[Hesperetin inhibits PM(2.5)-induced apoptosis in H9c2 cells by attenuating oxidative stress and mitochondrial damage].

Objective: To investigate the effects of hesperetin on fine particulate matter (PM(2.5)) induced apoptosis in H9c2 cells and related mechanisms. Methods: H9c2 cells were divided into 4 groups: control group (cells were cultured without intervention), PM(2.5) group (cells were treated with 800 µg/ml PM(2.5)), hesperetin group (H group, cells were treated by 40 µmol/L hesperetin for 1 h at 37 ℃), and hesperetin+PM(2.5) group (H+PM(2.5) group, cells were pretreated with hesperetin before PM(2.5) treatment). Cells were cultured for corresponding interval. Apoptotic cells were detected by Annexin Ⅴ-FITC/PI apoptosis detection kit and Hoechst staining. The intracellular reactive oxygen species (ROS) levels were measured by DCFH-DA Fluorescence Probe and mitochondrial membrane potential (MMP) was detected with JC-1 staining, respectively in these groups. Apoptotic related protein and phosphorylated MAPK expression levels were determined by Western blot. Results: (1) Flow cytometry results showed that the apoptosis rate of PM(2.5) group ((48.94±3.20)%) was significantly higher than that of control group ((8.13±1.40)%, P<0.01), which was significantly reduced in H+PM(2.5) group ((34.80±2.21)%) (P=0.003 2 vs. PM(2.5) group, P<0.01 vs. control group). The number of Hoechst 33258 positive apoptotic cells was distinctly less in H+PM(2.5) group than in PM(2.5) group. (2) The ROS levels was significantly higher in PM(2.5) group ((49.69±5.05)%) than in control group (10.57±1.33)%, P<0.01), which was significantly reduced in H+PM(2.5) group ((35.08±3.90)%) (P=0.000 2 vs. PM(2.5) group, P<0.01 vs. control group). (3) Green fluorescence indicating the JC-1 monomer form, which represented MMP loss of H9c2 cells, was significantly higher in PM(2.5) group ((20.28±4.69)%) than in control group ((10.50±2.72)%, P<0.01), which was significantly decreased in H+PM(2.5) group ((13.41±2.89)%) (P<0.01 vs. PM(2.5) group, P=0.029 4 vs. control group). (4) The expression levels of Bcl-2 protein of H9c2 cells was lower in PM(2.5) group ((76.94±4.52)%) than in control group (100%, P=0.000 9), which was significantly upregulated in H+PM(2.5) group ((92.95±6.82)%) (P=0.027 5 vs. PM(2.5) group, P=0.15 vs. control group). The expression levels of cleaved caspase-3 protein of H9c2 cells was significantly higher in PM(2).5 group ((243.98±17.94)%) than in control group (100%, P=0.000 2), which was significantly downregulated in H+PM(2.5) group ((200.45±4.31)%) (P=0.015 vs. PM(2.5) group, P<0.01 vs. control group). (5) The expression levels of phosphorylated p38 MAPK protein of H9c2 cells was higher in PM(2.5) group ((118.90±4.78)%) than in control group(100%, P=0.002 7), which could be significantly downregulated in H+PM(2.5) group ((103.30±1.27)%) (P=0.01 vs. PM(2.5) group, P=0.05 vs. control group). The expression levels of phosphorylated ERK protein of H9c2 cells was higher in PM(2.5) group ((163.50±4.98)%) than in control group (100%, P<0.01), which was significantly downregulated in H+PM(2.5) group ((139.10±2.72)%) (P=0.001 6 vs. PM(2.5) group, P<0.01 vs. control group). Conclusions: Hesperetin protects H9c2 cells from PM(2.5) stimulation through reducing oxidative stress and protecting mitochondrial function, regulating the expression of apoptotic associated proteins as well as MAPK signal pathway, thus inhibiting H9c2 cells apoptosis.

Fitness variation among host species and the paradox of ineffective rhizobia.

Legumes can preferentially select beneficial rhizobial symbionts and sanction ineffective strains that fail to fix nitrogen. Yet paradoxically, rhizobial populations vary from highly beneficial to ineffective in natural and agricultural soils. Classic models of symbiosis focus on the single dimension of symbiont cost-benefit to sympatric hosts, but fail to explain the widespread persistence of ineffective rhizobia. Here, we test a novel framework predicting that spatio-temporal and community dynamics can maintain ineffective strains in rhizobial populations. We used clonal and multistrain inoculations and quantitative culturing to investigate the relative fitness of four focal Bradyrhizobium strains varying from effective to ineffective on Acmispon strigosus. We found that an ineffective Bradyrhizobium strain can be sanctioned by its native A. strigosus host across the host's range, forming fewer and smaller nodules compared to beneficial strains. But the same ineffective Bradyrhizobium strain exhibits a nearly opposite pattern on the broadly sympatric host Acmispon wrangelianus, forming large nodules in both clonal and multistrain inoculations. These data suggest that community-level effects could favour the persistence of ineffective rhizobia and contribute to variation in symbiotic nitrogen fixation.

[Value of the endoscopic diagnosis on the lesions of the skull base in postradiotherapeutic patients with nasopharyngeal carcinoma].

Objective: To evaluate the diagnostic value of the endoscopic biopsy operation to the lesions of the skull base in the patients with nasopharyngealcarcinoma after radiotherapy. Methods: From February 2006 to February 2010, 84 patients with nasopharyngeal carcinoma suffered from the lesions of the skull base after radiotherapy were included in this study. The relationship between the pathologic results of endoscopic biopsies from the skull base and the imaging results by Magnetic Resonance Imaging(MRI) was compared and discussed. The relationship between the pathologic results and more than 2-years' follow-up was also investigated. Results: There were 71 cases with clivus, 5 cases with pterygopalatine fossa and infratemporal fossa, 4 cases with parapharyngeal space, and 4 cases with cavernous sinus. The pathologic results of endoscopic biopsies indicated that 35 cases with recurrence including 30 case with poorly differentiated squamous cell carcinomas, 5 cases with cancer nests, 49 cases with non-tumor. Chi-square test showed that there was close relationship between MRI and pathologic results (P<0.05). In the patients followed up over 2 years, the pathologic results showed 28 cases with recurrence, 48 cases with non-tumor. MRI showed 36 cases with recurrence, 40 cases with non-tumor. But during follow-up, 30 cases were proved to be recurrent and 46 cases had non-tumor. However, Chi-square test showed that there was no statistically significance between the pathological results and follow-up(P=0.62). The sensitivity, specificity and diagnostic accuracy of the endoscopic diagnosis were 90.0%, 97.8% and 95.0%. Chi-square test also showed that there was no statistically significance between MRI and follow-up (P=0.24). The sensitivity, specificity and diagnostic accuracy of MRI were 80.0%, 73.9% and 76.0%. Conclusions: The endoscopic method is a specific, sensitive, safe, effective and minimally invasive in diagnosis of lesions of the skull base in postradiotherapeutic patients with nasopharyngeal carcinoma.

[Effects of apigenin on lipopolysaccharide induced proliferation of rat aortic vascular smooth muscle cells].

Objective: To investigate the effect of natural active compounds apigenin (API) on the proliferation of rat aortic vascular smooth muscle cells (VSMCs) induced by lipopolysaccharide (LPS) and related mechanisms. Methods: VSMCs of primary cultured SD rats were obtained and the cytotoxic effects of API (0, 10, 20, 40 and 80 µmol/L) was explored by CCK-8 method. Impact of LPS (0, 0.1, 1, 10 and 100 µg/ml) on VSMCs proliferation and the impact of API (0, 10, 20, 40 µmol/L) on LPS (10 µmol)-induced VSMCs proliferation by CCK-8 methods. Using EdU and FCM method, we observed the effect of API on proliferation of VSMCs induced by LPS. VSMCs proliferation and cell cycle were also assessed by EdU method and FACS in 10 µg/ml LPS, 10 µg/ml LPS+ 40 µmol/L API and equal volume DMSO treated VSMCs. Results: (1) CCK-8 cell vitality test showed that cell vitality was not affected by 0-40 µmol/L API, while cell vitality was significantly reduced by 80 µmol/L API (57%), which was significantly lower than in blank group (P<0.05). (2) VSMCs proliferation was significantly promoted by 0.1, 1 and 10 µg/ml LPS and peaked in 10 µg/ml LPS stimulated VSMCs group, while VSMCs proliferation was significantly reduced in 100 µg/ml LPS stimulated group (P<0.05 vs. blank group). (3) LPS (10 µm/ml) induced VSMCs proliferation was not affected by 10 µmol/L API, which was significantly inhibited by 20 and 40 µmol/L API (both P<0.05 vs. LPS). (4) VSMCs proliferation assessed by EdU was significantly higher in LPS group than in blank group (P<0.01), which could be significantly reduced by cotreatment with API (P<0.01). (5) FACS results showed that percent of VSMCs in G0/G1 stage was significantly lower in LPS group compared to blank group (P<0.05), which could be significantly increased post API treatment (P<0.05 vs. LPS), while percent of VSMCs in S stage was significantly lower post API treatment in comparison with LPS group. Conclusion: API can significantly inhibit LPS-induced proliferation of VSMCs, partly through inhibiting mitosis and inducing G0/G1 cell cycle arrest.

Prolactin regulatory element-binding protein is involved in suppression of the adiponectin gene in vivo.

PURPOSE: Prolactin regulatory element-binding protein (PREB), a member of the WD-repeat protein family, has been recognized as a transcriptional factor that regulates prolactin promoter activity in the anterior pituitary of rats. PREB is expressed not only in the pituitary but also in various other tissues, including the adipose tissue. Previous studies have shown that PREB acts as a transcriptional regulator and suppresses the expression of the adiponectin gene in cultured 3T3L1 preadipocytes. The aim of this study was to further examine the potential role of PREB in adipose tissue in vivo. METHODS: Transgenic mice that overexpressing PREB (PREB transgenic mice) were generated. Insulin resistance was evaluated in PREB transgenic mice using glucose and insulin tolerance tests. Adiponectin expression in the adipose tissue was examined by western blot analysis and quantitative polymerase chain reaction (qPCR). The expression levels of stearoyl-CoA desaturase (Scd) and adiponectin receptor 2(ADIPOR2) were quantified by qPCR. RESULTS: Glucose and insulin tolerance tests revealed insulin resistance in PREB transgenic mice. Serum adiponectin and leptin concentrations were decreased. Adiponectin gene expression was decreased in the adipose tissue, which was confirmed by the downregulation of the adiponectin-dependent hepatic Scd gene and upregulation of the ADIPOR2 gene in the liver of PREB transgenic mice. We also found that pioglitazone, an agonist for the peroxisome proliferator-activated receptor-r, improved the insulin resistance in the PREB transgenic mice after a 10-day feeding period. CONCLUSIONS: These results demonstrated that PREB might contribute to the regulation of adiponectin gene expression in vivo.

Epidemic Spread of Symbiotic and Non-Symbiotic Bradyrhizobium Genotypes Across California.

The patterns and drivers of bacterial strain dominance remain poorly understood in natural populations. Here, we cultured 1292 Bradyrhizobium isolates from symbiotic root nodules and the soil root interface of the host plant Acmispon strigosus across a >840-km transect in California. To investigate epidemiology and the potential role of accessory loci as epidemic drivers, isolates were genotyped at two chromosomal loci and were assayed for presence or absence of accessory "symbiosis island" loci that encode capacity to form nodules on hosts. We found that Bradyrhizobium populations were very diverse but dominated by few haplotypes-with a single "epidemic" haplotype constituting nearly 30 % of collected isolates and spreading nearly statewide. In many Bradyrhizobium lineages, we inferred presence and absence of the symbiosis island suggesting recurrent evolutionary gain and or loss of symbiotic capacity. We did not find statistical phylogenetic evidence that the symbiosis island acquisition promotes strain dominance and both symbiotic and non-symbiotic strains exhibited population dominance and spatial spread. Our dataset reveals that a strikingly few Bradyrhizobium genotypes can rapidly spread to dominate a landscape and suggests that these epidemics are not driven by the acquisition of accessory loci as occurs in key human pathogens.