[Berberine protects myocardial injury and cardiac dysfunction in a septic rat model].

Objectives: To investigated whether berberine could ameliorate septic cardiomyopathy in a rat model of sepsis and it's mechanisms. Methods: SD rats were divided into 3 groups: sepsis group (LPS group), rats were intraperitoneal injected of LPS (10 mg/kg); Berberine intervention group (Ber group), Ber (50 mg/kg, one time per day) was gavage fed 3 days before intraperitoneally injection of lipopolysaccharides (LPS); control group (Con group), rats were gavage fed with double distilled water (2 ml/100 g, one time per day) 3 days before intraperitoneal injection of normal saline (1 ml/100 g). LPS group and the Ber group was further divided into 3 subgroups (n=6), and the follow-up experiments were conducted at 6 h, 24 h and 48 h after LPS injection (of which 48 h subgroup rats were gavage fed with Ber/saline at 24 h). Left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), and the maximum rate of change of left ventricular pressure (±dp/dtmax) were monitored, the level of cardiac troponin T (cTnT), tumor necrosis factor (TNF)-α and interleukin (IL)-1ß was detected by ELISA method, HE staining of myocardial tissues was done to observe myocardial injury; Western blotting method was used to detect the expression of toll-like receptor 4(TLR4) protein in rat myocardial tissue, the level of myocardial cell nucleus protein p65 was detected to reflects the degree of NF-κB activation. The correlation of factors was analyzed with Pearson correlation analysis. Results: Pre-treatment with berberine stabilized cardiac hemodynamics and improved the systolic function and diastolic function in the heart of LPS-induced rats, as evidenced by the partial recovery of the reduced±dp/dtmax and LVSP, as well as the decreased LVEDP. Compared with the LPS group, the Ber group showed improved myocardial injury, as demonstrated by decreased cTnT at each time point. HE staining results showed that berberine decreased inflammatory cell infiltration and LPS-induced cell swelling. These effects were observed early at 6 hours, severe at 24 hours, and become more serious at 48 hours after LPS injection. Further, TLR4 and NF-κB p65 subunits, which were the two key factors of the TLR4/NF-κB signaling, were upregulated in the LPS group and attenuated in the Ber group. Consistently, the expression levels of the downstream cytokines TNF-α and IL-1ß were lower in the Ber group than those in the LPS group (all P<0.05). Myocardial injury markers were positively correlated with the markers of TLR4/NF-κB signals and the downstream host inflammatory factors (all P<0.05). Conclusions: Berberine can improve myocardial injury and cardiac function in sepsis rats, the mechanism is considered to be related to that it can inhibit the activation of TLR4/NF-κB signaling pathway induced by LPS and further reducing the production of TNF-α and IL-1ß.

Characterizing a novel strain of Bacillus amyloliquefaciens BAC03 for potential biological control application.

AIMS: To identify and characterize a bacterial strain BAC03, evaluate its biological control activity against potato common scab (Streptomyces spp.) and characterize an antimicrobial substance produced by BAC03. METHODS AND RESULTS: Bacterial strain BAC03, isolated from potato common scab suppressive soil, was identified as Bacillus amyloliquefaciens by analysing sequences of fragments of the recA, recN, cheA and gyrA genes. BAC03 displayed an antagonistic activity against Streptomyces spp. on agar plates using a co-culture method. In glasshouse assays, BAC03 applied in potting mix significantly reduced common scab severity (P < 0·05) and potentially increased the growth of potato plants (P < 0·05). An antimicrobial substance extracted from BAC03 by ammonium sulfate precipitation was identified as an LCI protein using liquid chromatography-mass spectrometry. The antimicrobial activity of either a BAC03 liquid culture or the ammonium sulfate precipitate fraction was stable under a wide range of temperatures, and pH levels, as well as following incubation with several chemicals, but was reduced by all proteinases tested. CONCLUSIONS: Bacillus amyloliquefaciens strain BAC03 displayed a strong antimicrobial activity, that is, the suppression of potato common scab, and may potentially enhance the plant growth. LCI protein is associated with some of the antimicrobial activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacterial strain BAC03 has the potential to be developed as a commercial biological control agent for potato common scab.