[Effect of Erchen Decoction on liver mitochondrial function by inhibiting mTORC1/SREBP1/CAV1 pathway in mice with high-fat diet].

This study aims to investigate the effect of Erchen Decoction(ECD) on liver mitochondrial function in mice with a high-fat diet and its possible mechanism. A total of sixty C57BL/6J mice were randomly divided into a normal group, high-fat group, ECD group, mTORC1 activator(MHY) group, ECD+MHY group, and polyene phosphatidyl choline(PPC) group, with 10 rats in each group. The normal group was given a normal diet, and the other groups were fed a high-fat diet for 20 weeks. At the 17th week, the ECD group and ECD+MHY group were given ECD(8.7 g·kg~(-1)) daily, and the PPC group was given PPC(0.18 g·kg~(-1)) daily, while the remaining groups were given normal saline(0.01 mL·g~(-1)) daily for four weeks. In the 19th week, the MHY group and ECD+MHY group were injected intraperitoneally with MHY(5 mg·kg~(-1)) every other day for two weeks. During the experiment, the general conditions of the mice were observed. The contents of triglyceride(TG) and total cholesterol(TC) in serum were measured. Morphological changes in liver tissue were examined through HE and oil red O staining. The content of adenosine triphosphate(ATP) was determined using chemiluminescence, and mitochondrial membrane potential was assessed using a fluorescence probe(JC-1). Western blot was performed to detect the expression of rapamycin target protein complex 1(mTOR1), ribosomal protein S6 kinase B1(S6K), sterol regulatory element binding protein 1(SREBP1), and caveolin 1(CAV1). RESULTS:: revealed that compared with the normal group, the mice in the high-fat group exhibited significant increases in body weight and abdominal circumference(P<0.01). Additionally, there were significant increases in TG and TC levels(P<0.01). HE and oil red O staining showed that the boundaries of hepatic lobules were unclear; hepatocytes were enlarged, round, and irregularly arranged, with obvious lipid droplet deposition and inflammatory cell infiltration. The liver ATP content and mitochondrial membrane potential decreased significantly(P<0.01). The expression of p-mTOR, p-S6K, and n-SREBP1 increased significantly(P<0.01), while the expression of CAV1 decreased significantly(P<0.01). Compared with the high-fat group, the body weight and TG content of mice in the ECD group and PPC group decreased significantly(P<0.05). Improvements were observed in hepatocyte morphology, lipid deposition, and inflammatory cell infiltration. Furthermore, there were significant increases in ATP content and mitochondrial membrane potential(P<0.05 or P<0.01). The expression of p-mTOR, p-S6K, and n-SREBP1 decreased significantly in the ECD group(P<0.01), while CAV1 expression increased significantly(P<0.01). However, the indices mentioned above did not show improvement in the MHY group. When the ECD+MHY group was compared with the MHY group, there were significant reductions in body weight and TG contents(P<0.05). The morphological changes of hepatocytes, lipid deposition, and inflammatory cell infiltration were recovered. Moreover, there were significant increases in liver ATP content and mitochondrial membrane potential(P<0.05 or P<0.05). The expression of p-mTOR, p-S6K, and n-SREBP1 decreased significantly(P<0.01), while CAV1 expression increased significantly(P<0.01). In conclusion, ECD can improve mitochondrial function by regulating the mTORC1/SREBP1/CAV1 pathway. This mechanism may be involved in the resolution of phlegm syndrome and the regulation of lipid metabolism.

[Synergistic antibacterial effect and mechanisms of dihydroartemisinin and cefuroxime incombination].

In this study, we explored the antibacterial effect and mechanism of dihydroartemisinin(DHA) combined with cefuroxime(CFX) or ampicillin against Escherichia coli. The minimum inhibitory concentration(MIC) of DHA, cefuroxime, and ampicillin against E. coli was 300,25,25 µmol·L~(-1), respectively, determined by broth microdilution method and 2,3,5-triphenyltetrazolium chloride(TTC) method. The minimum bactericidal concentration(MBC) was 25 µmol·L~(-1) for cefuroxime, above 600 µmol·L~(-1) for DHA. The fractional inhibitory concentration index(FICI) of DHA combined with cefuroxime or ampicillin was 0.375 and 0.75, respectively, determined by checkerboard microdilution assay, suggesting the synergistic effect or additive effect of the drug combination. Moreover, the time-effect curve showed that the antibacterial activity of DHA and CFX combination was much stronger than that of either of the drugs, suggesting that combination with DHA can decrease the CFX dosage. Then we studied the synergistic mechanism of DHA combined with cefuroxime and found that the combination of the two drugs had a significant inhibitory effect on the total protein bands, as shown by the results of polypropylene gel electrophoresis. The results of conductivity method and alkaline phosphatase test respectively showed that its conductivity value and alkaline phosphatase(AKP) leak were significantly higher than either of the drugs, suggesting that the integrity of bacteria may be damaged. The scanning electron microscope(SEM) results showed that the morphology of E. coli was destroyed most in the combination group. The quantitative fluorescence PCR technology showed that the combination of two drugs can inhibit the expression of superoxide stress gene soxS. In summary, the combination of dihydroartemisinin and cefuroxime has a synergistic antibacterial effect on E. coli.

Effects of monosulfuron-ester on metabolic processes of nitrogen-fixing cyanobacteria Anabaena flos-aquae and Anabaena azotica

Abstract Presence of the relatively new sulfonylurea herbicide monosulfuron-ester at 0.03-300 nmol/L affected the growth of two non-target nitrogen-fixing cyanobacteria (Anabaena flos-aquae and Anabaena azotica) and substantially inhibited in vitro Acetolactate synthase activity, with IC50 of 3.3 and 101.3 nmol/L for A. flos-aquae and A. azotica, respectively. Presenting in 30-300 nmol/L, it inhibited protein synthesis of the cyanobacteria with less amino acids produced as its concentration increased. Our findings support the view that monosulfuron-ester toxicity in both nitrogen-fixing cyanobacteria is due to its interference with protein metabolism via inhibition of branch-chain amino acid biosynthesis, and particularly Acetolactate synthase activity.

Overexpression of Tau Rescues Nogo-66-Induced Neurite Outgrowth Inhibition In Vitro.

Nogo-66 plays a central role in the myelin-mediated inhibition of neurite outgrowth. Tau is a microtubule-associated protein involved in microtubule assembly and stabilization. It remains unverified whether tau interacts directly with growth factor receptors, or engages in cross-talk with regeneration inhibitors like Nogo-66. Here, we report that plasmid overexpression of tau significantly elevated the protein levels of total tau, phosphorylated tau, and microtubule-affinity regulating kinase (MARK). Nogo-66 transiently elevated the total tau protein level and persistently reduced the level of p-S262 tau (tau phosphorylated at serine 262), whereas it had little influence on the level of p-T205 tau (tau phosphorylated at threonine 205). Nogo-66 significantly decreased the protein level of MARK. Hymenialdisine, an inhibitor of MARK, significantly reduced the level of p-S262 tau. Overexpression of tau rescued the Nogo-66-induced inhibition of neurite outgrowth in neuroblastoma 2a (N2a) cells and primary cortical neurons. However, concomitant inhibition of MARK abolished the rescue of neurite outgrowth by tau in N2a cells. We conclude that dephosphorylation of tau at S262 is able to regulate Nogo-66 signaling, and that overexpression of tau can rescue the Nogo-66-induced inhibition of neurite outgrowth in vitro.

GSK-3ß activation mediates Nogo-66-induced inhibition of neurite outgrowth in N2a cells.

The axons of the adult mammalian brain and spinal cord fail to regenerate after injury, and it has been suggested that Nogo-66 could prevent CNS axon repair. However, the mechanism of Nogo-66 inhibiting neurite outgrowth remains unknown. Our previous results indicated that protein kinase B (PKB) is involved in the inhibition of the neurite outgrowth by Nogo-66. Glycogen synthase kinase-3ß (GSK-3ß) is implicated in many processes in the nervous system, including differentiation, specification, polarity, plasticity and axon growth. In addition, GSK-3ß is one of the most important molecules downstream of PKB. In the present study, we report on the role of GSK-3ß signaling on Nogo-66-treated mouse neuroblastoma N2a cells. Nogo-66 reduced the phosphorylation of GSK-3ß at Ser9 in N2a cells. In contrast, pretreatment with SB216763, a specific inhibitor of GSK-3ß, resulted in an amelioration of neurite outgrowth by Nogo-66, compared with the Nogo-66 alone group (P<0.05). Moreover, we performed RNA interference experiments to knock down GSK-3ß expression levels in N2a cells via transient transfection of shRNA plasmids. The inhibition of neurite outgrowth by Nogo-66 was subdued in shRNA cells, compared to the non-RNAi cells (P<0.05). Taken together, these data suggest that GSK-3ß is involved in the inhibition by Nogo-66 of neurite outgrowth in N2a cells.

[Effects of tobacco on rat gingival fibroblats attaching to titanium].

PURPOSE: The study was designed to observe the effects of the smokeless tobacco extract(ST) on the attachment,morphology,structure and proliferation of rat gingival fibroblasts(RGFs) to titanium in vitro. METHODS: RGFs were obtained from explants of rat normal gingival tissues by using tissue-explant technique.The origin of cells was identified by immunochemistry of vimentin and cytokeratin. RGFs to titanium were cultured in the presence of ST at various concentration,the attachment and growth of cells attached to titanium were measured by MTT method, immunofluorescence was used to detect and analyze the shapes of RGFs attached to titanium.Statistical analysis was performed using SPSS13.0 software package for one-way ANOVA. RESULTS: Immunochemical study showed that vimentin was expressed in RGFs while cytokeratin was negative,which indicated that RGFs were originated from mesoblastoma.With the increasing of ST concentration,the attachment,spreading shape and proliferation of RGFs in all groups decreased in a concentration-dependent manner.The difference between ST group and control group was statistically significant(P<0.05). CONCLUSIONS: ST can inhibit the attachment,spreading shape and proliferation of RGFs, suggesting that smoking may have influence on the long result of oral implant operation.