1%, D2 by 9.6%). In the liver, massive H₂S accumulation was observed in the group D1 (increase by 420.4%), while in the D2 group only slight H₂S level enhancement was noted (by 12.5%).ConclusionOur experiment has shown that metformin administration is followed by H₂S tissue concentrations increase in mouse brain, heart, kidney and liver.     

Carotenoid biomarkers in Namibian shelf sediments: Anoxygenic photosynthesis during sulfide eruptions in the Benguela Upwelling System

Aromatic carotenoid-derived hydrocarbon biomarkers are ubiquitous in ancient sediments and oils and are typically attributed to anoxygenic phototrophic green sulfur bacteria (GSB) and purple sulfur bacteria (PSB). These biomarkers serve as proxies for the environmental growth requirements of PSB and GSB, namely euxinic waters extending into the photic zone. Until now, prevailing models for environments supporting anoxygenic phototrophs include microbial mats, restricted basins and fjords with deep chemoclines, and meromictic lakes with shallow chemoclines. However, carotenoids have been reported in ancient open marine settings for which there currently are no known modern analogs that host GSB and PSB. The Benguela Upwelling System offshore Namibia, known for exceptionally high primary productivity, is prone to recurrent toxic gas eruptions whereupon hydrogen sulfide emanates from sediments into the overlying water column. These events, visible in satellite imagery as water masses clouded with elemental sulfur, suggest that the Benguela Upwelling System may be capable of supporting GSB and PSB. Here, we compare distributions of biomarkers in the free and sulfur-bound organic matter of Namibian shelf sediments. Numerous compounds—including acyclic isoprenoids, steranes, triterpanes, and carotenoids—were released from the polar lipid fractions upon Raney nickel desulfurization. The prevalence of isorenieratane and β-isorenieratane in sampling stations along the shelf verified anoxygenic photosynthesis by low-light-adapted, brown-colored GSB in this open marine setting. Renierapurpurane was also present in the sulfur-bound carotenoids and was typically accompanied by lower abundances of renieratane and β-renierapurpurane, thereby identifying cyanobacteria as an additional aromatic carotenoid source.

Lipid biomarkers sequestered in sediments provide valuable information about the communities that occupy the overlying water column. Terpenoid membrane lipids and photosynthetic pigments with preservable hydrocarbon cores can be recognized in rocks and oils to reveal microbial communities that lived in the geologic past. Previous studies have shown that aromatic carotenoids produced by anoxygenic phototrophic green sulfur bacteria (GSB) and purple sulfur bacteria (PSB) are particularly useful in this respect because they signify strong redox gradients in water bodies and in microbial mats. Moreover, aromatic carotenoids are notably abundant in organic matter that was deposited during mass extinction events (1, 2) and during periods of ocean anoxia (3–7). More recently, a study that examined carotenoid distribution through geologic time found that, rather than just recording significant episodes of global ocean anoxia and extreme environmental and geobiological change, sedimentary aromatic carotenoids were considerably more prevalent through time and across a diversity of ancient environments, thereby exposing the enigma that appropriate modern analogs are lacking (4).Research on modern environments and cultured microbes reveals that the occurrence of aromatic carotenoids is determined by the microbial community composition, water chemistry, redox structure of the water column, and the prevailing light regime. The predominant microbial sources of aromatic carotenoids include some members of the Chromatiaceae (i.e., PSB) and Chlorobiaceae (i.e., GSB) (8). More recently, culture studies and the distributions of genes that code for carotenoid biosynthesis show that actinobacteria and cyanobacteria produce aromatic carotenoids (9–15). These carotenoids are also prominent in marine sponges and some other invertebrates, where it is likely they are biosynthesized by bacterial symbionts (16, 17). Phototrophic bacteria have carotenoid distributions tuned to the light regime in which they live. Some members of the Chromatiaceae use the pigment okenone as their primary aromatic carotenoid to harvest light in the range 500 to 520 nm, thereby allowing them to access light not filtered out by water or other aquatic phototrophs (18, 19). Clades of GSB produce chlorobactene, β-isorenieratene, and isorenieratene to harvest photons at the green to blue end of the light spectrum and, potentially, to protect against photobleaching or reactive oxygen species (20–24). The other essential requirements for GSB and PSB are the absence of oxygen and a supply of reduced sulfur compounds, such as hydrogen sulfide, to serve as an electron donor during photosynthesis. However, while PSB can tolerate and perhaps benefit from low concentrations of O₂, GSB are strict anaerobes (20, 25, 26).Carotenoid occurrences in modern environments serve as analogs for interpreting fossil hydrocarbons in ancient settings. Meromictic lakes with shallow chemoclines provide examples for the type of environments where PSB and GSB flourish today and where we might expect to find okenane and chlorobactane in the fossil record (27–30). In contrast, large, restricted basins and fjords with deep chemoclines are seen as analog environments where isorenieratane would be the dominant carotenoid (31–33). Even so, modern analog environments rarely have carotenoid inventories that precisely mirror fossil distributions, and unrestricted marine environments are noticeably absent from suitable modern analogs, hampering the interpretation of GSB and PSB carotenoids in ancient marine sediments (4).Reduced sulfur has a dual role. Not only is it an electron source for the growth of anoxygenic photosynthetic bacteria, but it also facilitates the diagenetic processes leading to carotenoid preservation. Sulfide and other reduced sulfur species serve as reducing and cross-linking agents, as has been widely demonstrated through the identification and prevalence of organo-sulfur compounds (OSC) in the geologic record (34, 35), including fossil carotenoids sequestered as OSC (36, 37). As a result, mild chemical desulfurization of polar lipid fractions can liberate an abundance of taxonomically informative hydrocarbons, allowing their analysis by gas chromatography (GC) (38, 39). Additionally, sulfide can reduce double bonds in the polyunsaturated, isoprenoid chains of carotenoids during early diagenesis in the water column and recent sediments (40). Accordingly, thorough studies of the sedimentary lipid inventory of marine settings should analyze both the free and sulfur-bound fractions to avoid missing compounds that are sequestered in the macromolecular fraction.In the present work, we investigated the carotenoids that are preserved in sediments underlying the Benguela Upwelling System (BUS) offshore Namibia, which is a coastal marine environment noted for its high primary productivity, sulfide eruption events, and sediments rich in organic compounds, which record a wide range of lipid biomarkers for the prevailing plankton (41), including hopanoids and other compounds preserved as sulfur-bound lipids (42–44). Furthermore, satellite imagery has identified recurrent sulfur and sulfide plumes (45–47) with corresponding evidence of an active sulfur cycle (43, 48–51) and, therefore, the potential to support anoxygenic photosynthesis by GSB and PSB. Here, we report and compare the distributions of acyclic isoprenoids, steroids, triterpenoids, and carotenoids in the free and sulfur-bound hydrocarbons present in solvent extracts of the underlying sediments.     

硫化氢对抗七叶皂苷对于HK-2细胞的毒性作用

目的 研究硫化氢（H2S）对七叶皂苷钠（SA）细胞毒性的保护作用.方法 培养HK-2细胞分别建立H2S处理[培养基中添加H2S的供体硫氢化钠（NaHS）]和H2S关键合成酶胱硫醚β合成酶（CBS）、胱硫醚γ裂解酶（CSE）的抑制剂炔丙基甘氨酸（PPG）处理的实验模型.CCK-8实验检测细胞存活率;流式细胞凋亡实验检测细胞凋亡率.结果 SA处理HK-2细胞24h后,细胞存活率为（48.21±3.57）％,细胞凋亡率为（40.8±1.41）％.同时给予SA和NaHS处理,HK-2细胞存活率[（74.35±3.62）％]升高,凋亡率[（17.7±0.55）％]降低（P＜0.01）;相反,同时给予SA和PPG处理,对HK-2细胞的毒性作用增强,细胞存活率[（19.67±2.31）％]降低,细胞凋亡率[（76.91±2.36）％]升高（P＜0.01）.结论 H2S能对抗SA对HK-2细胞的毒性作用,抑制细胞凋亡.