Banxia Xiexin Decoction () Treats Diabetic Gastroparesis through PLC-IP3-Ca2+/NO-cGMP-PKG Signal Pathway.

OBJECTIVE: To test the effect of Banxia Xiexin Decoction (, BXD) on the contraction and relaxation of gastric smooth muscle (SM) in diabetic gastroparesis (DGP) model rats, and to explore the mechanism of BXD in the prevention and treatment of DGP through experiments of signal pathway both in vivo and in vitro. METHODS: Sixty Sprague-Dawley rats were divided into 6 groups according to a random number table: control group, model group, high-, medium- and low-dose BXD groups (9.2, 4.6 and 1.8 g/(kg·d), respectively), and domperidone group (10 mg/(kg·d)), 10 rats per group. DGP model was established initially by a single intraperitoneal injection of streptozotocin (STZ), and was confirmed by recording gastric emptying, intestinal transport velocity and gastric myoelectric activity of rats after 2 months. Each group was treated with a corresponding drug for 4 weeks. The mRNA and protein expressions of phospholipase C (PLC), inositol triphosphate (IP3), neuronal nitric oxide synthase (nNOS), and cyclic guanosine monophosphate (cGMP) dependent protein kinase G (PKG) were detected by reverse transcription-polymerase chain reaction and Western blot, respectively, while nitric oxide (NO) and cGMP expressions were detected by enzyme-linked immunosorbent assay. Gastric tissues were obtained from rats for primary cell culture preparation. Gastric SM cells were treated with 0.8 µmol/L of STZ or STZ plus 1,000, 500 and 200 µg/mL of BXD or STZ plus 2.5 µmol/mL of domperidone for 24, 48, 72 or 96 h, respectively. The length of gastric SM cells and intracellular Ca2+ concentration ([Ca2+]i) before and after BXD treatment was measured. RESULTS: Compared with the model group, high- and medium-dose BXD and domperidone significantly increased the expressions of PLC, IP3, NO, nNOS, cGMP and PKG in rat's gastric tissue (P<0.01). Gastric SM cells treated with BXD showed a time- and dose-dependent increase in cell viability (P<0.01). The treatment with high- and medium-dose BXD and domperidone inhibited the increase in gastric SM cells length and increased [Ca2+]i compared with the model cells (P<0.01). CONCLUSIONS: Treatment with high- and medium-dose BXD significantly attenuated STZ-induced experimental DGP in rats. The therapeutic effect of BXD on DGP rats might be associated with the PLC-IP3-Ca2+/NO-cGMP-PKG signal pathway.

[Growth characteristics and control of iron bacteria on cast iron in drinking water distribution systems].

This study investigated the growth characteristics of iron bacteria on cast iron and relationship between suspended and attached iron bacteria. The steady-state growth of iron bacteria would need 12 d and iron bacteria level in effluents increased 1 lg. Hydraulics influence on iron bacteria level and detachment rate of steady-state attached iron bacteria was not significant. But it could affect the time of attached iron bacteria on cast-iron coupons reaching to steady state. When the chlorine residual was 0.3 mg/L, the iron bacteria growth could be controlled effectively and suspended and attached iron bacteria levels both decreased 1 lg. When the chlorine residual was more than 1.0 mg/L, it could not inactivate the iron bacteria of internal corrosion scale yet. There was little effect on inhibiting the iron bacteria growth that the chlorine residual was 0.05 mg/L in drinking water quality standard of China. The iron bacteria on coupons reached to steady state without disinfectant and then increased the chlorine residual to 1.25 mg/L, the attached iron bacteria level could decrease 2 lg to 3 lg. Under steady-state, the suspended iron bacteria levels were linearly dependent on the attached iron bacteria. The control of iron bacteria in drinking water distribution systems was advanced: maintaining the chlorine residual (0.3 mg/L), flushing the pipeline with high dosage disinfectant, adopting corrosion-resistant pipe materials and renovating the old pipe loop.