To investigate the the possibility to utilize the cellular fatty acid (CFA) information as a method in Brucella typing, 90 Brucella strains were subjected to the study on CFAs, and all the experimental strains were inoculated on Brucella Agar plates for 48 hours. After that, cells were harvested, saponificated, methylated and extracted to provide fatty acids methylesters for gas chromatography analysis. Based on the CFAs data matrix, dendrogram of 90 experimental strains was generated by SPSS11.5 software package. As shown in the dendrogram, 90 Brucella strains could be divided into 5 clusters. The first cluster included some species of Brucella abortus,Brucella melitensis,Brucella suis, Brucella ovis; and some of the variant strains of Brucella abortus and Brucella melitensis and the typical strain of Brucella neotomae. The second cluster included typical strains of Brucella suis (1,2,3 and 5 types); vaccine strains of Brucella suis S2; vaccine strains of Brucella melitensis M28、Rev.1 and typical strain of Brucella ovis. The third cluster included some of Brucella melitensis; some of the variant strains of Brucella melitensis; some of Brucella abortus(3,6 types); Brucella canis and Brucella ovis. The fourth cluster was the typical strain of Brucella canis.and the fifth cluster included some of Brucella melitensis(1 type); some of Brucella abortus (1 type); some of the variant strains of Brucella melitensis and Brucella suis(1,3 type). It is apparent that CFAs information can be used in brucella typing. and Brucella suis and Brucella canis can be distinguished by the difference in the CFA contents of 3 fatty acids 19:0CYCLOω8c, 18:1ω7c and 16:0. The results of CFAs typing in Brucella species show that Brucella canis includes 2 biovars at least and the high homologization of Brucella abortus (3 type) and Brucella abortus(6 type) can be found.

BACKGROUNDSteroids inhibit osteogenic differentiation and decrease bone formation while concomitantly inducing adipose deposition in osteocytes. This leads to the fatty degeneration and necrosis of bone cells commonly seen in osteonecrosis of the femoral head. The peroxisome proliferator-activated receptor-γ (PPARγ) is an adipogenic transcription factor linked to the development of this disease and responsible for inducing adipogenesis over osteogenesis in bone marrow mesenchymal stem cells (BMSCs). The aim of this study was to assess whether adipogenic differentiation could be suppressed, and thus osteogenic potential retained, by inhibiting PPARγ expression in BMSCs.

METHODSCells from the bone marrow of New Zealand rabbits were treated with 10(-7) mol/L dexamethasone and infected with one of three small interference RNA (siRNA) adenovirus vectors (S1, S2, and S3) or non-targeting control siRNA (Con) and compared with dexamethasone-treated (model) and untreated (normal) cells. Cells were grown for 21 days and stained with Sudan III for adipocyte formation. At various time points, cells were also assessed for changes in PPARγ, osteocalcin (OC), Runx2, alkaline phosphatase (ALP) activity, and triglyceride (TG) content.

RESULTSDexamethasone-treated model and control groups showed a significant increase in fatty acid-positive staining, which was inhibited in cells treated with PPARγ siRNA-treated, similar to normal untreated cells. All three siRNA groups significantly inhibited PPARγ mRNA and protein, adipocyte number, and TG content compared with the dexamethasone-treated model and control groups, matching that seen in normal cells. OC and Runx2 mRNA and protein, as well as ALP activity, were significantly higher in cells treated with siRNA against PPARγ, similar to that seen in the normal cells. These osteogenic markers were significantly lower in the dexamethasone-treated cell cultures.

CONCLUSIONSThe siRNA adenovirus vector targeting PPARγ can efficiently inhibit steroid-induced adipogenic differentiation in rabbit BMSCs and retain their osteogenic differentiation potential.

Adenoviridae ; genetics ; Adipogenesis ; drug effects ; genetics ; Animals ; Cell Differentiation ; drug effects ; genetics ; Mesenchymal Stromal Cells ; cytology ; drug effects ; metabolism ; PPAR gamma ; genetics ; metabolism ; pharmacology ; RNA, Small Interfering ; Rabbits ; Steroids