Isolation and identification of cholesterol-degrading intestinal bacteria by culturomics and evaluation of their functions / 生物工程学报

High cholesterol is one of the important factors inducing cardiovascular and cerebrovascular diseases. Drug therapy is the main method for reducing cholesterol, but has the disadvantages such as high cost and side effects. Studies have shown that intestinal bacteria play important roles in cholesterol metabolism. However, there are few reports on the screening and functional evaluation of cholesterol-lowering intestinal bacteria. In this study, 36 bile-tolerant bacteria were screened from healthy people stool through culturomics using bovine bile acid or artificial mixed bile acids as substrates. Taking Lactobacillus rhamnosus GG (LGG) as a positive control, three bile acid concentration groups (0 g/L, 0.3 g/L, 3 g/L) were set up to evaluate the cholesterol-lowering ability of bile-tolerant bacteria in vitro. Ten bacteria (including Proteus mirabilis, Providencia stuartii, Proteus vulgaris et al) were identified as the dominant cholesterol-lowering bacteria. Six of the above bacteria, Proteus mirabilis, Providencia stuartii, Proteus vulgaris, Proteus penneri, Wohlfahrtiimonas chitiniclastica, Providencia rettger, were evaluated for their ability to reduce triglycerides in vitro and tolerance to artificial gastric juice. Comparing with strain LGG, the six bacteria showed better triglyceride-lowering ability in vitro. With the decrease of pH value of artificial gastric juice and the increase of treatment time, the survival rate of six bacteria decreased. The above screening experiments and functional evaluation provide a basis for further development of potential cholesterol-lowering bacterial products.

Analysis of Iptakalim-induced gene expression changes in heart, brain and liver by cDNA microarray / 中国药理学通报

Aim To observe changes of gene expression profile in rat heart , liver and brain treated with iptakalim using cDNA microarray and analyze its molecule mechanism about pharmacology and treatment. Methods ①Rats were treated with iptakalim for 14 days at a dose of 3 mg?kg-1 by gavage. Total RNA was extracted from heart, liver and brain tissues and reversely transcribed to cDNA, which were labeled with Cy3 and Cy5 fluorescent as probes and hybridized to Gene Chip (BiostarR-40s). Scan array 3 000 was used for scanning the hybridizing signals and ImageGENE 3.0 for data analysis. Data were confirmed using RT-PCR. ②Rats were randomly divided into normal control group and 4 iptakalim groups. Iptakalim was administered orally at doses of 1, 3, 9 mg?kg-1 body weight per day for 2 weeks. The last group was orally administered at a dose of 9 mg?kg-1 body weight per day for 2 weeks, and iptakalim was withdrawn for 10 days. We observe effects of iptakalim on hemodynamics parameters in anesthetized rats and changes of myocardial structure, myofilament ultra-structure after 24h at the end of the last administration. Results ① The new chemical entity iptakalim had selectivity on changes of gene expression in rat heart, liver and brain. Compared with control group, 236 genes are changed (100 increased and 136 decreased) in rat hearts and 6 transcripts (6 increased) in rat livers, there are no changes on gene expression in rat brains. ② In anesthetized rats, iptakalim at doses of 1, 3, 9 mg?kg-1 neither affected pharmacological effects on cardiovascular hemodynamics parameters nor had pathological changes on myocardial morphological and ultrastructure. Conclusion Under the same experimental conditions, the new chemical entity iptakalim has selectivity on changes of gene expression in vital organs. Iptakalim shows no side-effects on cardiac function and tissue structure.