Characteristic, polymorphism and expression distribution of LCAT gene in a Mongolian gerbil model for hyperlipidemia.

This study aims to evaluate the genetic basis and activity of lecithin cholesterol acyltransferase (LCAT) in a novel Mongolian gerbil model for hyperlipidemia. Gerbils may be susceptible to high fat and cholesterol (HF/HC) diets, which can rapidly lead to the development of hyperlipidemia. Approximately 10-30% of gerbils that are over 8months old and fed controlled diets spontaneously develop hyperlipidemia. Using the HF/HC diet model, we detected triglycerides (TG), total cholesterol (TC), HDL (high density lipoprotein)-C, LDL (low density lipoprotein)-C and LCAT in both old (>8months) and young gerbils. The TC and HDL-C levels were two times higher in old gerbils compared with young gerbils (P<0.01). However, in the old group the LCAT activity fell slightly compared with the normal lipidemia group. It is reasonable to hypothesize that this may be associated with single nucleotide polymorphisms of the LCAT gene. We cloned this gene to investigate the sensitivity of the gerbil to the HF/HC diet and spontaneous hyperlipidemia. The entire LCAT gene was cloned by splicing sequences of RACE (rapid amplification of cDNA ends) and nest-PCR products (AN: KC533867.1). The results showed that the 3683base pair gene consists of six exons and five introns. The LCAT protein consists of 444 amino acid (AA) residues, which are analogous to the human LCAT gene, and includes 24 signal peptide AA and 420 mature protein AA. Expression of LCAT was detected in the kidney, spleen and adrenal tissue, apart from the liver, by immunohistochemistry. The abundance of the protein was greater in the older group compared with the control group. Polymorphisms were analyzed by PCR-SSCP (PCR-single-strand conformation polymorphism) but none were found in 444 animals of the ZCLA closed population (a Chinese cultured laboratory gerbil population).

Hypolipidemic and antioxidant activities of polysaccharides from Rosae Laevigatae Fructus in rats.

Two major fractions (RLP-1 and RLP-2) were obtained by purifying the crude polysaccharides extracted from a traditional Chinese herb Rosae Laevigatae Fructus. The average molecular weight of RLP-1 and RLP-2 was 21.5 kDa and 16.1 kDa, respectively. Monosaccharide analysis indicated that RLP-1 was composed of xylose, mannose and galactose in the molar ratio of 1:11:8, while RLP-2 was only a glucan. Oral administration of RLP-1 could significantly decrease levels of serum total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), inhibit hepatic lipid accumulation, increase antioxidant lipids and up-regulate expressions of peroxisome proliferator-activated receptor-γ (PPAR-γ) and lipoprotein lipase (LPL) in hyperlipidemia rats. These results suggest that RLP-1 improve hyperlipidemia possibly through regulating PPAR-mediated lipid metabolism. Therefore, could be explored as a possible agent for hyperlipidemia.

Dietary quercetin ameliorates nonalcoholic steatohepatitis induced by a high-fat diet in gerbils.

Dietary quercetin is highly abundant in edible plants, which possesses a wide range of pharmacological properties. This study was to investigate hepatoprotective effects of quercetin in the nonalcoholic steatohepatitis (NASH) gerbils induced by a high-fat diet (HFD), and to evaluate its regulatory mechanism on hepatic inflammatory response. The gerbils were fed with HFD for 28 days to induce NASH. From 15th day to 28th day, the treated drugs were given daily to each animal, respectively. The lipid profiles and biochemical markers were determined at the end of the experiment. The expressions of Sirt1, NF-κB p65 and iNOS were detected by immunohistochemistry and Western blot analysis. The results showed that oral administration of quercetin at doses of 30-60 mg/kg to hyperlipidemia rats for 14 days were highly effective in decreasing the levels of serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), alanine aminotransferase (ALT) and aspartate aminotransferase (AST). It could decrease lipid accumulation in the hepatocytes, and reduce serum levels of pro-inflammatory cytokines TNF-α and IL-6 via regulating the expressions of Sirt1, NF-κB p65 and iNOS. Thus, dietary quercetin had significant therapeutic benefits and could be explored as a potential promising candidate for the prevention of NASH.

[Molecular genetic evolution analysis of new A(H1N1) influenza virus].

In order to analyze the molecular epidemiology of A (H1N1) influenza virus in 2009, the complete genome sequences of influenza strains from different host sources downloaded from the NCBI were analyzed on genetic evolution by DNAstar software in this research. The results showed that 79 mutation sites of new A (H1N1) influenza virus were observed compared to previous human A (H1N1) influenza strain, including 14 mutation sites new in all A (H1N1) influenza sources and 37 mutation sites only observed in swine strain. A significant difference was represented in antigenic sites between new A (H1N1) influenza strain and the previous human A (H1N1) strain. This phenomenon shows the new A (H1N1) influenza strain is either originated from the recombination of human and swine strain or from the infection in pig populations and gradual mutation to human tansmission, which remains to be further studied.