Protective effect and the possible mechanism of Nano-Se on myocardium of experimental diabetes mice

AIM: To observe the protective effect of Nano-Se on myocardium of experimental diabetes mice. METHODS: Sixty healthy male KM mice were chosen, ten of which were selected randomly as the normal control group. After fasted for 24 h, the rest 50 mice were injected with streptozotocin (STZ, 50 mg/kg) intraperitoneally for 5 d. At 7th d, the blood-sugar was measured from vena caudalis, 40 mice, of which blood-sugar exceeded 16.65mmol/L, were selected and randomized into 4 groups: the positive control group, low dose (25 μg/kg) Nano-Se group, mid dose (50 μg/kg) Nano-Se group, high dose (50 μg/kg) Nano-Se group. All mice were given intragastric administration of 0.2 mL normal saline and corresponding dose of Nano-Se. The body weights were measured every week, and the dose of which was adjusted according to the change of the body weights. 8 weeks later, the mice were killed and cardiac muscle of the left ventricle was taken. The myocardium was prepared to 10% homogenate for measuring SOD, GSH-Px activity and MDA content. The myocardial cell apoptosis was measured by TUNEL. The expressions of Bc1-2 and Bax proteins were determined by immunohistochemistry. RESULTS: Compared to normal group, the SOD and GSH-Px activities in positive control group decreased, MDA level increased, the rate of myocardial cell apoptosis increased significantly, Bc1-2 protein expression deceased and Bax protein expression increased. Compared to positive control group, the SOD and GSH-Px activities in low and mid dose Nano-Se groups expression increased, MDA level decreased, myocardial cell apoptosis rate decreased, Bc1-2 protein expression increased and Bax protein expression decreased. Moreover, the SOD and GSH-Px activities in high dose Nano-Se group decreased obviously compared to those in mid dose Nano-Se group. MDA level and myocardial cell apoptosis rate increased, Bc1-2 protein expression decreased and Bax protein expression increased, no significant difference in SOD, GSH- Px activity, MDA level and myocardial cell apoptosis rate was observed compared with positive control group. CONCLUSION: The damage of cardiac muscle is alleviated when a certain dose of Nano-Se is supplied to diabetes mice. The protective mechanism may be related to antioxidation, blood-sugar adjustment and the increase of Bc1-2 expressing.     

纳米硒对性成熟前雄性波尔山羊生殖机能发育的影响

 【目的】研究日粮添加纳米硒对断奶雄性山羊性成熟过程中生殖机能的影响。【方法】选用2月龄断奶、体重一致的波尔山羊公羔羊20只,随机分成2组,对照组饲喂基础日粮,处理组饲喂基础日粮+纳米硒（硒含量0.3 mg?kg-1）,预饲10 d,试验期90 d,每30 d采血分离血清测定FSH、LH和T浓度,分离睾丸测定睾丸硒浓度和GSH-Px活性,同时制作常规石蜡切片观察睾丸组织结构。试验结束时采集精液分析精液品质,分离精子,透射电镜观察精子超微结构。【结果】纳米硒可促进睾丸曲精细管和间质组织及间质细胞发育,维持曲精细管中生殖细胞的发生、分化及分裂;日粮补充纳米硒极显著增加睾丸硒沉积、提高睾丸GSH-Px活性(P＜0.01);30～60 d阶段纳米硒不影响血清生殖激素水平(P＞0.05),0～90 d阶段FSH、LH和T显著升高;纳米硒对射精量和精子密度无影响,精子活力增加10%,畸形精子数目降低27%。透射电镜观察精子超微结构,对照组精子尾部中段线粒体结构改变,排列疏松。【结论】纳米硒显著影响性成熟前公羔羊睾丸的发育,增加精子活力,降低畸形精子数,对血清生殖激素水平有一定影响。     

纳米硒对肥育猪肌肉品质的影响

以亚硒酸钠为对照,研究了纳米硒对肥育猪肌肉品质的影响.234头体重45 kg左右的杜长大肥育猪按饲养试验要求分为13组,每组3个重复,每个重复6头.将纳米硒和亚硒酸钠2种硒源分别以0.10、0.20、0.30、0.40、0.50、1.00mg/kg6个硒水平添加到基础日粮中,配制成12种试验日粮,基础日粮作对照.结果显示:①亚硒酸钠添加浓度在0～0.20 mg/kg,背最长肌滴水损失随着硒添加浓度的增加而降低;添加浓度在0.30～1.00mg/kg,滴水损失随着硒添加浓度的增加而升高;1.00 mg/kg硒添加水平滴水损失显著高于0.20～0.50 mg/kg硒添加水平(P＜0.05).纳米硒添加浓度在0.20～1.00mg/kg滴水损失始终保持在低峰平台.硒源添加浓度在0.40～1.00 mg/kg硒时,纳米硒组滴水损失显著低于亚硒酸钠组(P＜0.05).②硒源添加浓度在0.10～0.30 mg/kg时,两种硒源对背最长肌GSH-Px活性、-AOC和MDA含量的影响无显著差异(P＞0.05);硒源添加浓度在0.40～1.00mg/kg硒时,纳米硒组GSH-Px活性和T-AOC显著高于亚硒酸钠组(P＜0.05),MDA含量显著低于亚硒酸钠组(P＜0.05).③硒源添加浓度在0.10～0.30 mg/kg时,两种硒源对背最长肌硒含量的影响无显著差异;在0.40～1.00mg/kg硒添加水平上,纳米硒组背最长肌硒含量显著高于亚硒酸钠组.④空白组背最长肌肌红蛋白含量显著低于加硒组(P＜0.05),硒源和硒添加水平对背最长肌肌红蛋白没有显著影响(P＞0.05).上述结果提示,纳米硒的Weinberg剂量-效应的最适剂量范围要宽于亚硒酸钠,高剂量添加时比亚硒酸钠更能提高肌肉组织抗氧化能力,降低肉的滴水损失;肌肉硒沉积率优于亚硒酸钠.     

Dietary nano-selenium alleviated intestinal damage of juvenile grass carp(Ctenopharyngodon idella)induced by high-fat diet:Insight from intestinal morphology,tight junction,inflammation,anti-oxidization and intestinal microbiota

In recent years,high-fat diet(HFD)has been widely applied in aquaculture,which reduces the intestinal health of cultured fish.The current study evaluated the protective effects of nano-selenium(nano-Se)on intestinal health of juvenile grass carp(Ctenopharyngodon idella)fed with HFD.A total of 135 experimental fish were fed with a regular diet(Con),a HFD(HFD)and a HFD containing nano-Se at 0.6 mg/kg(HSe)for 10 weeks.The results showed that dietary nano-Se significantly improved the survival rate and feed efficiency which were reduced by HFD in juvenile grass carp(P<0.05).Also,nano-Se(0.6 mg/kg)supplement alleviated intestinal damage caused by the HFD,thus maintaining the integrity of the intestine.Moreover,it significantly up-regulated the expression of genes related to tight junction(ZO-1,claudin-3 and occludin),anti-oxidization(GPx4a and GPx4b),and the protein of ZO-1 in the intestine of juvenile grass carp,which were depressed by the HFD(P<0.05).Furthermore,nano-Se supplementation significantly suppressed the expressions of genes related to the inflammation,including inflammatory cytokines(IL-8,IL-1β,IFN-γ,TNF-αand IL-6),signaling molecules(TLR4,p38 MAPK and NF-kB p65),and protein expression of NF-kB p65 and TNF-αin the intestine of juvenile grass carp which were induced by the HFD(P<0.05).Besides,dietary nano-Se normalized the intestinal microbiota imbalance of juvenile grass carp caused by the HFD through increasing the abundance of the beneficial bacteria,e.g.,Fusobacteria.Finally,dietary nano-Se increased the production of short chain fatty acids(SCFA)in the intestine,especially for butyric acid and caproic acid,which were negatively related to the increase of intestinal permeability and inflammation.In summary,supply of nano-Se(0.6 mg/kg)in HFD could effectively alleviate intestinal injury of juvenile grass carp by improving intestinal barrier function and reducing intestinal inflammation and oxidative stress.These positive effects may be due to the regulation of nano-Se on intestinal microbiota and the subsequently increased beneficial SCFA levels.