Enhanced cyclooxygenase-2 activity leads to intestinal dysmotility following hemorrhagic shock

ABSTRACT PURPOSE: To test whether hemorrhagic shock (HS) increases the Cyclooxygenase-2 (COX-2) expression in the intestine and whether this enhanced COX-2 expression mediates the intestinal dysmotility after HS. METHODS: Male Wistar rats were randomly divided into HS sham group and HS group. At 180 min following HS establishment, the duodenum samples were harvested to assess the motility function, protein expression of COX-2 and the downstream products of COX-2, prostaglandins. RESULTS: Examination of motility function ex vivo showed that the contractile response to acetylcholine of smooth muscle strips of rats subjected to HS was significantly suppressed. A COX-2 inhibitor, NS-398, abolished this depressed contractile response after HS. Western blotting revealed an increased protein expression of COX-2 in intestinal tissues of HS rats. Immunohistochemical examination indicated that intestine tissues of HS rats were manifested by part of villous expansion and disruption, a large amount of COX-2 positive cells appearance in lamina propria and submucosa. Furthermore, the contents of prostaglandin E2 was significantly increased in intestinal tissues of HS rats. CONCLUSION: The enhanced COX-2/ prostaglandin E2 involves in the hemorrhagic shock induced intestinal dysmotility.

Study of the effect of inorganic and organic complexes of arsenic metal on the status of GSH in T. cells and B. cells of blood

Arsenic is a major threat to large part of the population due to its carcinogenic nature. The toxicity of Arsenic varies with its chemical form and oxidation states. Glutathione [GSH], a major intra-cellular tripeptide plays a major role in arsenic detoxification. The present study was designed to provide insight into the extent of changes in GSH level by inorganic arsenic in the form of Arsenic trioxide [ATO] and organic arsenic in the form of nitro benzene arsenic acid [NBA]. Lymphocytes [T.cells and B.cells] were investigated for determination of change in GSH metabolic status caused by arsenic. The depletion of GSH level positively correlated with increasing arsenic concentration and time of incubation. The decline in GSH level was consistent with increasing pH and physiological temperature. Our findings show that changes in GSH status produced by Arsenic could be due to adduct [As-[SG][3]] formation. This change in GSH metabolic status provides information regarding mechanism of toxicity of inorganic and organic arsenicals. These findings are important for the rational design of antidote for the prevention of arsenic induced toxicity

Cyclooxygenase-2 blockade inhibits accumulation and function of myeloid-derived suppressor cells and restores T cell response after traumatic stress / 华中科技大学学报（医学）（英德文版）

Myeloid-derived suppressor cells (MDSCs) play a crucial role in T cell dysfunction, which is related to poor outcome in patients with severe trauma. Cyclooxygenase-2 (Cox-2) contributes to immune disorder in trauma and infection via production of prostaglandin E2. However, the role of Cox-2 in the accumulation and function of MDSCs after traumatic stress has not been fully elucidated. In the present study, we treated murine trauma model with NS398, a selective Cox-2 inhibitor. Then the percentages of CD11b+/Gr-1+ cells, proliferation and apoptosis of CD4+ T cells were determined. Arginase activity and arginase-1 (Arg-1) protein expression of splenic CD11b+/Gr-1+ cells, and delayed-type hypersensitivity (DTH) response were analyzed. The results showed that Cox-2 blockade significantly decreased the percentages of CD11b+/Gr-1+ cells in the spleen and bone marrow 48 and 72 h after traumatic stress. NS398 inhibited arginase activity and down-regulated the Arg-1 expression of splenic CD11b+/Gr-1+ cells. Moreover, NS398 could promote proliferation and inhibit apoptosis of CD4+ T cells. It also restored DTH response of traumatic mice. Taken together, our data revealed that Cox-2 might play a pivotal role in the accumulation and function of MDSC after traumatic stress.

Case of Acute Methemoglobinemia Caused by Nitrobenzene Ingestion / 대한내과학회지

Nitrobenzene is a poisonous agent, not commonly encountered in clinical practice, which belongs to the aniline dyes. Ingestion of nitrobenzene may cause methemoglobinemia, a condition in which the iron in hemoglobin is oxidized from the ferrous state to the ferric state, resulting in the inability to transport oxygen. A 41-year-old man presented with the clinical features of methemoglobinemia after drinking nitrobenzene. The patient was treated conservatively with intravenous methylene blue. We report a case of acute methemoglobinemia due to ingestion of nitrobenzene.

Cyclooxygenase-2 inhibitors modulate skin aging in a catalytic activity-independent manner

It has been proposed that the pro-inflammatory catalytic activity of cyclooxygenase-2 (COX-2) plays a key role in the aging process. However, it remains unclear whether the COX-2 activity is a causal factor for aging and whether COX-2 inhibitors could prevent aging. We here examined the effect of COX-2 inhibitors on aging in the intrinsic skin aging model of hairless mice. We observed that among two selective COX-2 inhibitors and one non-selective COX inhibitor studied, only NS-398 inhibited skin aging, while celecoxib and aspirin accelerated skin aging. In addition, NS-398 reduced the expression of p53 and p16, whereas celecoxib and aspirin enhanced their expression. We also found that the aging-modulating effect of the inhibitors is closely associated with the expression of type I procollagen and caveolin-1. These results suggest that pro-inflammatory catalytic activity of COX-2 is not a causal factor for aging at least in skin and that COX-2 inhibitors might modulate skin aging by regulating the expression of type I procollagen and caveolin-1.

Proliferation of Hepatic Oval Cells via Cyclooxygenase-2 and Extracellular Matrix Protein Signaling during Liver Regeneration Following 2-AAF/Partial Hepatectomy in Rats

BACKGROUND/AIMS: In the 2-acetylaminofluorene (2-AAF)/70% partial hepatectomy (PHx) model, the mechanism underlying the differentiation of activated hepatic oval cells (HOCs) into hepatocytes and bile ductile cells is unclear. We investigated the role of cyclooxygenase-2 (COX-2) in HOCs and the relationship between COX-2 and extracellular matrix proteins in cellular proliferation. METHODS: Reverse transcription-polymerase chain reaction, immunohistochemical staining, and Western blotting were used to assess COX-2 expression. The co-localization of COX-2 with Thy1, c-Met, epithelial cell adhesion molecule, and alpha-smooth muscle actin was also examined. Additionally, we investigated whether connective tissue growth factor (CTGF), fibronectin (FN), extracellular signal-regulated kinase 1/2 (P-ERK1/2), and AKT were expressed in HOCs. RESULTS: The expression of COX-2, prostaglandin E2 receptors, and c-Met was upregulated in HOCs. However, HOCs treated with the COX-2 inhibitor NS398 showed decreased COX-2, CTGF, FN, and AKT expression, whereas P-ERK1/2 was unaffected. Additionally, NS398 inhibited HOC proliferation, but not the proliferation of HOCs cultured on FN-coated dishes. Furthermore, the proliferative response of HOCs treated with NS398 was reversed by hepatic growth factor treatment. CONCLUSIONS: These results suggest that HOC proliferation is mediated through COX-2, extracellular FN expression, and AKT activation. Thus, COX-2 plays an important role in HOC proliferation following acute injury.

Recovery of aniline from wastewater by nitrobenzene extraction enhanced with salting-out effect / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Nitrobenzene extraction enhanced by salting-out effect was employed to recover aniline from wastewater at 25 degrees C.</p><p><b>METHOD</b>Batchwise experiments were conducted to elucidate the influence of various operating variables on the extracting performance, including acidity of wastewater, initial aniline concentration, ratios of solvent to wastewater, extraction stages, concentrations and different types of inorganic salts, such as NaCl, KCl, Na(2)SO(4), CaCl(2) and K(2)SO(4).</p><p><b>RESULTS</b>Nitrobenzene with a concentration of 20% and a pH value of 9.1 at the temperature of 25 degrees C together with NaCl of a concentration of 14 wt.% realized nearly 100% aniline recovery at the fifth stage of wastewater treatment.</p><p><b>CONCLUSIONS</b>High pH values and volume ratios of nitrobenzene/wastewater are more suitable for recovery of aniline. In addition, recovery of aniline is significantly elevated with increase of the concentration of salts, whose promoting effects are in the following order: NaCl>Na(2)SO(4)>K(2)SO(4)>CaCl(2)>KCl on the weight basis of wastewater. Furthermore, aniline in wastewater can be almost completely recovered by five-stage sequential nitrobenzene extraction, which is promoted continuously by the salting-out effect.</p>

Effect of COX-2 inhibitor on the expression of BCL-3 and cyclin D1 in human colon cancer cell line SW480 / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To study the effects of NS398, a selective cyclooxygenase-2 (COX-2) inhibitor, on the transcription and translation of BCL-3 and its regulatory gene cyclin D1 in colon cancer cell line SW480.</p><p><b>METHODS</b>Human colon cancer cells SW480 were divided into two groups: SW480 cells in experimental group were treated with NS398 in different concentrations(25 micromol/L, 50 micromol/L, 100 micromol/L and 200 micromol/L) for 48 h or 72 h. SW480 cells in control group were treated with media which did not contain NS398. Then the expressions of BCL-3 and cyclin D1 were detected by RT-PCR, Western blot, and immunocytochemistry.</p><p><b>RESULTS</b>At 48 hours RT-PCR showed that BCL-3 mRNA and cyclin D1 mRNA decreased in a dose-dependent manner in the experimental group. However, there were no significant differences in the levels of BCL-3 protein and cyclin D1 protein between two groups (P>0.05). At 72 hours, BCL-3 protein and cyclin D1 protein also decreased in a dose-dependent manner in the experimental group. When the concentration of NS398 reached 100 micromol/L, the differences between the two groups in the expression of BCL-3 mRNA and protein became statistically significant (P<0.01). When the concentration of NS398 reached 50 micromol/L, the differences in the expression of cyclin D1 mRNA and protein were statistically significant (P<0.05).</p><p><b>CONCLUSIONS</b>BCL-3 is expressed in colon cancer cell line SW480. COX-2 inhibitor can inhibit the expression of BCL-3 and cyclin D1 in a dose-dependent manner. NS398 may down-regulate the expression of cyclin D1 through BCL-3.</p>

Nonsteroidal anti-inflammatory drug NS398 induces RECK expression in the animal model of prostate cancer / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the regulatory effect of the nonsteroidal anti-inflammatory drug NS398 on the expression of the RECK gene in the animal model of prostate cancer.</p><p><b>METHODS</b>Nude mouse models of prostate cancer were divided into an experimental and a control group, the former fed with NS398 at 0.1 mg/g per day for 10, 20 and 30 days, while latter left without medication. All the mice were killed at 30 days, the mRNA expressions of RECK and MMP-9 in the tumor tissues measured by RT-PCR, and the protein level of RECK evaluated by Western blot.</p><p><b>RESULTS</b>Both the mRNA and protein expressions of RECK were increased, while the level of MMP-9 decreased, in an obviously time-dependent manner in the experimental group as compared with the control.</p><p><b>CONCLUSION</b>NS398 obviously inhibits the pathogenesis and metastasis of prostate cancer, which may be attributed to its induction of the expression of the RECK gene and suppression of the expression of MMP-9.</p>

The role and mechanisms of cyclooxygenase-2 inhibitors on the proliferation of hepatic stellate cell / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To observe the effects of NS-398 on proliferation of hepatic stellate cells (HSCs) in vitro, and to investigate the possible molecule mechanism.</p><p><b>METHODS</b>HSCs were incubated with different concentrations of NS-398. The effects of NS-398 on cell proliferation was detected by MTT colormetric assay. The cell cycle of HSCs was analyzed by Flow Cytometry (FCM), cyclooxygenase-2 (COX-2) and proliferating cell nuclear antigen (PCNA) proteins in HSCs were detected by immunocytochemistry.</p><p><b>RESULTS</b>Administration of 20-160 micromol/L NS-398 significantly inhibited HSCs proliferation in dose-dependent manner compared with the control group (P less than 0.01). After treated with NS-398 at concentrations of 90, 120, and 150 micromol/L for 48 h, the number of HSCs in G(2)/M phase increased and the number of HSCs in G(0)/G(1) phase decreased (P less than 0.05); Incubated with 120 micromol/L NS-398 for 48 h, percentage of masculine cell of PCNA was 28.91%+/-0.11%, which was significantly lower than that of the control group (85.99%+/-0.13%) (P less than 0.01). Percentage of masculine cell of COX-2 was 13.80%+/-0.43%, which was not significantly different from that of the control group (14.07%+/-0.59%) (P more than 0.05).</p><p><b>CONCLUSIONS</b>NS-398 could inhibit the proliferation of HSC-T6 and arrest HSCs in G2/M phase. Down-regulation of PCNA protein may partially accounted for the proliferation inhibition effect on HSCs induced by NS-398.</p>

Celecoxib increased cellular ATRA sensitivity of human colon cancer cell lines through COX-2-independent mechanisms / 药学学报

Retinoid resistance has limited clinical activity of retinoids as differentiation-inducing and apoptosis-inducing drugs. The present study was designed to investigate whether celecoxib (selective COX-2 inhibitor) has effects on cellular retinoid sensitivity of human colon cancer cell lines and its possible mechanism. Cell viability was measured by MTT assay. Apoptosis was detected by Annexin-V/PI staining and flow cytometry assay. PGE2 production was measured by ELISA assay. Expression of RARbeta was assayed by Western blotting. The results showed that celecoxib enhanced the inhibitory effect of ATRA in both COX-2 high-expressing HT-29 and COX-2 low-expressing SW480 cell lines. Further study showed the ATRA and celecoxib combination induced greater apoptosis, and the addition of PGE2 did not affect the number of apoptotic cells induced by the combination. Moreover, NS398 (another selective COX-2 inhibitor) did not affect the inhibitory effects of ATRA on both cell lines. Western blotting showed that the expression of RARbeta in HT-29 cell lines increased in celecoxib group and combination group. And the addition of PGE2 did not affect the expression of RARbeta induced by celecoxib either. In conclusion, celecoxib increased expression of RARbeta and cellular ATRA sensitivity through COX-2-independent mechanisms, which may provide a potential strategy for combination therapy.

Down-regulation of survivin in growth inhibition of hepatoma cells induced by a selective cyclooxygenase-2 inhibitor / 대한간학회지

BACKGROUND/AIMS: Cyclooxygenase-2 (COX-2) inhibitors reportedly inhibit the growth of hepatocellular carcinoma (HCC) via caspase-dependent or caspase-independent apoptosis, which is due to COX-2 being associated with hepatocarcinogenesis. Survivin is highly expressed in most human cancers, but the mechanism regulating survivin expression remains unclear. We investigated the regulatory expression of survivin in selective-COX-2-inhibitor-induced growth inhibition of hepatoma cells. METHODS: After treatment with NS-398 (a selective COX-2 inhibitor) at various concentrations (10, 50, 100, 150, and 200 micrometer), the growth inhibition of Hep3B hepatoma cells was assessed by an MTT cell-viability assay, DNA fragmentation gel analysis, and flow cytometry. The expression of survivin transcript was analyzed by reverse-transcription polymerase chain reactions. RESULTS: NS-398 inhibited the growth of hepatoma cells by an amount dependent on the concentration and the time since treatment. Apoptotic DNA ladder and flow-cytometry shifting to the sub-G1 phase were revealed in NS-398-induced growth inhibition of hepatoma cells. NS-398 suppressed the expression of the survivin gene in a concentration- and time-dependent manner. CONCLUSIONS: Survivin was down-regulated in the growth inhibition of hepatoma cells induced by a selective COX-2 inhibitor, NS-398, in a concentration- and time-dependent manner. These results suggest the therapeutic inhibition of COX-2 via suppression of survivin in HCC.

Nonsteroidal anti-inflammatory drug NS398 regulates the RECK gene expression in the prostate carcinoma strain DU145 / 中华男科学杂志

<p><b>OBJECTIVES</b>To investigate the regulative effect of the nonsteroidal anti-inflammatory drug NS398 on the RECK gene in the prostate carcinoma strain DU145.</p><p><b>METHODS</b>DU145 was treated with various concentrations of NS398 for 48 hours. The mRNA level was measured by RT PCR technique and the expression of the RECK protein determined by Western blot.</p><p><b>RESULTS</b>The mRNA level of the RECK gene was obviously higher, while the MMP9 level markedly lower in the treated group than in the control, and so was the expression of the RECK protein.</p><p><b>CONCLUSION</b>NS398 induces the expression of the RECK gene, which might be the mechanism of its anti-tumor effect.</p>

Cyclooxygenase-2 inhibitor inhibits hippocampal synaptic reorganization in pilocarpine-induced status epilepticus rats / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

<p><b>OBJECTIVE</b>To examine modulations caused by cyclooxygenase-2 (COX-2) inhibitors on altered microenvironments and overbalanced neurotransmitters in pilocarpine-induced epileptic status rats and to investigate possible mechanisms.</p><p><b>METHODS</b>Celecoxib (a COX-2 inhibitor) was administered 45 min prior to pilocarpine administration. The effects of COX-2 inhibitors on mIPSCs (miniature GABAergic inhibitory postsynaptic currents) of CA3 pyramidal cells in the hippocampus were recorded. Expressions of COX-2, c-Fos, newly generated neurons, and activated microgliosis were analyzed by immunohistochemistry, and expressions of alpha-subunit of gamma-amino butyric acid (GABA(A)) receptors and mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MAPK/ERK) activity were detected by Western blotting.</p><p><b>RESULTS</b>Pretreatment with celecoxib showed protection against pilocarpine-induced seizures. Celecoxib prevented microglia activation in the hilus and inhibited the abnormal neurogenesis and astrogliosis in the hippocampus by inhibiting MAPK/ERK activity and c-Fos transcription. Celecoxib also up-regulated the expression of GABA(A) receptors. NS-398 (N-2-cyclohexyloxy-4-nitrophenyl-methanesulfonamide), another COX-2 inhibitor, enhanced the frequency and decay time of mIPSCs.</p><p><b>CONCLUSION</b>The COX-2 inhibitor celecoxib decreased neuronal excitability and prevented epileptogenesis in pilocarpine-induced status epilepticus rats. Celecoxib regulates synaptic reorganization by inhibiting astrogliosis and ectopic neurogenesis by attenuating MAPK/ERK signal activity, mediated by a GABAergic mechanism.</p>

Effect of NS-398 on cyclooxygenase-2 expression and proliferation of HepG2 cells / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate anticancer effect and molecular mechanism of N-[(Cyclohexyloxy)-4-nitrophenyl] methanesulfonamide on HepG2 cells in vitro.</p><p><b>METHODS</b>HepG2 cells were treated with various concentrations (100, 200, 300, 400 micromol/L) of NS-398 [selective for cyclooxygenase 2 (COX-2) inhibition]. Cell growth was measured by MTT method, DNA fragmentation gel analysis was used to analyze the apoptosis cells, DNA ploidy and apoptotic cell percentage were examined by flow cytometry (FCM). PGE2 concentration was measured by radioimmunoassay method. The expressions of COX-2 were also examined by Western blot analysis.</p><p><b>RESULTS</b>NS-398 inhibited HepG2 cell proliferation and induced apoptosis in a concentration-dependent manner. DNA ploidy analysis showed that S phase cells were significantly decreased and quiescent G1 phase was accumulated with NS-398 concentration increasing. The IC50 of 24 hours was 300 micromol/L. The release of PGE2 was significantly reduced in HepG2 cells with the values of NS-398 being (0.70 +/- 0.02), (0.48 +/- 0.02), (0.29 +/- 0.01) and (0.18 +/- 0.01) respectively, as compared with control group (0.03 +/- 0.01). NS-398 could inhibit the activity and expression of COX-2, with higher concentration, it can significantly down-regulate the expression of COX-2 (t = 3.736, 1.623, 1.810, 2.587, P < 0.01).</p><p><b>CONCLUSION</b>NS-398 might significantly inhibit the proliferation of HepG2 cells and induce apoptosis. The mechanisms were related with the accumulation of quiescent G1 phase and the inhibition of COX-2 activity.</p>

Human Cytomegalovirus Induces Intercellular Adhesion Molecule-1 Expression in a Monocytic Cell Line, THP-1

It has been reported that inflammatory diseases such as pneumonitis, retinitis, and hepatitis are associated with human cytomegalovirus (HCMV). Intercellular adhesion molecule (ICAM)-1 is an important inflammatory mediator, helping monocytes adhere to endothelial cells when tissues are infected by pathogen including the HCMV. However, little is known about the mechanism of ICAM-1 stimulation by the HCMV infection in monocytes. In this study, a monocytic cell line THP-1 was used to understand ICAM-1 expression by the HCMV infection. Flow cytometric analyses demonstrated that ICAM-1 was stimulated by the HCMV in THP-1 cells with maximum at 24 hours post infection. The stimulated ICAM-1 expression was dependent on the amount of input virus. In order to understand the mechanism of ICAM-1 stimulation during the HCMV infection, cells were treated with specific inhibitors of key elements in inflammation: NF-kappaB inhibitor PDTC, cyclooxygenase 2 inhibitor NS398, and MEK inhibitor PD98059. Flow cytometric analyses revealed that ICAM-1 expression was decreased when treated with PDTC, but not with NS398 or PD98059. Thus, it is suggested that HCMV-induced ICAM-1 expression in THP-1 cells is associates with NF-kappaB.

Percutaneous Transthoracic Cutting Needle Biopsy of Pulmonary Lesions: Comparison of the Use of 18 and 20 Gauge Needles

PURPOSE: We evaluated the usefulness of a CT guided percutaneous transthoracic cutting needle biopsy (PCNB) using a 20 gauge (G) needle for pulmonary lesions after a comparison with the use of an 18 G needle for diagnostic accuracy and complications. MATERIALS AND METHODS: From August 2005 to July 2007, 433 patients underwent a CT guided PCNB. A total of 191 patients were excluded from the study as these patients had benign lesions seen after PCNB, but did not receive a confirmation biopsy or undergo follow-up (> 1 year). We evaluated the diagnostic accuracy for the use of PCNB using the Chi-squared test and analyzed which factors (location and size of lesions, diameter of the needle, distance between the pleura and lesions, presence or not of emphysema) were related to occurrence of a pneumothorax after PCNB using a multi-variant regression test. RESULTS: The diagnostic accuracy for malignant lesions with the use of an 18 G and a 20 G needle were 95.4% and 97%, respectively. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the use of an 18 G needle were 95.7 %, 100%, 100%, and 91.6%. The sensitivity, specificity, PPV, and NPV were 97.8%, 100%, 100%, and 95.0% for the use of a 20 G needle. A pneumothorax occurred in 5.5% (24/433) of the cases and was closely related to the distance from the pleura to the lesions. CONCLUSION: CT guided PCNB with the use of a 20 gauge needle provided good diagnostic accuracy and the procedure is safe to perform.

Anti-tumor mechanisms and regulation of survivin by selective cyclooxygenase-2 inhibitor / 대한간학회지

No abstract available.

A simple method to differentiate between Mycobacterium tuberculosis and non-tuberculous mycobacteria directly on clinical specimens.

We report the applicability of testing susceptibility to paranitrobenzoic acid (PNB) directly on clinical samples as a rapid screening assay, to detect M. tuberculosis and differentiate it from non-tuberculous mycobacteria (NTM). One hundred smear positive sputum samples from patients with pulmonary tuberculosis attending the Department of Respiratory Medicine at VP Chest Institute, Delhi, were cultured on Löwenstein Jensen medium with and without 0.5 mg/ml paranitrobenzoic acid. Serial concentrations of known cultures of H37Rv, M. fortuitum, M. scrofulaceum and M. avium were used as controls in the study. After 3 weeks of incubation, growth was observed on all the drug free Löwenstein Jensen slants but none of the slants containing PNB, which inhibited the growth of M. tuberculosis. The cultures were further confirmed to be M. tuberculosis by niacin, nitrate and catalase tests. Direct susceptibility to PNB was thus found to be a simple, cheap and technically feasible method of preliminary identification of M. tuberculosis and its effective differentiation from NTM, which may be adapted for use at Level II laboratories, especially in developing countries.

The role of cyclooxygenase-2/prostanoid pathway in visceral pain induced liver stress response in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cyclooxygenase (COX) is the rate-limiting enzyme in the production of prostanoids from arachidonic acid. COX-2 is the inducible enzyme in the COX family, together with the prostanoids forms the COX-2/prostanoid pathway. Research showed that the COX-2/prostanoid pathway is activated in hepatic diseases and liver stress reaction, such as fibrogenesis, portal hypertension, carcinogenesis, and ischemic/reperfusion injury. But there was no report on visceral pain induced liver stress. This study was to investigate the role of the COX-2/prostanoid pathway in liver stress response in rat acute colitis visceral pain liver stress model.</p><p><b>METHODS</b>Fifty-three male SD rats were randomly divided into Naive, Model, NS398 treatment, and Morphine treatment groups. The rat acute colitis visceral pain liver stress model was established under anesthesia by the colonic administration of 0.5 ml of 6% acetic acid using a urethral catheter. NS398 and morphine were administrated 30 minutes prior to model establishment in NS398 and Morphine treatment groups respectively. Spontaneous activities and pain behavior were counted and the extent of colonic inflammation was assessed histologically. Liver tissue levels of Glutathione-S-Transferase (GST) activity, COX-2 mRNA, prostaglandin E2 (PGE2), thromboxane B2 (TXB2) and 6-Ketone-prostaglandin F1alpha (6-K-PGF1alpha) contents were assessed.</p><p><b>RESULTS</b>Thirty minutes after the colonic administration of acetic acid, a significant decrease in spontaneous activities and an increase in pain behaviors were observed in Model group (P < 0.01 and P < 0.05 respectively), accompanied by colonic inflammation. Liver GST activity levels significantly dropped (P < 0.05). Liver COX-2 mRNA expression significantly increased, accompanied by an increase in liver concentrations of PGE2 and TXB2, but no obvious change in 6-K-PGF1alpha concentrations. NS398 and morphine both ameliorated post-stress liver GST activity (P < 0.05 and P < 0.01 respectively), decreased stress-induced COX-2 expression, decreased PGE2 and TXB2 production, but increased liver 6-K-PGF1alpha levels. Morphine attenuation in colonic tissue inflammation was apparent at 24 hours (P < 0.05).</p><p><b>CONCLUSIONS</b>Acute colitis visceral pain liver stress can induce liver injury. Liver injury might have occurred through the activation of the COX-2/prostanoid pathway and increased production of PGE2 and TXB2. Effective analgesia might offer protective effect during visceral pain stress.</p>