Chitooligosaccharides protect cultured hippocampal neurons against glutamate-induced neurotoxicity

Chitooligosaccharides (COSs), the biodegradation product of chitosan, have demonstrated a diverse array of biological activities. Here we report the protective effect of COSs (M.W. 800) against glutamate-induced neurotoxicity in cultured hippocampal neurons. The cell viability assessments, together with Hoechst 33342 staining and flow cytometry for cell apoptosis analysis, indicated that glutamate (125 μM)-induced cell apoptosis in cultured hippocampal neurons was attenuated in a concentration-dependent manner by COSs pretreatment. After measurement with Fluo 4-AM, COSs were found to depress glutamate-induced elevation in intracellular calcium concentration ([Ca²⁺]_c). The enzymatic assay indicated that COSs antagonized glutamate-evoked activation of caspase-3. These results collectively suggest that COSs prevent cultured hippocampal neurons from glutamate-induced cell damage by interfering with an increase in [Ca²⁺]_c and inhibiting caspase-3 activity.     

Antidiabetic effects of chitooligosaccharides on pancreatic islet cells in streptozotocin-induced diabetic rats

AIM： To investigate the effect of chitooligosaccharides on proliferation of pancreatic islet cells, release of insulin and 2 h plasma glucose in streptozotocin-induced diabetic rats. METHODS： In vitro, the effect of chitooligosaccharides on proliferation of pancreatic islet cells and release of insulin was detected with optical microscopy, colorimetric assay, and radioimmunoassay respectively. In vivo, the general clinical symptoms, 2 h plasma glucose, urine glucose, oral glucose tolerance were examined after sixty days of feeding study to determine the effect of chitooligosaccharides in streptozotocin-induced diabetic rats. RESULTS： Chitooligosaccharides could effectively accelerate the proliferation of pancreatic islet cells. Chitooligosaccharides （100 mg/L） had direct and prominent effect on pancreastic β cells and insulin release from islet cells. All concentrations of chitooligosaccharides could improve the general clinical symptoms of diabetic rats, decrease the 2 h plasma glucose and urine glucose, and normalize the disorders of glucose tolerance. CONCLUSION： Chitooligosaccharides possess various biological activities and can be used in the treatment of diabetes mellitus.     

Inhibitory effects of chitooligosaccharides on tumor growth and metastasis

Chitooligosaccharides (COS) are hydrolyzed products of chitosan and have been proven to exhibit various biological functions. The objectives of this study were to evaluate the anti-tumor growth, anti-metastatic potency and related pathways of COS extracted from fungi. In in vitro studies, we found that COS significantly inhibited human hepatocellular carcinoma (HepG2) cell proliferation, reduced the percentage of S-phase and decreased DNA synthesis rate in COS-treated HepG2 cells. Expressions of cell cycle-related genes were analyzed and the results indicated that p21 was up-regulated, while PCNA, cyclin A and cdk-2 were down-regulated. Moreover, we also found that the activity of metastatic related protein (MMP-9) could be inhibited by COS in Lewis lung carcinoma (LLC) cells. In in vivo studies, we found that COS inhibited the tumor growth of HepG2 xenografts in severe combined immune deficient (SCID) mice. In a LLC-bearing mouse tumor growth and lung metastasis model, COS inhibited tumor growth and the number of lung colonies in LLC-bearing mice as well as the lung metastasis, and it prolonged the survival time of the LLC-mice. These results suggest a potential anti-tumor growth and anti-metastatic potency of COS in cancer chemoprevention.     

唾液及壳寡糖对变形链菌生物膜黏附和脱落的影响

目的:观察唾液及壳寡糖对变形链球菌生物膜脱落的影响.方法:在盖玻片上形成24 h变形链球菌生物膜,分别加入浓度依次为2.5、5、10、20、40 g/L、相对分子量为2 000的壳寡糖溶液,作用30 min,然后应用死菌/活菌荧光染色和激光共聚焦扫描显微镜技术相结合,比较壳寡糖促进变链茵生物膜脱落的效果,对所得数据进行...     

甲壳低聚糖对抗生素脱污染小鼠肠道菌群的影响

目的观察甲壳低聚糖对抗生素脱污染小鼠肠道菌群的影响,为进一步开发壳聚糖提供理论依据.方法用盐酸林可霉素复制肠道脱污染小鼠动物模型,将模型小鼠随机分为治疗组和对照组,治疗组灌服甲壳低聚糖600mg@kg-1@d-1,对照组灌服等体积蒸馏水.7天后分析肠道菌群.结果模型小鼠治疗组肠道菌群基本恢复正常,与对照组相比差异具有显著性意义(P＜0.05).结论甲壳低聚糖对小鼠肠道菌群失调具有一定的调整作用.     

The promotion of peripheral nerve regeneration by chitooligosaccharides in the rat nerve crush injury model

Chitooligosaccharides (COSs), the biodegradation product of chitosan, have shown many biological functions. In this study, we examined the possible benefits of treatment with COSs (M.W. 800) on regeneration of rat crushed sciatic nerves. The rats with sciatic nerve crush injury were administered intraperitoneally daily with 3 or 6 mg/kg body weight of COSs over a 3-week period. During and at the end of COSs treatment, a series of functional and histological examinations, including the measurement of withdrawal reflex latency (WRL) values, walking track analysis, electrophysiological assessments, morphometric analysis of gastrocnemius muscle, as well as immunohistochemistry and electromicroscopy to regenerated sciatic nerves, were performed to evaluate the therapeutic outcomes of COSs. The experimental data demonstrated that COSs promoted peripheral nerve regeneration with the desired functional recovery in the rat sciatic nerve crush injury model. This study raises a possibility of developing COSs as a potential neuroprotective agent for peripheral nerve repair applications.     

甲壳低聚糖对糖尿病小鼠血糖和肠道菌群的影响

目的观察甲壳低聚糖对链脲佐菌素 (STZ)糖尿病小鼠血糖和肠道菌群的影响。方法将用STZ诱导的糖尿病模型小鼠分为糖尿病治疗组和糖尿病对照组 ,分别灌胃甲壳低聚糖 60 0mg (kg·d)和等体积的蒸馏水 ,连续 2 1d ,而后检测两组小鼠血糖及肠道菌群的变化。结果糖尿病治疗组小鼠的血糖降低、肠道菌群中双歧杆菌数量增多 ,与糖尿病对照组比较差异有显著性 (P <0 .0 5 )。结论甲壳低聚糖具有降低STZ糖尿病小鼠血糖及调节肠道菌群功能     

甲壳低聚糖对NOD鼠糖尿病的预防作用

目的 :探讨甲壳低聚糖对NOD鼠糖尿病的预防作用机制。方法 :将 5周龄未发病的NOD小鼠分为糖尿病预防组和对照组。预防组用 3 %甲壳低聚糖溶液作饮用水 ,对照组用冷开水作饮用水 ,连续 15周 ,定期测血糖 ,称体重 ,实验末计算糖尿病的发病率 ,HE染色观察胰岛炎。结果 :对照组 12周龄即出现高血糖 ,而预防组至实验结束仅有少数出现高血糖 ,两组相比具有显著差异性 (P <0 0 1)。NOD鼠预防组糖尿病发病率 (2 5% )低于对照组 (79% ) (P <0 0 5) ,同时减轻胰岛炎的严重程度 (P <0 0 5)。结论 :甲壳低聚糖对NOD鼠糖尿病的确有预防作用 ,其机制可能与甲壳低聚糖的非特异性免疫调节作用 ,及抗氧化等有关。     

Chitooligosaccharides promote radiosensitivity in colon cancer line SW480

AIM: To investigate the anti-proliferation and radiosensitization effect of chitooligosaccharides(COS) on human colon cancer cell line SW480.METHODS: SW480 cells were treated with 0, 1.0, 2.0, 3.0, 4.0 and 5.0 mg/m L of COS for 48 h. CCK-8 assay was employed to obtain the cell survival ratio of SW480 cells, and the anti-proliferation curve was observed with the inhibition ratio of COS on SW480 cells. The RAY + COS group was treated with 1.0 mg/m L of COS for 48 h, while both the RAY and RAY+COS groups were exposed to X-ray at 0, 1, 2, 4, 6 and 8 Gy, respectively. Clonogenic assay was used to analyze cell viability in the two groups at 10 d after treatment, and a cell survival curve was used to analyze the sensitization ratio of COS. The RAY group was exposed to X-ray at 6 Gy, while the RAY+COS group was treated with 1.0 mg/m L of COS for 48 h in advance and exposed to X-ray at 6 Gy. Flow cytometry was employed to detect cell cycle and apoptosis rate in the non-treatment group, as well as in the RAY and RAY + COS groups after 24 h of treatment.RESULTS: COS inhibited the proliferation of SW480 cells, and the inhibition rate positively correlated with the concentration of COS(P 0.01). Cell viability decreased as radiation dose increased in the RAY and RAY+COS groups(P 0.01). Cell viabilities in the RAY+COS group were lower than in the RAY group at all doses of X-ray exposure(P 0.01), and the sensitization ratio of COS on SW480 cells was 1.39. Compared with the non-treatment group, there was a significant increase in apoptosis rate in both the RAYand RAY + COS groups; while the apoptosis rate in the RAY+COS group was significantly higher than in the RAY group(P 0.01). In comparing these three groups, the percentage of G2/M phase in both the RAY and RAY + COS groups significantly increased, and the percentage of the S phase and G0/G1 phase was downregulated. Furthermore, the percentage in the G2/M phase was higher, and the percentage in the S phase and G0/G1 phase was lower in the RAY + COS group vs RAY group(P 0.01). CONCLUSION: COS can inhibit the proliferation of SW480 cells and enhance the radiosensitization of SW480 cells, inducing apoptosis and G2/M phase arrest.     

壳寡糖及其衍生物对糖尿病大鼠糖耐量及肠道微生态平衡的影响

目的:研究不同剂量的壳寡糖和N-乙酰氨基单糖对STZ诱导的糖尿病大鼠的糖耐量作用及肠道微生态平衡的影响.方法:按65 mg/kg体质量一次性ip STZ制备糖尿病大鼠模型.大鼠随机分为9组:正常对照组,二甲双胍阳性对照组,阴性对照组,壳寡糖高、中、低剂量组,N-乙酰氨基单糖高、中、低剂量组.正常对照组、阴性对照组每天灌胃蒸馏水(10 mL/kg);二甲双胍阳性对照组每天200 mg/kg灌胃;壳寡糖、N-乙酰氨基单糖组分别按250,500,1500 mg/kg每天灌胃,连续60 d,然后观察各组大鼠的一般状况和饮食.按2.5 g/kg体质量葡萄糖水溶液灌胃(ig),测定各组大鼠0,0.5,1,2h耐糖血糖值,并分别对各组大鼠肠道菌群进行培养,计数并计算B/E值.结果:不同剂量的壳寡糖和N-乙酰氨基单糖均能不同程度改善糖尿病大鼠的体质量减轻、多饮、多食等症状,中、高剂量组的效果要优于低剂量组.各模型组的葡萄糖糖耐量均有不同程度受损.壳寡糖各组葡萄糖耐量的显著改善(P<0.01),中剂量组效果最好;N-乙酰氨基单糖低剂量和中剂量显著改善葡萄糖耐量(P<0.05),低剂量组的效果最好.糖尿病大鼠肠道内大肠肝茵和肠球菌数量升高,而乳酸杆菌和双歧杆菌的数量明显下降.壳寡糖各剂量组可明显降低大肠肝茵和肠球菌的数量(P<0.01),对双歧杆菌和乳酸杆菌的增殖作用也有显著作用(P<0.01),且改善效果随着剂量的增加而增加;N-乙酰氨基单糖各剂量组随着剂量的增加使大肠杆菌和肠球菌的数量降低,高剂量组乳酸杆菌的增殖作用显著提高(P<0.01).单纯糖尿病大鼠组需氧菌总数量升高,而厌氧菌总数量升高明显下降,厌氧菌与需氧茵之比及B/E值<1.壳寡糖各剂量组均可使B/E值显著升高(P<0.01);N-乙酰氨基单糖高剂量组厌氧茵总数显著改善(P<0.05).结论:不同剂量的壳寡糖和N-乙酰氨基单糖均能不同程度的改善糖尿病大鼠的体质量减轻、多饮、多食等症状,改善葡萄糖耐量,对肠道微生态有调节作用.