Fe3O4纳米酶对白念珠菌的体外抑制实验研究

【摘要】 目的 研究Fe3O4纳米酶对白念珠菌的抗菌作用。方法 改进水热合成法，制备Fe3O4纳米酶。以0.5 g/L Fe3O4纳米酶和0.1% H2O2与菌液共培养，分为纳米酶组、H2O2组、联合组（纳米酶 + H2O2共处理），以未做处理菌液为对照组。4组菌液以沙氏液体培养基培养，每隔2 h检测600 nm处吸光度（A值），观察白念珠菌生长情况。取4组菌液共处理2 h，扫描电镜观察各组白念珠菌形态；涂板后，于36 ℃培养48 h，观察菌落形成情况并计数，计算抑菌率。多组间均数比较采用单因素方差分析，组间两两比较采用LSD-t检验。结果 对照组白念珠菌具有相对稳定的生存曲线，而纳米酶组、H2O2组、联合组白念珠菌的生长均受到抑制。4组菌落计数分别为124 830 ± 45 170、86 330 ± 13 960、91 670 ± 31 370、30 330 ± 3010，差异有统计学意义（F = 9.41，P < 0.05），联合组低于对照组（t = 4.63，P < 0.05）。H2O2组、纳米酶组、联合组抑菌率分别为30.84% ± 5.00%、26.57% ± 11.24%、75.70% ± 2.42%，差异有统计学意义（F = 9.413，P < 0.01），联合组高于H2O2组、纳米酶组（t = 8.08、4.27，P < 0.01），差异均有统计学意义。扫描电镜观察，经过处理后菌体形态发生皱缩、破裂甚至崩解等改变。结论 Fe3O4纳米酶联合H2O2对白念珠菌抑菌效果明显。     

PI3K/AKT pathway mediates the antidepressant- and anxiolytic-like roles of hydrogen sulfide in streptozotocin-induced diabetic rats via promoting hippocampal neurogenesis

We have previously demonstrated that hydrogen sulfide (H₂S), the third endogenous gasotransmitter, ameliorates the depression- and anxiety-like behaviors in diabetic rats, but the underlying mechanism remains unclear. The present was aimed to investigate whether the hippocampal phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway mediates H₂S-ameliorated depression- and anxiety-like behaviors in diabetic rats by improving the hippocampal neurogenesis. The depression-like behaviors were examined by Tail suspension test (TST), the anxiety-like behaviors were examined by Elevated plus maze test (EPM), and the locomotor activity was detected by Open Field Test (OFT). The expressions of doublecortin (DCX), neuron-specific nuclear protein (NeuN), glial fibrillary acidic protein (GFAP), p-AKT, and AKT in the hippocampus were determined by Western blot analysis. Results showed that NaHS, a donor of exogenous H₂S, not only activated the hippocampal PI3K/AKT pathway, as evidenced by the increase of phosphorylated AKT, but also favorably reversed streptozotocin (STZ)-disturbed hippocampal neurogenesis, as evidenced by the increases in the expressions of DCX and NeuN as well as the decrease in the expression of GFAP in the hippocampus of STZ-induced diabetic rats. Furthermore, inhibited PI3K/AKT pathway by LY294002 significantly abolished H₂S-exerted the improvement of hippocampal neurogenesis and the antidepressant- and anxiolytic-like effects in the STZ-induced diabetic rats. Taken together, these results uncover that the activation of hippocampal PI3K/AKT pathway plays an important role to restore hippocampal neurogenesis and subsequently to mediate the antidepressant- and anxiolytic-like roles of H₂S in STZ-induced diabetic rats and enhance our understanding of the robustness of H₂S as a therapeutic strategy for treatment of depression in diabetes mellitus.     

蛋氨酸限制提高内源性H2S活性延缓衰老的机制研究进展

蛋氨酸限制(Methionine restriction,MetR)作为饮食限制的方法之一,能够改善多种无脊椎动物、啮齿类动物及包括人类灵长类动物的衰老及其相关疾病。但MetR对衰老的具体调节作用机制尚未完全明确,目前除了与饮食限制的共有机制以外,越来越多的研究表明内源性硫化氢(Endogenous hydrogen sulfide,H2S)可能是其发挥效应的主要机制。硫化氢作为水溶性和脂溶性的小分子气体,在延缓衰老进程和改善衰老相关疾病中具有重要意义。本文阐述了MetR通过提高内源性H2S的活性延缓衰老的机制及相关研究。     

Evidence-based pathogenesis and treatment of ulcerative colitis: A causal role for colonic epithelial hydrogen peroxide

In this comprehensive evidence-based analysis of ulcerative colitis (UC), a causal role is identified for colonic epithelial hydrogen peroxide (H₂O₂) in both the pathogenesis and relapse of this debilitating inflammatory bowel disease. Studies have shown that H₂O₂ production is significantly increased in the non-inflamed colonic epithelium of individuals with UC. H₂O₂ is a powerful neutrophilic chemotactic agent that can diffuse through colonic epithelial cell membranes creating an interstitial chemotactic molecular “trail” that attracts adjacent intravascular neutrophils into the colonic epithelium leading to mucosal inflammation and UC. A novel therapy aimed at removing the inappropriate H₂O₂ mediated chemotactic signal has been highly effective in achieving complete histologic resolution of colitis in patients experiencing refractory disease with at least one (biopsy-proven) histologic remission lasting 14 years to date. The evidence implies that therapeutic intervention to prevent the re-establishment of a pathologic H₂O₂ mediated chemotactic signaling gradient will indefinitely preclude neutrophilic migration into the colonic epithelium constituting a functional cure for this disease. Cumulative data indicate that individuals with UC have normal immune systems and current treatment guidelines calling for the suppression of the immune response based on the belief that UC is caused by an underlying immune dysfunction are not supported by the evidence and may cause serious adverse effects. It is the aim of this paper to present experimental and clinical evidence that identifies H₂O₂ produced by the colonic epithelium as the causal agent in the pathogenesis of UC. A detailed explanation of a novel therapeutic intervention to normalize colonic H₂O₂, its rationale, components, and formulation is also provided.     

硫化氢吸入对心搏骤停复苏大鼠脑蛋白激酶C同工酶的影响

目的探讨吸入硫化氢对心搏骤停复苏大鼠脑蛋白激酶C(PKC)同工酶的影响。方法取清洁级健康SD雄性大鼠60只,采用数字表法,将其随机分为假手术组(10只)、对照组(25只)和硫化氢组(25只)。对照组和硫化氢组采用窒息性心搏骤停后心肺复苏模型,硫化氢组于自主循环恢复后立即吸入含有0.08‰硫化氢的30%氧气1 h。各组大鼠于假手术或自主循环恢复后24 h时,应用神经功能缺损评分(NDS)评价神经功能;于24 h监测PKC同工酶α、βⅠ、βⅡ、δ及ε的活性水平;于7 d计算存活率、计数海马CA1区存活神经细胞。结果 (1)假手术组大鼠全部存活,对照组和硫化氢组存活率分别为45.0%(9/20)和80.0%(16/20),与对照组相比,硫化氢组大鼠存活率明显增加,组间差异有统计学意义(χ2=8.087,P=0.018)。(2)自主循环恢复(ROSC)24 h,与假手术组相比,对照组和硫化氢组NDS评分均明显降低,组间中位数两两比较,差异均有统计学意义[46(43,52)、60(55,68)分比80(80,80),均P0.05];与对照组比较,硫化氢组NDS评分升高,组间差异有统计学意义(P0.05)。(3)ROSC后24 h,与假手术组比较,对照组PKC-α、PKC-βⅠ、PKC-βⅡ和PKC-δ活性水平明显升高,PKC-ε活性水平受到抑制,组间比较差异均有统计学意义[(1.63±0.14)比(1.00±0.02)、(2.00±0.08)比(1.00±0.04)、(1.51±0.10)比(1.00±0.01)、(2.02±0.12)比(1.00±0.02);均P0.05];硫化氢组PKC-α、PKC-βⅠ、PKC-βⅡ、PKC-δ和PKC-ε活性水平的差异无统计学意义(均P0.05);与对照组比较,硫化氢组PKC-α、PKC-βⅠ、PKC-βⅡ和PKC-δ活性水平[分别为(0.94±0.06)、(1.26±0.04)、(0.83±0.02)、(1.04±0.06)]明显下降,PKC-ε水平明显升高[(1.13±0.07)比(0.73±0.04)],组间差异均有统计学意义(均P0.05)。(4)ROSC后7 d,假手术组、对照组和硫化氢组海马CA1区存活神经细胞计数分别为(53±3)、(23±2)和(34±1)个,与假手术组相比,对照组和硫化氢组存活神经细胞计数均明显降低(均P0.01);与对照组比较,硫化氢组存活神经细胞计数明显升高(P0.01)。结论心搏骤停/心肺复苏后,早期吸入硫化氢可抑制PKC-α、PKC-βⅠ、PKC-βⅡ及PKC-δ激活,促进PKC-ε激活,改善大鼠神经功能和促进神经细胞存活。     

富氢液通过自噬途径下调中波紫外线诱导的HaCaT细胞炎症因子的表达

目的 探讨氢气是否能通过自噬途径调节中波紫外线(UVB)诱导的HaCaT细胞炎症因子的表达.方法 将培养的HaCaT细胞分为空白对照组(不做任何处理),氢气组(仅用富氢培养液培养),1、10、50 mJ/cm2 UVB组,l、10、50 mJ/cm2 UVB+氢气组,50 mJ/cm2 UVB+3甲基腺嘌呤(3MA)组,50 mJ/cm2 UVB+雷帕霉素组,50 mJ/cm2 UVB+ 3MA+氢气组,50 mJ/cm2 UVB+雷帕霉素+氢气组.细胞经过不同处理培养12 h后,噻唑蓝(MTF)法检测细胞增殖,LDH试剂盒检测乳酸脱氢酶(LDH),细胞提取蛋白检测自噬蛋白LC3和Beclin1的表达,上清液用ELISA检测炎症因子肿瘤坏死因子(TNF)α、白细胞介素(IL)-1β、HMGB1和IL-6的水平.结果 与空白对照组相比,UVB诱导的HaCaT细胞LDH释放增多,细胞活力下降,自噬蛋白LC3和Beclin1表达增加,炎症因子TNF-α、IL-1β、HMGB1和IL-6释放增加(均P＜0.05).与UVB组相比,氢气可减少LDH释放,提高细胞活力,自噬蛋白LC3和Beclin1表达进一步增加,炎症因子TNF-α、IL-1β、HMGB1和IL-6表达减少(均P＜ 0.05).与50 mJ/cm2 UVB组相比,50 mJ/cm2 UVB+ 3MA组炎症因子TNF-α、IL-1β、HMGB1和IL-6表达进一步增加(P＜0.05),而50 mJ/cm2 UVB+雷帕霉素组炎症因子TNF-α、IL-1β、HMGB1和IL-6表达减少(P＜0.05).与50 mJ/cm2 UVB+氢气组相比,50 mJ/cm2 UVB+氢气+3MA组炎症因子TNF-α、IL-1β、HMGB1和IL-6表达增加(P＜0.05).结论 UVB照射可以诱发自噬蛋白表达增加;富氢液可以下调UVB诱导的HaCaT细胞炎症因子的表达,而这一过程是通过激活自噬途径实现的.     

Therapeutic concentration of morphine reduces oxidative stress in glioma cell line

Morphine is a potent analgesic opioid used extensively for pain treatment. During the last decade, global consumption grew more than 4-fold. However, molecular mechanisms elicited by morphine are not totally understood. Thus, a growing literature indicates that there are additional actions to the analgesic effect. Previous studies about morphine and oxidative stress are controversial and used concentrations outside the range of clinical practice. Therefore, in this study, we hypothesized that a therapeutic concentration of morphine (1 μM) would show a protective effect in a traditional model of oxidative stress. We exposed the C6 glioma cell line to hydrogen peroxide (H₂O₂) and/or morphine for 24 h and evaluated cell viability, lipid peroxidation, and levels of sulfhydryl groups (an indicator of the redox state of the cell). Morphine did not prevent the decrease in cell viability provoked by H₂O₂ but partially prevented lipid peroxidation caused by 0.0025% H₂O₂ (a concentration allowing more than 90% cell viability). Interestingly, this opioid did not alter the increased levels of sulfhydryl groups produced by exposure to 0.0025% H₂O₂, opening the possibility that alternative molecular mechanisms (a direct scavenging activity or the inhibition of NAPDH oxidase) may explain the protective effect registered in the lipid peroxidation assay. Our results demonstrate, for the first time, that morphine in usual analgesic doses may contribute to minimizing oxidative stress in cells of glial origin. This study supports the importance of employing concentrations similar to those used in clinical practice for a better approximation between experimental models and the clinical setting.     

轻度胃肠炎伴婴幼儿良性惊厥患儿血清硫化氢水平变化的研究

目的 研究轻度胃肠炎伴婴幼儿良性惊厥(BICE)患儿血清硫化氢(H2S)水平的变化及意义.方法 选择住院治疗的42 例BICE 患儿为观察组,同期因单纯急性胃肠炎入院治疗的46 例患儿为对照组.使用分光光度计法检测其血清H2S 水平.结果 观察组患儿血清H2S 水平显著低于对照组(28±12 μmol/L vs45±10 μmol/L,P<0.O1).惊厥发作次数≥ 2 次患儿血清H2S 水平显著低于发作次数<2 次患儿(P<0.O5).BICE 患儿惊厥发作次数与血清H2S 水平呈负相关(r=-0.485,P=0.001);惊厥持续时间≥ 5 min 组患儿的发作时间与血清H2S 水平呈负相关(r=-0.736,P=0.004).结论 内源性H2S 水平的降低可能是BICE 患儿发病原因之一;血清H2S 水平下降程度与惊厥发生的次数及发作超过5 min 的持续时间有关,其临床意义有待于更多的研究证实.     

30%双氧水浸泡后对牙本质中钙/磷含量的影响

目的针对临床型漂白剂在使用中直接接触牙颈部暴露的牙本质和通过牙釉质渗透到牙本质的特点,观察30%双氧水对牙本质中的Ca/P的影响.方法实验组7颗离体牙浸泡在30%双氧水24小时后,对照组5颗离体牙浸泡在生理盐水中24小时后,两组使用OCPC法对浸泡液中的Ca离子含量进行测定,同时运用Fiske-Subbarow法对浸泡液中的磷酸根含量进行测定.然后两组进行统计学比较分析.结果实验组30%双氧水浸泡液中Ca/P含量明显高于对照组(P<0.01).说明在30%双氧水浸泡过程中发生了明显脱矿现象.结论 30%双氧水对牙本质有脱矿作用,建议在使用临床型漂白治疗后应加以再矿化和防龋措施.