miR-34 increases in vitro PANC-1 cell sensitivity to gemcitabine via targeting Slug/PUMA.

miR-34 was deregulated in tumor tissues compared with corresponding noncancerous tissue samples. Furthermore, miR-34 may contribute to cancer-stromal interaction associated with cancer progression. However, whether miR-34 could decrease chemoresistance of cancer cells to chemotherapeutic agent remains unclear. In our study, we examined whether overexpression of miR-34 could sensitize gemcitabine -mediated apoptosis in human pancreatic cancer PANC-1 cells. We found that miR-34 markedly induced gemcitabine -mediated apoptosis in PANC-1 cells. miR-34 induced down-regulation of Slug expression and upregulation of p53 up-regulated modulator of apoptosis (PUMA) expression. The over-expression of Slug or downregulation of PUMA by Slug cDNA or PUMA siRNA transfection markedly blocked miR-34-induced gemcitabine sensitization. Furthermore, miR-34 induced PUMA expression by downregulation of Slug. Taken together, our study demonstrates that miR-34 enhances sensitization against gemcitabine-mediated apoptosis through the down-regulation of Slug expression, and up-regulation of Slug-dependent PUMA expression.

Potential rat model of anxiety-like gastric hypersensitivity induced by sequential stress.

AIM: To establish a rat model of anxiety-like gastric hypersensitivity (GHS) of functional dyspepsia (FD) induced by novel sequential stress. METHODS: Animal pups were divided into two groups from postnatal day 2: controls and the sequential-stress-treated. The sequential-stress-treated group received maternal separation and acute gastric irritation early in life and restraint stress in adulthood; controls were reared undisturbed with their mothers. Rats in both groups were followed to adulthood (8 wk) at which point the anxiety-like behaviors and visceromotor responses to gastric distention (20-100 mmHg) and gastric emptying were tested. Meanwhile, alterations in several anxiety-related brain-stomach modulators including 5-hydroxytryptamine (5-HT), γ-aminobutyric acid (GABA), brain-derived neurotrophic factor (BDNF) and nesfatin-1 in the rat hippocampus, plasma and gastric fundus and the 5-HT1A receptor (5-HT1AR) in the hippocampal CA1 subfield and the mucosa of the gastric fundus were examined. RESULTS: Sequential-stress-treated rats simultaneously demonstrated anxiety-like behaviors and GHS in dose-dependent manner compared with the control group. Although rats in both groups consumed similar amount of solid food, the rate of gastric emptying was lower in the sequential-stress-treated rats than in the control group. Sequential stress significantly decreased the levels of 5-HT (51.91 ± 1.88 vs 104.21 ± 2.88, P < 0.01), GABA (2.38 ± 0.16 vs 5.01 ± 0.13, P < 0.01) and BDNF (304.40 ± 10.16 vs 698.17 ± 27.91, P < 0.01) in the hippocampus but increased the content of nesfatin-1 (1961.38 ± 56.89 vs 1007.50 ± 33.05, P < 0.01) in the same site; significantly decreased the levels of 5-HT (47.82 ± 2.29 vs 89.45 ± 2.61, P < 0.01) and BDNF (257.05 ± 12.89 vs 536.71 ± 20.73, P < 0.01) in the plasma but increased the content of nesfatin-1 in it (1391.75 ± 42.77 vs 737.88 ± 33.15, P < 0.01); significantly decreased the levels of 5-HT (41.15 ± 1.81 vs 89.17 ± 2.31, P < 0.01) and BDNF (226.49 ± 12.10 vs 551.36 ± 16.47, P < 0.01) in the gastric fundus but increased the content of nesfatin-1 in the same site (1534.75 ± 38.52 vs 819.63 ± 38.04, P < 0.01). The expressions of 5-HT1AR in the hippocampal CA1 subfield and the mucosa of the gastric fundus were down-regulated measured by IHC (Optical Density value: Hippocampus 15253.50 ± 760.35 vs 21149.75 ± 834.13; gastric fundus 15865.25 ± 521.24 vs 23865.75 ± 1868.60; P < 0.05, respectively) and WB (0.38 ± 0.01 vs 0.57 ± 0.03, P < 0.01) (n = 8 in each group). CONCLUSION: Sequential stress could induce a potential rat model of anxiety-like GHS of FD, which could be used to research the mechanisms of this intractable disease.

Reflux characteristics of 113 GERD patients with abnormal 24-h multichannel intraluminal impedance-pH tests.

OBJECTIVE: To analyze reflux parameters by means of combined multichannel intraluminal impedance and pH (MII-pH) monitoring in patients with gastroesophageal reflux disease (GERD) symptoms off medication, and to find the reflux characteristics of Chinese GERD patients and the influences of gender, age, body posture, and body mass index (BMI) on gastroesophageal reflux (GER). METHODS: Between Dec. 2008 and May 2014, 125 patients with typical GERD symptoms were subjected to 24-h MII-pH monitoring. Twelve patients with normal MII-pH profiles were not considered for analysis. The reflux parameters of 113 GERD patients with abnormal MII-pH results were analyzed. RESULTS: (1) DeMeester scores were above the normal range in 46.90% (53/113) of GERD patients. Weakly acidic refluxes were prevalent in GERD patients, and the frequency of abnormal weakly acidic reflux was 75.22% (85/113). The frequencies of abnormal symptom index (SI) and symptom association probability (SAP) were 19.47% (22/113) and 14.16% (16/113), respectively. (2) The frequencies of DeMeester scores, the %time at pH<4, and the numbers of reflux episodes and of long reflux episodes >5 min were significantly higher in male patients than in female patients. (3) The %time at pH<4 was much higher during upright periods than during supine periods. During supine periods, 31.86% (36/113) of GERD patients had delayed bolus clearance time, compared with 19.47% (22/113) during upright periods. (4) The number of abnormal DeMeester scores, %time at pH<4, and the number of acid refluxes during upright periods were significantly higher in obese GERD patients than in GERD patients with a normal BMI. Overweight GERD patients also had many more acid refluxes during upright periods than GERD patients with a normal BMI. CONCLUSIONS: Weakly acidic refluxes were prevalent in Chinese GERD patients. The factors male, gender, upright position, obesity (BMI≥25), but not age, may increase the frequency and severity of GER.

Rapid determination of dopamine and its metabolites during in vivo cerebral microdialysis by routine high performance liquid chromatography with electrochemical detection.

OBJECTIVE: To determine dopamine and its metabolites during in vivo cerebral microdialysis by routine high performance liquid chromatography with electrochemical detection. METHODS: Microdialysis probes were placed into the right striatum of Wistar rat brains and perfused with Ringer's solution at a rate of 1.5 microL/min. A reverse phase HPLC with electrochemistry was used to assay DA, DOPAC, and HVA after cerebral microdialysates were collected every 20 minutes from awake and freely moving rats. In order to identify the reliability of this method, its selectivity, linear range, precision and accuracy were tested and the contents of DA, DOPAC, and HVA in rat microdialysates were determined. RESULTS: The standard curve was in good linear at the concentration ranging from 74 nmol/L to 1.5 micromol/L for DOPAC (r2=0.9996), from 66 nmol/L to 1.3 micromol/L for DA (r2=1.0000) and from 69 nmol/L to 1.4 micromol/L for HVA (r2=0.9992). The recovery of DOPAC (0.30, 0.77, 1.49 micromol/L), DA (0.26, 0.69, 1.32 micromol/L), and HVA (0.27, 0.71, 1.37 micromol/L) was 82.00+/-1.70%, 104.00+/-4.00%, 98.70+/-3.10%; 92.30+/-1.50%, 105.30+/-2.30%, 108.00+/-2.00%; 80.00+/-7.80%, 107.69+/-8.00%, and 108.66+/-3.10%, respectively at each concentration. Their intra-day RSD was 3.3%, 3.4%, and 2.5%, and inter-day RSD was 4.2%, 2.3%, and 5.6%, respectively. The mean extracellular concentrations of DOPAC, DA, and HVA in rat brain microdialysates were 10.7, 2.4, and 9.2 micromol/L (n=6), respectively. CONCLUSION: The findings of our study suggested that the simple, accurate and stable method can be applied to basic researches of diseases related to monoamines neurotransmitters by cerebral microdialysis in rats.

Echinacoside prevents the striatal extracellular levels of monoamine neurotransmitters from diminution in 6-hydroxydopamine lesion rats.

We investigated the effects of echinacoside, a phenylethanoid glycoside isolated and purified from the stems of Cistanche salsa, a Chinese herbal medicine, on the striatal extracellular levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in 6-hydroxydopamine (6-OHDA) lesion rats. Seven days after 6-OHDA was injected into the right striatum of rats, the striatal extracellular levels of DA, DOPAC and HVA fell significantly (P<0.01 vs. vehicle), as demonstrated by the method of cerebral microdialysis and high performance liquid chromatography with electrochemical detection. However, simultaneous treatment with echinacoside (7.0, 3.5mg/kg) attenuated the diminution of them (P<0.01 vs. model). The results implied that echinacoside could protect the striatal dopaminergic neurons from injury induced by 6-OHDA and may be useful in the prevention and treatment of Parkinson's disease (PD).

[Effects of tetramethylpyrazine on brain oxidative damage induced by intracerebral perfusion of L-DOPA in rats with Parkinson's disease].

OBJECTIVE: To observe the effects of tetramethylpyrazine (TMP) on brain oxidative damage induced by intracerebral perfusion of levodopa (L-DOPA) in rats with Parkinson's disease (PD). METHODS: PD model rats were induced by intracerebral injection of 6-hydroxyl dopamine (6-OHDA) and perfused in brain with L-DOPA using microdialysis technique. Changes in levels of 2,3-dihydroxy benzyl acid (2.3-DHBA) and 2,5-dihydroxy benzyl acid (2,5-DHBA) in striatum of rats, formed by extracellular hydroxyl radical from salicylic acid capturing, were dynamically observed at various time points by HPLC-ED. RESULTS: After treatment with L-DOPA, 2,3-DHBA and 2,5-DHBA in the model group showed significantly higher levels at 6 and 7 time points as compared with those in the sham-operated group at the corresponding time points (P <0.05 or P< 0.01), while these abnormal elevations were significantly inhibited in the TMP treated groups, either in large or small dose (P<0.05 or P<0.01). CONCLUSION: TMP could reduce the L-DOPA induced brain oxidative damage in PD rats.