[Effect of electroacupuncture at "Zusanli" (ST36) and "Tianshu" (ST25) on intestinal function and autonomic nerve balance in rats with irritable bowel syndrome].

OBJECTIVE: To study whether electroacupuncture (EA) of "Zusanli" (ST36) combined with "Tianshu" (ST25) has a synergistic effect in regulating the colonic function and autonomic nerve balance in rats with irritable bowel syndrome (IBS). METHODS: Male Wistar rats were randomly divided into control, model, EA-ST36, and EA-ST36+ST25 groups, with 14 rats in each group. The IBS model was established by using water avoidance stress method. The visceral hypersensitivity was measured using the abdominal wall retraction reflex (AWR). The rectus abdominis electromyogram (EMG), intestinal electrical activity, and electrocardiogram (ECG) were recorded using a PowerLab data acquisition and analysis system. The contents of serum cAMP and cGMP were determined by ELISA, the expression levels of colonic tyrosine hydroxylase (TH) and choline acetyl-transferase (ChAT) proteins were determined by immunofluorescence staining and Western blot, respectively. RESULTS: Compared with the control group, the model group had an evident increase in the levels of AWR, LF, LF/HF, ChAT protein expression, cAMP and cGMP contents and cAMP/cGMP ratio (P<0.001, P<0.05), and a marked decrease in the levels of HF, frequency of slow waves of intestinal EMG, visceral pain threshold (PT), immunoactivity and expression of TH protein (P<0.05, P<0.001). In contrast to the model group, the levels of AWR, LF, LF/HF, ChAT protein expression and immunoactivity, cAMP and cGMP contents and ratio of cAMP/cGMP were significantly reduced (P<0.001, P<0.05, P<0.01), whereas the levels of frequency of slow waves of intestinal EMG, PT, and the immunoactivity and expression of TH were considerably increased (P<0.001, P<0.05) in both EA-ST36 and EA-ST36+ST25 groups. CONCLUSION: EA of both ST36 and ST36+ST25 can relieve visceral pain, and reduce sympathetic activity to improve autonomic nerve balance, but without apparent synergistic effect between EA-ST36 and EA-ST25 in rats with IBS.

Autophagy in Gastric Mucosa: The Dual Role and Potential Therapeutic Target.

The incidence of stomach diseases is very high, which has a significant impact on human health. Damaged gastric mucosa is more vulnerable to injury, leading to bleeding and perforation, which eventually aggravates the primary disease. Therefore, the protection of gastric mucosa is crucial. However, existing drugs that protect gastric mucosa can cause nonnegligible side effects, such as hepatic inflammation, nephritis, hypoacidity, impotence, osteoporotic bone fracture, and hypergastrinemia. Autophagy, as a major intracellular lysosome-dependent degradation process, plays a key role in maintaining intracellular homeostasis and resisting environmental pressure, which may be a potential therapeutic target for protecting gastric mucosa. Recent studies have demonstrated that autophagy played a dual role when gastric mucosa exposed to biological and chemical factors. More indepth studies are needed on the protective effect of autophagy in gastric mucosa. In this review, we focus on the mechanisms and the dual role of various biological and chemical factors regulating autophagy, such as Helicobacter pylori, virus, and nonsteroidal anti-inflammatory drugs. And we summarize the pathophysiological properties and pharmacological strategies for the protection of gastric mucosa through autophagy.

Retinoic Acid Synthesis Deficiency Fosters the Generation of Polymorphonuclear Myeloid-Derived Suppressor Cells in Colorectal Cancer.

Metabolism is reprogrammed in cancer to fulfill the demands of malignant cells for cancer initiation and progression. Apart from its effects within cancer cells, little is known about whether and how reprogramed metabolism regulates the surrounding tumor microenvironment (TME). Myeloid-derived suppressor cells (MDSC) are key regulators of the TME and greatly affect tumor progression and therapeutic responses. In this study, our results revealed that retinol metabolism-related genes and enzymes were significantly downregulated in human colorectal cancer compared with adjacent colonic tissues, and tumors exhibited a defect in retinoic acid (RA) synthesis. Reduced ADH1-mediated retinol metabolism was associated with attenuated RA signaling and accumulated MDSCs in colorectal cancer tumors. Using an in vitro model, generating MDSCs from CD34+ myeloid precursors, we found that exogenous RA could abrogate the generation of polymorphonuclear MDSCs (PMN-MDSC) with negligible impact on myeloid differentiation. Mechanistically, RA could restrain the glycolytic capacity of myeloid cells, which in turn activated the AMP-activated protein kinase (AMPK) pathway, further impairing the suppressive capacity of myeloid cells. Supplementation with RA could significantly delay tumor growth, with reduced arginase-1-expressing myeloid cells and increased CD8+ and granzyme B+ T cells in both colitis-associated and implanted MC38 mouse colorectal cancer models. Our results indicated that the defect in ADH1-mediated RA synthesis could provide a possible mechanism that fosters the generation of PMN-MDSCs in colorectal cancer and that restoring RA signaling in the TME could serve as a promising therapeutic strategy to abrogate the generation of PMN-MDSCs.

[Inhibitory Effect of Phenol on Phosphorus Removal Performance of an EBPR System].

An SBR reactor was operated to study the inhibitory effect of different concentrations of phenol (5, 10, 30, 50, 100, 150, and 200 mg·L-1) on the phosphorus removal performance of an EBPR system. The results showed that when the phenol concentration was no higher than 50 mg·L-1, the removal efficiencies of COD and PO43--P were above 85%. The system showed efficient pollutant removal performance. However, when phenol was higher than 100 mg·L-1, phosphorus removal performance of the reactor decreased drastically. When phenol concentration was 200 mg·L-1, the system lost phosphorus removal performance after only 22 cycles. The average COD removal efficiency dropped to 61.3%, and high removal performance recovery was not observed in the short term. Meanwhile, it was found that long-term dosing of phenol inhibited phosphorus removal of the sludge subjected to EBPR. Furthermore, the inhibition on aerobic phosphate uptake was greater than that on anaerobic phosphate release. In addition, the limited sludge bulking disappeared gradually owing to acclimation of the sludge to toxicity with a low phenol concentration (≤ 50 mg·L-1). However, high concentration of phenol induced sludge bulking was difficult to recover. The short-term impact experiments showed that effluent COD and phosphorus fluctuation caused by phenol could be recovered gradually by removing phenol, suggesting that the inhibitory effect of phenol on phosphorus removal was reversible.

[Phosphorus Removal Capacity of Domestic Wastewater Treated by a Modified CAST Process Under Different Operating Modes].

A modified cyclic activated sludge technology (CAST) treating domestic wastewater was employed to investigate the effects of different operating modes, such as C/P ratio, reflux ratio, and temperature on phosphorus removal. The results illustrated that at room temperature the phosphorus removal of the system improved significantly when the influent C/P ratio increased from 50 to 100, with the removal efficiency increasing rapidly from 15% to 95.6%. Decreasing the C/P ratio to 75, the phosphorus removal performance declined due to influent carbon source deficiency, and the mean phosphorous removal efficiency decreased to 51.4%. At the same time, the long-term addition of an easily degradable carbon source resulted in sludge bulking and a large amount of sludge loss. With a low C/P ratio, the phosphorus removal performance increased by 2.3 times when the sludge reflux ratio decreased from 25% to 12.5%. However, the phosphorus removal performance declined when reducing it to 0. The temperature experiment results showed that the phosphorous removal efficiency of the system remained stable, above 90%, in the low temperature system (14℃±1℃). However, the phosphorous removal efficiency of a shortcut nitrification system at high temperature (27℃±1℃) was only 14.1%, suggesting that a low temperature was beneficial for removing phosphorous. It was observed from the batch tests that the sludge at room temperature could utilize dissolved oxygen, nitrate, and nitrite as electron acceptors to take up phosphate. The sludge in the low temperature system could use both dissolved oxygen and nitrate as the electron acceptors. However, the sludge in the high temperature system could only use dissolved oxygen as the electron acceptors to take up phosphate. In addition, it was also found that sludge under starvation conditions resulting from short-term idling of the system favored phosphorus removal.

[Effects of Side-stream Phosphorus Recovery on the Performance of EBPR System Under Low Dissolved Oxygen Condition].

A sequencing batch reactor (SBR) was operated with alternating anaerobic/oxic (An/O) condition to investigate the nitrogen and phosphorus removal performance of EBPR with DO=1 mg·L-1 and the phosphorus recovery effect at extracting side stream ratio of 0, 1/4, 1/3, 1/2 anaerobic phosphorus supernatant. The removal efficiency of NH4+-N was found to be relatively stable during all experimental stages but effluent COD of the system during later period remained as high as 81.3 mg·L-1. In the absence of side stream, the average phosphorus removal efficiency was 89.4% and increased to 98.5% and 99.0% when the side stream ratio was 1/4 and 1/3, respectively. However, the phosphorus removal performance began to fluctuate with side stream ratio of 1/2 and the lowest phosphorus removal rate was 65.4%. During each experimental stage, only one day effluent TP failed to meet the national wastewater discharge standard A with side stream ratio of 1/3 in the initial period. Besides, 93.3% of effluent TP which could meet the national standard with side stream ratio of 1/3 was far better than 45.5% of that with side stream ratio of 1/2. Nevertheless, the phosphorus recovery rate improved with the increase of side stream ratio. It was also observed that the TN removal rate dramatically decreased to 50.9% when the side stream ratio increased to 1/2. Consequently, a side stream ratio of 1/3 was found to be the optimal condition in the whole experimental stage, and EBPR system under low dissolved oxygen condition combined with phosphorus recovery through extracting side stream could greatly improve the economic and environmental benefits.

[Phosphorus Removal Performance in EBPR System under Extra-low Dissolved Oxygen Condition].

Two sequencing batch reactors (SBRs) were operated with alternating anaerobic/oxic (An/O) for 127 days to study the phosphorus removal efficiency and process performance of the EBPR under different dissolved oxygen gradient. For the reactor (R1) in which DO was not controlled and measured as high as 6 mg·L-1 during the aerobic stage, a stable phosphorus removal performance was achieved in the former 65 days during the operational period. The phosphorus removal efficiency was greater than 95.9% and the total phosphorus in effluent was less than 0.5 mg·L-1. However, the phosphorus removal performance subsequently deteriorated after 65 days and completely broke up until 97 day due to long-term excessive aeration. Throughout the operational period,only 39.4% of effluent TP met the national wastewater discharge standard A. For the test reactor (R2) in which DO was controlled at the levels of 2, 1, 0.5, 0.2, 0.1 mg·L-1 during the aerobic stage, respectively, the phosphorus removal performance showed a slight fluctuation at the beginning of each stage but rapidly increased to a stable state. According to the statistics, 94.6% of effluent TP in reactor R2 could meet the national wastewater discharge standard A throughout the operational period. In only 6 days out of the 127 days, effluent TP failed to meet the national standard and the process performance was far better than that of R1. The specific phosphate uptake rate under DO=2 mg·L-1 was found to be nearly the maximum, but it was greatly influenced by the low DO. In addition, limited filamentous bulking resulted from low organic matter degradation rate under extra-low DO level (0.1 mg·L-1) was observed. Nevertheless, 100% of effluent TP during this stage could meet the national standard. As a result, the phosphorus removal in micro-aerobic EBPR system for saving energy was feasible.

Ethanol extract of propolis protects macrophages from oxidized low density lipoprotein-induced apoptosis by inhibiting CD36 expression and endoplasmic reticulum stress-C/EBP homologous protein pathway.

BACKGROUND: Ethanol extract of propolis (EEP), rich in flavones, has been known for various biological activities including antioxidant, antiinflammatory and antibiotic activities. Our previous studies have shown that EEP protects endothelial cells from oxidized low-density lipoprotein (ox-LDL)-induced apoptosis and inhibits atherosclerotic lesion development. In this present study, we explored the protective effect of EEP on ox-LDL-induced cytotoxicity in macrophages and specifically the endoplasmic reticulum (ER) stress-C/EBP homologous protein (CHOP) pathway-mediated apoptosis. METHODS: EEP was prepared and the total flavonoids content of EEP was determined by the colorimetric method of Chinese Standard (GB/T 20574-2006). The effects of EEP on lipid accumulation, cytotoxicity and apoptosis in RAW264.7 cells induced by ox-LDL or tunicamycin (TM, an ER stress inducer) were assayed using oil red O staining, MTT assay, flow cytometric analysis and so on. Immunofluorescence, Western blot and real time-PCR analysis were then used to further investigate the molecular mechanisms by which EEP protects macrophages from ox-LDL-induced apoptosis. 4-phenylbutyric acid (PBA), an ER stress inhibitor, was used as a positive control. RESULTS: EEP (7.5, 15 and 30 mg/L) not only attenuated ox-LDL-induced lipid accumulation in RAW264.7 macrophages in a dose-dependent manner but also inhibited the decreased cell viability and the increased lactate dehydrogenase (LDH) leakage, caspase-3 activation and apoptosis induced by ox-LDL or tunicamycin (TM, a classical ER stress inducer), which were similar to 4-phenylbutyric acid (PBA, an inhibitor of ER stress) treatment. In addition, like PBA, EEP significantly suppressed the ox-LDL- or TM-induced activation of ER stress signaling pathway including the phosphorylation of double-stranded RNA-activated protein kinase-like ER kinase (PERK) and eukaryotic translation initiation factor 2α (eIF2α) as well as upregulation of glucose regulated protein 78 (GRP78) and the pro-apoptotic protein CHOP. Furthermore, EEP significantly suppressed ox-LDL intake by macrophages and the upregulation of CD36 induced by ox-LDL. CONCLUSION: These data indicate that EEP may protect macrophages from ox-LDL-induced apoptosis and the mechanism at least partially involves its ability to suppress the CD36-mediated ox-LDL intake and subsequent activation of ER stress-CHOP signalling pathway.

[Long-Term Inhibition of FNA on Aerobic Phosphate Uptake and Variation of Phosphorus Uptake Properties of the Sludge].

An alternating anaerobic/oxic ( An/O) sequencing batch reactor (SBR) was employed to investigate the long-term inhibitory effect of free nitrous acid (FNA) on aerobic phosphorus uptake performance and variation of phosphorus uptake properties of the sludge by adding nitrite. The reactor was started up under the condition of 21-23 degrees C. The results showed that FNA had no impact on phosphate release and uptake capacities of the sludge. However, the specific phosphate release/uptake rates was found to be higher. As FNA concentration (measure by HNO2-N) was lower than 0.53 x 10(-3) mg x L(-1), phosphorus removal efficiency of the system was higher than 96.9%. When the FNA concentration was increased to 0.99 x 10(-3) mg x L(-1), 1.46 x 10(-3) mg x L(-1) and 1.94 x 10(-3) mg x L(-1), the phosphorus removal performance deteriorated rapidly. The phosphorus removal efficiency was recovered to 64.42%, 67.33% and 44.14% after 50, 12 and 30 days, respectively, which implied the deterioration of phosphorus removal performance caused by FNA inhibition could be recovered and long-term acclimation could shorten the recovery process. Notably, increasing nitrite consumption appeared during aerobic phase with the concentration of FNA below 1.46 x 10(-3) mg x L(-1). It was also observed that the phosphorus uptake properties of the sludge varied after long-term inhibition. Nitrate and nitrite type anoxic phosphorus uptake capacity was increased by 3.35 and 3.86 times, respectively, suggesting long-term dosing FNA may facilitate the denitrifying of polyphosphate in organisms utilizing nitrite as electron acceptor. Moreover, long-term acclimation favored sludge settling.