Antioxidant activities of Ganoderma lucidum polysaccharides and their role on DNA damage in mice induced by cobalt-60 gamma-irradiation

In this study, the radio-protective effects of Ganoderma lucidum polysaccharides (GLP) were investigated in a mouse animal model exposed to (60)Co gamma-irradiation. Each of three batches of mice were divided into five groups (negative control, positive gamma irradiated control, and low, middle and high dosage GLP groups). Different batches of animals were used to evaluate the impact of GLP on peripheral white blood cell count, immune organ index; DNA damage, lipid peroxidation; micronuclei formation, and nucleated cell count in bone marrow induced by (60)Co gamma-irradiation. DNA strand-break and micronuclei frequency were significantly reduced and glutathione peroxidase activity and nucleated cell count in bone marrow were significantly increased by GLP treatment in a dose-dependent manner. GLP intervention also increased the activity of superoxide dismutase and decreased the level of malondialdehyde in middle and high GLP treatment groups. No adverse effects were observed on peripheral white blood cells and immune organ or body weight in either the control groups or GLP treated gamma exposed mice. These findings suggest that GLP possesses marked antioxidant capacity which plays an important role in the prevention of radiation damage in mice induced by (60)Co gamma-irradiation.     

Effects of Ganoderma lucidum polysaccharides on proliferation and cytotoxicity of cytokine-induced killer cells

AIM: To study the effects (and the mechanisms thereof) of Ganoderma lucidum polysaccharides (Gl-PS) on the proliferation and the anti-tumor activity of cytokine-induced killer (CIK) cells, and to make use of CIK cells as a means to investigate the interactions between Gl-PS and cytokines. METHODS: CIK cells were prepared by using the standard protocol as a positive control. Experimental groups also underwent the standard protocol, except that Gl-PS (400 mg/L or 100 mg/L) was added and the dose of anti-CD3 and interleukin-2 they received was reduced by 50% and 75%, respectively. For negative controls, Gl-PS in the experimental protocol was replaced with soluble starch or methylcellulose (400 mg/L or 100 mg/L). CIK cell proliferation, cytotoxicity, and phenotype were determined by using the Trypan blue exclusion method, MTT assay, and flow cytometry. RESULTS: By synergizing cytokines, Gl-PS (400 mg/L or 100 mg/L) could decrease the amount of cytokine in lymphokine activated killer (LAK) cells and CIK cells culture, but had no significant effect on the proliferation, cytotoxicity, or phenotype of LAK cells, or CIK cells induced by cytokines at higher doses alone, in which CIK cells expanded about 80-fold and the main effectors, CD3+NK1.1+ cells, expanded by more than 15%. The cytotoxicity of CIK cells in experimental groups was 79.3%+/-4.7%, 76.9%+/-6.8% versus the positive control 80.7%+/-6.8% against P815 (P>0.05) and 88.9%+/-5.5%, 84.7%+/-7.9% versus the positive control 89.8%+/-4.5% against YAC-1 (P>0.05). The activity of Gl-PS could mostly be blocked by anti-CR3. CONCLUSION: Gl-PS was shown to be a promising biological response modifier and immune potentiator. The effect of Gl-PS on CIK cells is possibly mediated primarily through complement receptor type 3.     

HPLC determination of four triterpenoids in rat urine after oral administration of total triterpenoids from Ganoderma lucidum

A sensitive and simple high-performance liquid chromatography (HPLC) method was applied for the quantitative determination of four major triterpenoids (ganoderic acids C(2), B, K and H) in rat urine after oral administration of total triterpenoids from Ganoderma lucidum. The urine sample was extracted with dichloromethane-ethyl acetate (90:10) after acidification by hydrochloric acid (0.2 mol/ml). Chromatographic separation was achieved on a Zorbax SB-C(18) column (250 mm x 4.6 mm, 5 microm) at 35 degrees C, with a linear gradient of acetonitrile and 0.03% aqueous phosphoric acid (v/v), at a flow rate of 1.2 ml/min. The four triterpenoids and internal standard (hydrocortisone) were detected at a wavelength 252 nm. The within- and between-day assay coefficients of variation for the four triterpenoids in urine were less than 9% and the extraction recovery of this method was higher than 90%. Using this method, the excretion profile of the triterpenoids in rat urine after oral administration of total triterpenoids of G. lucidum was revealed for the first time.     

Development of a chromatographic fingerprint for the chloroform extracts of Ganoderma lucidum by HPLC and LC-MS

A new high-performance liquid chromatographic (HPLC) fingerprinting method was developed for the quality control of Ganoderma lucidum. Twenty-nine batches obtained from three different origins in China were used to establish the fingerprint. The constituents of these samples were separated with a Kromasil C(18) column (250 mm x 4.6 mm, 5 microm) by linear gradient elution using water-acetic acid (100:0.1, v/v) and acetonitrile as mobile phase components at a flow rate of 0.8 ml/min and detector wavelength at 254 nm. Mean chromatograms and correlation coefficients of samples were calculated by the software "Similarity Evaluation System for Chromatographic Fingerprint of TCM". There were 19 common peaks in this fingerprint. Eleven of these common peaks were tentatively identified with reference to literature data based on their liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS) and UV data. This profile was then successfully used to identify and assess the differences among samples from various origins with the aid of similarity analysis. The diverse similarities among different samples indicated that the quality of G. lucidum was not stable and the products from different areas were inconsistent. All results showed that the developed fingerprint assay was specific and could further serve for quality identification and comprehensive evaluation of G. lucidum.     

段木栽培及袋栽灵芝多糖对体外培养小鼠脾淋巴细胞增殖活性的比较

目的 比较段木栽培灵芝多糖(wood-cultured Ganoderma lucidum polysaccharides, GL-PS-WC) 及袋栽灵芝多糖(bag-cultured Ganoderma lucidum polysaccharides, GL-PS-BC)对体外培养小鼠脾淋巴细胞增殖活性的影响,探讨袋栽灵芝多糖替代段木栽培灵芝多糖的可能性。 方法检测两种灵芝多糖对混合淋巴细胞培养(MLC)反应的影响;观察对刀豆蛋白A (Con A)、细菌脂多糖(LPS)诱导淋巴细胞增殖的影响以及对环孢素A (CsA)、丝裂霉素C(Mit C)、足叶乙苷(VP-16) 等抑制MLC反应的影响。结果当质量浓度为0.2～12.8 mg·L^-1时,两种灵芝多糖均可促进MLC反应,增强Con A或LPS诱导的淋巴细胞增殖,并拮抗CsA, Mit C或VP-16对MLC反应的抑制作用。未发现两种多糖之间有显著性差异。结论GL-PS-WC及GL-PS-BC对体外培养脾淋巴细胞的增殖活性有类似作用。     

Sensitive and selective liquid chromatography-tandem mass spectrometry method for the determination of five ganoderic acids in Ganoderma lucidum and its related species

The present paper describes a novel, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous analysis of ganoderic acids C(2), B, A, H, D in Ganoderma lucidum and its related species. Ganoderma samples were prepared using simple ultrasonic extraction. Chromatographic separation was carried out on an Agilent Zorbax XDB C(18) column (250 mm × 4.6 mm i.d., 5μm) with an isocratic mobile phase consisting of acetonitrile, water and formic acid (42:58:0.5, v/v/v). Mass spectrometric detection was achieved by a triple-quadrupole mass spectrometer equipped with an atmospheric pressure chemical ionization (APCI) interface operating in negative and positive ionization mode via a single within-run polarity switching. Quantitation of five ganoderic acids was performed using selective reaction monitoring (SRM) mode. The intra- and inter-day precision was less than 6.2% and the accuracy ranged from 90.0% to 105.7%. The limit of quantification (LOQ) was 20.0-40.0 ng/mL and the limit of detection (LOD) was 3.0-25.0 ng/mL. With this method, low levels of ganoderic acids in the fruiting bodies of Ganoderma sinense and Ganoderma applanatum were accurately quantified for the first time. Importantly, the method allows unequivocal quantification of the five ganoderic acids in the spores and fruiting bodies of Ganoderma lucidum, whereas the previously published methods have lacked the capability. The method presented will be a powerful tool for quality control of Ganoderma lucidum and its related species.     

Qualitative and quantitative analyses of nucleosides and nucleobases in Ganoderma spp. by HPLC-DAD-MS

A high-performance liquid chromatography-diode array detector-mass spectrometry (HPLC-DAD-MS) analytical method was developed for detection of the nucleosides and nucleobases in two species of Lingzhi, the dried sporophore of Ganoderma lucidum and G. sinense. The method, combining advantages of both DAD and MS, was successfully used to qualitatively identify for six nucleosides namely, adenosine, cytidine, guanosine, inosine, thymidine, uridine and five nucleobases namely, adenine, guanine, hypoxanthine, thymine and uracil in Lingzhi samples. Quantitative analyses showed that uridine was the most abundant nucleoside in these Lingzhi samples and the contents of nine target analytes were found to be different in pileus and stipes of the fruiting bodies and among the different species of G. spp. The established method might apply as an alternative approach for the quality assessment of Lingzhi.     

Potent protective effect of apricot and beta-carotene on methotrexate-induced intestinal oxidative damage in rats.

Several studies have well confirmed the contribution of oxidative stress in the pathogenesis of methotrexate (MTX)-induced damage in the small intestine. Many agents have been tried experimentally to reduce or inhibit the oxidative stress. To our knowledge, there is no study about apricot consumption on the MTX-induced damage in the small intestine. The aim of this study was to determine the possible protective effects of apricot and beta-carotene on MTX-induced intestinal damage in rats. The rats were randomly divided into seven groups as follows; I-control group; II-apricot group; III-beta-carotene group; IV-MTX group; V-apricot+MTX group; VI-beta-carotene+MTX group and VII-apricot+beta-carotene+MTX group. In the MTX group; fusion and shortening in the villus, epithelial desquamation, crypt loss, inflammatory cell infiltration in the lamina propria, goblet cell depletion and microvillar damage were observed in the small intestine. Parallel to histological results, malondialdehyde (MDA) content and myeloperoxidase (MPO) activity were found to be increased, whereas superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GP-x) activities and glutathione (GSH) content were decreased in the MTX group. However, single or combined application of apricot and beta-carotene ameliorated all of these hazordous effects in antioxidant system in MTX-treated groups. In conclusion, our results demonstrate that apricot and/or beta-carotene treatment may protect the impairment of oxidative stress and ameliorate MTX-induced intestine damage at biochemical and histological levels.     

Pirarubicin inhibits multidrug-resistant osteosarcoma cell proliferation through induction of G2/M phase cell cycle arrest

Aim:

Pirarubicin (THP) is recently found to be effective in treating patients with advanced, relapsed or recurrent high-grade osteosarcoma. In this study, the effects of THP on the multidrug-resistant (MDR) osteosarcoma cells were assessed, and the underlying mechanisms for the disruption of cell cycle kinetics by THP were explored.

Methods:

Human osteosarcoma cell line MG63 and human MDR osteosarcoma cell line MG63/DOX were tested. The cytotoxicity of drugs was examined using a cell proliferation assay with the Cell Counting Kit-8 (CCK-8). The distribution of cells across the cell cycle was determined with flow cytometry. The expression of cell cycle-regulated genes cyclin B1 and Cdc2 (CDK1), and the phosphorylated Cdc2 and Cdc25C was examined using Western blot analyses.

Results:

MG63/DOX cells were highly resistant to doxorubicin (ADM) and gemcitabine (GEM), but were sensitive or lowly resistant to THP, methotrexate (MTX) and cisplatin (DDP). Treatment of MG63/DOX cells with THP (200–1000 ng/mL) inhibited the cell proliferation in time- and concentration-dependent manners. THP (50–500 ng/mL) induced MG63/DOX cell cycle arrest at the G₂/M phase in time- and concentration-dependent manners. Furthermore, the treatment of MG63/DOX cells with THP (200–1000 ng/mL) downregulated cyclin B1 expression, and decreased the phosphorylated Cdc2 at Thr¹⁶¹. Conversely, the treatment increased the phosphorylated Cdc2 at Thr¹⁴/Tyr¹⁵ and Cdc25C at Ser²¹⁶, which led to a decrease in Cdc2-cyclin B1 activity.

Conclusion:

The cytotoxicity of THP to MG63/DOX cells may be in part due to its ability to arrest cell cycle progression at the G₂/M phase, which supports the use of THP for managing patients with MDR osteosarcoma.     

Carbazolequinone induction of caspase-dependent cell death in Src-overexpressing cells

We previously reported that RSV-transformed quail neuroretina cells (QNR-ts68) were highly resistant to apoptosis provoked by serum withdrawal, and that this property was due to v-Src kinase activity. The present study investigates the cytotoxic effect and the functional mechanism of carbazolequinone-mediated cell death in this system. QNR-ts68 cells were subjected to carbazolequinone treatment and both growth inhibition and cell death induction were examined using formazan assays. Cell death mechanism (both apoptosis and necrosis) was confirmed through phosphatidyl serine exposure and propidium iodide incorporation. Furthermore, the effect of active carbazolequinone was inhibited by a pan caspase inhibitor. Cytofluorimetric and immunofluorescence data demonstrated the activation of caspase-3 and the involvement of mitochondria. Therefore, this study clearly indicates that carbazolequinones could induce cell death in transformed cells displaying high levels of antiapoptotic tyrosine kinase activity. Further investigations would be necessary to elucidate the mechanisms by which these carbazolequinones act as antitumor agents.     

黄精多糖对糖尿病小鼠降糖作用及肠道影响的研究

目的 研究黄精多糖对2型糖尿病小鼠降血糖作用及其对肠道菌群和小肠病理结构的影响。方法 雄性小鼠50只,除10只正常饲养外,其余以高脂高糖饲料喂养6周,腹腔注射链脲佐菌素制备2型糖尿病小鼠模型,建模成功后随机分为4组：模型组、黄精多糖高、中、低(500、250、125 mg/kg)组,模型组小鼠给予生理盐水。记录各组小鼠体重和血糖值变化。4周后,收集粪便,进行16S rRNA高通量测序,HE染色观察小肠组织病理结构变化。结果 小鼠在糖尿病状态下体重下降,给予黄精多糖高、中、低剂量后小鼠体重分别增加14.24%、11.97%和8.78%,血糖值分别降低26.6%、22.3%和13.3%。此外,小肠病理组织学排列错乱和肿胀现象有所改善。模型组和黄精多糖组之间的肠道微生物存在显著差异,模型组中疣微菌门显著增多,而健康组和黄精多糖灌胃组中厚壁菌门和拟杆菌门的微生物丰度更高。结论 黄精多糖对糖尿病小鼠具有显著的降血糖作用,且对其肠道具有一定保护作用,其机制可能通过增加有益菌丰富度,提高小鼠免疫功能来实现的,且呈一定剂量效应关系,其免疫功能有待进一步研究。     

Effect of salivary proteins on the transport of tannin and quercetin across intestinal epithelial cells in culture

Polyphenols including tannins and flavonoids are common in plant foods. While tannins may be deleterious to animals, flavonoids can have beneficial effects on the cardio-vascular system. Since salivary proteins can form complexes with polyphenols and thereby interfere with their intestinal absorption, the effect of salivary proteins on transport of tannins and flavonoids across intestinal epithelial cells (Caco-2 cells) was investigated. In presence of the salivary protein Histatin5 (Hst5) the rate of transport (dC/dt) of pentagalloyl glucose (5GG), a tannic acid, across Caco-2 cells in culture was reduced maximally 3.6-fold to 5x10(-7)microM/s in apical to basolateral direction. Replacing the basolateral salt solution with serum caused a 13-fold increase in dC/dt of 5GG in the absence of Hst5, but addition of Hst5 decreased dC/dt l4-fold. Transport of 5GG in basolateral to apical direction was decreased in half in the presence of Hst5. Decreases in dC/dt were closely paralleled by formation of insoluble 5GG-Hst5 complexes. In contrast, Hst5 and 1B4, a salivary proline-rich protein, had little if any effect on the transepithelial transport of the flavonoid quercetin in apical to basolateral as well as basolateral to apical direction. Taken together with previous studies [Cai K, Hagerman AE, Minto RE, Bennick A. Decreased polyphenol transport across cultured intestinal cells by a salivary proline-rich protein. Biochem Pharmacol 2006;71:1570-80] it appears that although Hst5 and 1B4 are synthesized in salivary glands they have an important biological function in the intestines as scavenger molecules preventing uptake of tannin but without notably affecting absorption of flavonoids.     

DNA damage-triggered apoptosis: critical role of DNA repair, double-strand breaks, cell proliferation and signaling

Genotoxic DNA damaging agents may activate both membrane death receptors and the endogenous mitochondrial damage pathway leading to cell death via apoptosis. Here, apoptotic responses in cells exhibiting a defect in various DNA repair pathways such as alkyltransferase, base excision repair, nucleotide excision repair and mismatch repair are reviewed. The HSVTk/ganciclovir and VZV/BVDU suicide system will also be discussed. Data are available to show that critical DNA damage triggers apoptosis in a DNA replication dependent way by activating the mitochondrial damage pathway in fibroblasts. It is proposed that DNA double-strand breaks (DSBs) are common ultimate apoptosis-triggering lesions arising from primary DNA lesions during DNA replication. Thus, DNA replication is a necessary component in DNA damage-triggered apoptosis, at least in fibroblasts treated with genotoxins not inducing DSBs themselves. For methylating agents inducing O(6)-methylguanine, an additional requirement is mismatch repair provoking DSB formation that triggers Bcl-2 decline and caspase-9/-3 activation. This occurs independent of p53 since most of the repair deficient cell lines under study were mutated for p53. Moreover, p53 knockout fibroblasts are more sensitive to methylating agents and UV light than p53 wt cells, suggesting p53 to play a protective rather than a pro-apoptotic role in this cell system, probably by its involvement in DNA repair. However, for lymphoblastoid cells p53 wt variants are more sensitive to DNA damage indicating that p53 participates in apoptotic signaling in a cell type-specific fashion. The role of topoisomerase II inhibitors and c-Fos/AP-1 in apoptosis will also be discussed.     

The L-3,4-dihydroxyphenylalanine transporter in human and rat epithelial intestinal cells is a type 2 hetero amino acid exchanger

Information on the intestinal transport of L-3,4-dihydroxyphenylalanine (L-DOPA) is scarce. We present here the functional characteristics and regulation of the apical inward L-DOPA transport in two intestinal epithelial cell lines (human Caco-2 and rat IEC-6). The inward transfer of L-DOPA and L-leucine was promoted through an energy-driven system but with different sensitivity to extracellular Na(+) concentration: a minor component of L-leucine uptake (approximately 25%) was found to require extracellular Na(+) in comparison with L-DOPA transport which was Na(+)-independent. L-DOPA and L-leucine uptake was insensitive to N-(methylamino)-isobutyric acid, but competitively inhibited by 2-aminobicyclo(2,2,1)-heptane-2-carboxylic acid (BCH). L- and D-neutral amino acids, but not acidic and basic amino acids, markedly inhibited L-DOPA and [(14)C]L-leucine accumulation in both cell lines. The [(14)C]L-DOPA and [14C]L-leucine outward were markedly increased by L-leucine and BCH present in extracellular medium, but not by L-arginine. In both cell lines, L-DOPA transport was stimulated by acidic pH in comparison with [(14)C]L-leucine inward which was pH-independent. In conclusion, it is likely that system B(0) might be responsible for the Na(+)-dependent uptake of L-leucine in Caco-2 and IEC-6 cells, whereas sodium-independent uptake of L-leucine and L-DOPA may include system type 1 and type 2 L-amino acid transporter (LAT1 and LAT2), the activation of which results in trans-stimulation of substrates outward transfer.     

Protective effect of dextromethorphan against endotoxic shock in mice

Dextromethorphan (DM) is a dextrorotatory morphinan and an over-the-counter non-opioid cough suppressant. We have previously shown that DM protects against LPS-induced dopaminergic neurodegeneration through inhibition of microglia activation. Here, we investigated protective effects of DM against endotoxin shock induced by lipopolysaccharide/d-galactosamine (LPS/GalN) in mice and the mechanism underlying its protective effect. Mice were given multiple injections of DM (12.5 mg/kg, s.c.) 30 min before and 2, 4 h after an injection of LPS/GalN (20 microg/700 mg/kg). DM administration decreased LPS/GalN-induced mortality and hepatotoxicity, as evidenced by increased survival rate, decreased serum alanine aminotransferase activity and improved pathology. Furthermore, DM was also effective when it was given 30 min after LPS/GalN injection. The protection was likely associated with reduced serum and liver tumor necrosis factor alpha (TNF-alpha) levels. DM also attenuated production of superoxide and intracellular reactive oxygen species in Kupffer cells and neutrophils. Real-time RT-PCR analysis revealed that DM administration suppressed the expression of a variety of inflammation-related genes such as macrophage inflammatory protein-2, CXC chemokine, thrombospondin-1, intercellular adhesion molecular-1 and interleukin-6. DM also decreased the expression of genes related to cell-death pathways, such as the DNA damage protein genes GADD45 and GADD153. In summary, DM is effective in protecting mice against LPS/GalN-induced hepatotoxicity, and the mechanism is likely through a faster TNF-alpha clearance, and decrease of superoxide production and inflammation and cell-death related components. This study not only extends neuroprotective effect of DM, but also suggests that DM may be a novel compound for the therapeutic intervention for sepsis.     

Anti-cancer effect of Cordyceps militaris in human colorectal carcinoma RKO cells via cell cycle arrest and mitochondrial apoptosis

Background

Cordyceps militaris has been used as a traditional medicine in Asian countries for a long time. Different types of Cordyceps extract were reported to have various pharmacological activities including an anti-cancer effect. We investigated the inhibitory effect of Cordyceps militaris ethanol extract on a human colorectal cancer-derived cell line, RKO.

Methods

RKO cells were treated with various concentrations of nucleosides-enriched ethanol extract of Cordyceps militaris for 48 h and cytotoxicity was measured using a CCK-8 assay. Then, xenograft Balb/c nude mice were injected with RKO cells and subsequently orally administered with ethanol extract of Cordyceps militaris every day for 3 weeks to examine the inhibitory effect on tumor growth. Lastly, the effect of Cordyceps militaris on cell cycle as well as apoptosis was measured using flow cytometry. Also, the expression of p53, caspase 9, cleaved caspase-3, cleaved PARP, Bim, Bax, Bak, and Bad were detected using western blot assay.

Results

RKO cells were highly susceptible to the ethanol extract of Cordyceps militaris (CME) and the growth of RKO cells-derived tumor was significantly delayed by the treatment of Cordyceps militaris. Cordyceps militaris induced cell cycle arrest in G2/M phase (untreated; 20.5 %, CME 100 μg/ml; 61.67 %, CME 300 μg/ml; 66.33 %) and increased early apoptosis (untreated; 1.01 %, CME 100 μg/ml; 8.48 %, CME 300 μg/ml; 18.07 %). The expression of p53, cleaved caspase 9, cleaved caspase-3, cleaved PARP, Bim, Bak, and Bad were upregulated by the treatment of Cordyceps militaris.

Conclusion

Ethanol extract of Cordyceps militaris was highly cytotoxic to human colorectal carcinoma RKO cells and inhibited the growth of tumor in xenograft model. The anti-tumor effect of Cordyceps militaris was associated with an induction of cell cycle arrest and mitochondrial-mediated apoptosis.     

Nicotine promotes cell proliferation via alpha7-nicotinic acetylcholine receptor and catecholamine-synthesizing enzymes-mediated pathway in human colon adenocarcinoma HT-29 cells

Cigarette smoking has been implicated in colon cancer. Nicotine is a major alkaloid in cigarette smoke. In the present study, we showed that nicotine stimulated HT-29 cell proliferation and adrenaline production in a dose-dependent manner. The stimulatory action of nicotine was reversed by atenolol and ICI 118,551, a β₁- and β₂-selective antagonist, respectively, suggesting the role of β-adrenoceptors in mediating the action. Nicotine also significantly upregulated the expression of the catecholamine-synthesizing enzymes [tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DβH) and phenylethanolamine N-methyltransferase]. Inhibitor of TH, a rate-limiting enzyme in the catecholamine-biosynthesis pathway, reduced the actions of nicotine on cell proliferation and adrenaline production. Expression of α7-nicotinic acetylcholine receptor (α7-nAChR) was demonstrated in HT-29 cells. Methyllycaconitine, an α7-nAChR antagonist, reversed the stimulatory actions of nicotine on cell proliferation, TH and DβH expression as well as adrenaline production. Taken together, through the action on α7-nAChR nicotine stimulates HT-29 cell proliferation via the upregulation of the catecholamine-synthesis pathway and ultimately adrenaline production and β-adrenergic activation. These data reveal the contributory role α7-nAChR and β-adrenoceptors in the tumorigenesis of colon cancer cells and partly elucidate the carcinogenic action of cigarette smoke on colon cancer.     

黑木耳多糖和松多酚协同对辐射小鼠氧化损伤的修复作用

目的 研究黑木耳多糖（AAP）和松多酚（PKP）联合使用对⁶⁰Coγ辐射诱导小鼠氧化损伤的修复作用。方法 昆明小鼠除对照组外⁶⁰Coγ射线一次性全身均匀照射,总吸收剂量为4.0 Gy,吸收剂量率为1.0 Gy/min。辐射24 h后分别设AAP组、PKP组、AAP与PKP协同（AP）组及茶多酚（TP）组,分别ig 75、25、37.5+12.5、25 mg/kg（以多糖或多酚水平计）相应药物,对照组和模型组ig等体积生理盐水。连续喂养30 d后空腹24 h处死,测定小鼠的血清、脾脏、肝脏、心脏中维生素C（VC）、谷胱甘肽（GSH）、辅酶Q10（CoQ10）、丙二醛（MDA）水平和超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）活性;取小鼠无菌脾细胞进行彗星电泳,荧光显微镜成像系统采集图像。结果 辐射后给药PKP、AAP、AP和TP均可一定程度上升高VC、GSH、CoQ10水平,升高SOD、GSH-Px活性,降低MDA水平,减小脾细胞彗星尾长度,其中AP组辐射后修复效果较好。结论 与AAP、PKP、TP组比较,AP不仅可以促进体质量的恢复,还能有效地清除体内自由基,降低自由基对体内DNA造成的损伤,显著提高⁶⁰Coγ辐射诱导氧化损伤的修复能力。