PGE2 Content Research Articles

Geochemistry of the Kalatongke Ni–Cu–(PGE) sulfide deposit, NW China: implications for the formation of magmatic sulfide mineralization in a postcollisional environment

The Kalatongke (also spelt as Karatungk) Ni–Cu–(platinum-group element, PGE) sulfide deposit, containing 33 Mt sulfide ore with a grade of 0.8 wt.% Ni and 1.3 wt.% Cu, is located in the Eastern Junggar terrane, Northern Xinjiang, NW China. The largest sulfide ore body, which occupies more than 50 vol.% of the intrusion Y1, is dominantly comprised of disseminated sulfide with a massive sulfide inner zone. Economic disseminated sulfides also occur at the base of the intrusions Y2 and Y3. The main host rock types are norite in the lower part and diorite in the upper part of each intrusion. Enrichment in large ion lithophile elements and depletion in heavy rare earth elements relative to mid-ocean ridge basalt indicate that the mafic intrusions were produced from magmas derived from a metasomatized garnet lherzolite mantle. The average grades of the disseminated ores are 0.6 wt.% Ni and 1.1 wt.% Cu, whereas those of the massive ores are 2 wt.% Ni and 8 wt.% Cu. The PGE contents of the disseminated ores (14–69 ppb Pt and 78–162 ppb Pd) are lower than those of the massive ores (120–505 ppb Pt and 30–827 ppb Pd). However, on the basis of 100% sulfide, PGE contents of the massive sulfides are lower than those of the disseminated sulfides. Very high Cu/Pd ratios (>4.5 × 104) indicate that the Kalatongke sulfides segregated from PGE-depleted magma produced by prior sulfide saturation and separation. A negative correlation between the Cu/Pd ratio and the Pd content in 100% sulfide indicates that the PGE content of the sulfide is controlled by both the PGE concentrations in the parental silicate magma and the ratio of the amount of silicate to sulfide magma. The negative correlations between Ir and Pd indicate that the massive sulfides experienced fractionation.

Prostaglandin E receptor subtype EP3 in conjunctival epithelium regulates late-phase reaction of experimental allergic conjunctivitis

We previously demonstrated that the prostaglandin E(2) (PGE(2))-EP3 pathway negatively regulates allergic reactions in a murine allergic asthma model. We investigated whether the PGE(2)-EP3 pathway also regulates the development of murine experimental allergic conjunctivitis (EAC). The expression of EP3 was examined by means of RT-PCR and immunohistochemistry in wild-type mice, as well as by means of 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside staining in mice deficient in EP3 (Ptger3(-/-) mice) carrying the beta-galactosidase gene at the EP3 gene locus. EAC was induced by immunization of mice with short ragweed pollen (RW), followed by challenge with eye drops of RW, and eosinophil infiltration and eotaxin-1 mRNA expression in the conjunctiva were examined. Mice were also treated with a topical application of an EP3-selective agonist during the elicitation phase. Quantitative RT-PCR was used to detect expression of COXs and prostaglandin E synthases, and ELISA was used to measure PGE(2) production in the eyelid. EP3 was constitutively expressed in conjunctival epithelium on the ocular surface. Ptger3(-/-) mice demonstrated significantly increased eosinophil infiltration in conjunctiva after RW challenge compared with wild-type mice. Consistently, significantly higher expression of eotaxin-1 mRNA was observed in Ptger3(-/-) mice. Conversely, treatment of wild-type mice with an EP3-selective agonist resulted in a significant decrease in eosinophil infiltration, which was blunted in Ptger3(-/-) mice. Expression of COX-2 and prostaglandin E synthases was upregulated and PGE(2) content was increased in the eyelids after RW challenge. These data suggest that PGE(2) acts on EP3 in conjunctival epithelium and downregulates the progression of EAC.

Immobilization and controlled release of prostaglandin E2 from poly‐L‐lactide‐co‐glycolide microspheres

Prostaglandin E(2) (PGE(2)) is an arachidonic acid metabolite involved in physiological homeostasis and numerous pathophysiological conditions. Furthermore, it has been demonstrated that prostaglandins have a stimulating effect not only on angiogenesis in situ and in vitro but also on chondrocyte proliferation in vitro. Thus, PGE(2) represents an interesting signaling molecule for various tissue engineering strategies. However, under physiological conditions, PGE(2) has a half-life time of only 10 min, which limits its use in biomedical applications. In the present study, we investigated if the incorporation of PGE(2) into biodegradable poly-L-lactide-co-glycolide microspheres results in a prolonged release of this molecule in its active form. PGE(2)-modified microspheres were produced by a cosolvent emulsification method using CHCl(3) and HFIP as organic solvents and PVA as emulsifier. Thirteen identical batches were produced; and to each batch 1.0 mL of serum-free medium was added. The medium was removed at defined time points and then analyzed by gas chromatography tandem mass spectrometry (GC/MS/MS) to measure the residual PGE(2) content. In this study we demonstrated the prolonged release of PGE(2), showing a linear increase over the first 12 h, followed by a plateau and a slow decrease. The microspheres were further characterized by scanning electron microscopy.

Phosphodiesterase Isozymes Involved in Regulation of Secretion in Isolated Mouse Stomach in Vitro

(+/-)-(E)-4-Ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide] (NOR-3), a nitric-oxide (NO) donor, is known to increase HCO(3)(-) secretion in rat stomachs, intracellularly mediated by cGMP; yet, there is no information about the phosphodiesterase (PDE) isozyme involved in this process. We examined the effects of various isozyme-selective PDE inhibitors on the secretion of HCO(3)(-) in the mouse stomach in vitro and the type(s) of PDE isozymes involved in the response to NO. The gastric mucosa of DDY mice was stripped of the muscle layer and mounted on an Ussing chamber. HCO(3)(-) secretion was measured at pH 7.0 using a pH-stat method and by adding 2 mM HCl. NOR-3, 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP), and various PDE inhibitors were added to the serosal side. Vinpocetine (PDE1 inhibitor) or zaprinast (PDE5 inhibitor) was also added serosally 30 min before NOR-3 or 8-Br-cGMP. Both NOR-3 and 8-Br-cGMP stimulated HCO(3)(-) secretion in a dose-dependent manner, and the response to NOR-3 was significantly inhibited by methylene blue. Likewise, the secretion induced by NOR-3 or 8-Br-cGMP was significantly attenuated by 6-((2S,3S)-3-(4-chloro-2-methylphenylsulfonylaminomethyl)-bicyclo(2.2.2)octan-2-yl)-5Z-hexenoic acid (ONO-8711), the PGE receptor (EP)1 antagonist, as well as indomethacin and potentiated by both vinpocetine and zaprinast at doses that had no effect by themselves on the basal secretion, whereas other subtype-selective PDE inhibitors had no effect. NOR-3 increased the mucosal PGE(2) content in a methylene blue-inhibitable manner. These results suggest that NO stimulates gastric HCO(3)(-) secretion mediated intracellularly by cGMP and modified by both PDE1 and PDE5, and this response is finally mediated by endogenous PGE(2) via the activation of EP1 receptors.

7β-Hydroxy-epiandrosterone-mediated regulation of the prostaglandin synthesis pathway in human peripheral blood monocytes

7α-Hydroxy-DHEA, 7β-hydroxy-DHEA and 7β-hydroxy-EpiA are native metabolites of dehydroepiandrosterone (DHEA) and epiandrosterone (EpiA). Since numerous steroids are reported to interfere with inflammatory and immune processes, our objective was to test the effects of these hydroxysteroids on prostaglandin (PG) production and related enzyme gene expression. Human peripheral blood monocytes were cultured for 4 and 24 h in the presence of each of the steroids (1–100 nM), with and without addition of TNF-α (10 ng/mL). Levels of PGE 2, PGD 2 and 15-deoxy-Δ 12,14-PGJ 2 (15d-PGJ 2) were measured in the incubation medium, and cell content of cyclooxygenase (COX-2), and PGE and PGD synthases (m-PGES1, H-PGDS, L-PGDS), and peroxisome proliferator activated receptor (PPAR-γ) was assessed by quantitative RT-PCR and Western blots. Addition of TNF-α resulted in elevated PG production and increased COX-2 and m-PGES1 levels. Among the three steroids tested, only 7β-hydroxy-EpiA decreased COX-2, m-PGES1 and PPAR-γ expression while markedly decreasing PGE 2 and increasing 15d-PGJ 2 production. These results suggest that 7β-hydroxy-EpiA is a native trigger of cellular protection through simultaneous activation of 15d-PGJ 2 and depression of PGE 2 synthesis, and that these effects may be mediated by activation of a putative receptor, specific for 7β-hydroxy-EpiA.

Growth associated proteins in tumor cells and stroma related to disease progression of colon cancer accounting for tumor tissue PGE2 content

Connections among specific proteins (Bax, Bcl-2, bFGF, COX-1, COX-2, E-cad, p15, p53, PCNA, TGFbeta3, TUNEL, vWF) in control of cell proliferation, apoptosis, cell adhesion, tumor vascularity and PGE2 content were evaluated in colon cancer as related to disease progression and survival. Tumor tissue and adjacent normal colon mucosa were obtained at curative resection in 22 patients. PGE2 concentrations were assessed in tumor tissue and tumor derived blood, splanchnic blood, peripheral venous blood and urine. Host inflammation was determined (CRP, ESR) in relationship to tumor differentiation and stage. Patients survived as expected according to Dukes A-D staging. Growth-related proteins correlated between tumor cells and stroma as well as between protein factors within tumor cells and tumor stroma. COX-2 predicted tumor tissue content of PGE2 (p<0.002), without reflection in tumor derived blood. Systemic inflammation was predicted by p15, TGFbeta3 and Bcl-2 in tumor tissue (p<0.001). p15 and vWF predicted reduced survival in ungrouped patients (p<0.02), while p15, PCNA, TGFbeta3 and vWF predicted reduced survival (p<0.0001) when patient grouping accounted for high tumor content of PGE2. Our results connect systemic inflammation and survival to COX-2 staining and increased PGE2 in colon cancer. Thus, it seems important to understand proximal signals behind upregulation of COX-2 and subsequent PGE2 production in certain tumor cells in colon cancer.

Effects of ginsenoside and berberine on secretion of immunosuppressive cytokines in lung carcinoma cell line PG

To observe the effects of ginsenoside (Gs) and berberine (Ber), two kinds of active components of traditional Chinese herbal medicine, on transforming growth factor-beta1 (TGF-beta1) and prostaglandin E2 (PGE2) in PG cells. Co-culture system of human lung carcinoma cell line PG and human T lymphocyte cell line Jurkat was established. PG cells were treated with Gs (100 microg/ml) and Ber (10 mug/ml) for twenty-four hours, and then cocultured with Jurkat cells. After 24-hour coculture, the state of Jurkat cells was observed with inverted microscope. The viable count of Jurkat cells was detected by trypan blue staining after 6- and 24-hour coculture, and the apoptosis of Jurkat cells was evaluated by flow cytometry. PG cells were treated with 100, 50, 25 microg/ml Gs and 10, 5, 2.5 microg/ml Ber respectively, and the content of TGF-beta1 and PGE(2) in PG cells was detected by enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA) method. After coculture with PG cells treated with Gs and Ber, the number of Jurkat cells was less than blank control group, and the apoptosis rates of Jurkat cells in Gs- and Ber-treated groups were higher than blank control group. Gs and Ber could promote the secretion of TGF-beta1 in PG cells, but could not change the level of PGE(2). Gs and Ber can promote the growth inhibition and apoptosis of Jurkat cells induced by PG cells, which may be related to the up-regulation of Gs and Ber on TGF-beta1 secretion in PG cells.

The influence of embryo presence on prostaglandins synthesis and prostaglandin E2 and F2α content in corpora lutea during periimplantation period in the pig

We determined the expression of PGE2 synthase (mPGES-1), PGF synthase (PGFS), carbonyl reductase/prostaglandin 9-ketoreductase (CBR1) genes and the content of PGE2, PGF2alpha in porcine corpora lutea on Days 12-14 of pregnancy and Days 12-14 of the estrous cycle. For this study we used a surgically-generated model in which one of the uterine horns was cut transversely and a part of this horn was detached from the uterine corpus. The expression of mPGES-1, PGFS, and CBR1 genes and mPGES-1/PGFS ratio were significantly higher in corpora lutea of the pregnant gilts compared to the corpora lutea from the parallel ovaries of the cyclic gilts. There was no difference in mPGES-1, PGFS, CBR1 genes expression and mPGES-1/PGFS ratio between corpora lutea ipsi-(CL1) and contralateral (CL2) to the uterine horn with the developing embryos. The highest content of PGE2 was found in CL1 of the pregnant gilts. The PGE2/PGF2alpha ratio was significantly higher in CL1 of the pregnant gilts compared to corpora lutea from parallel ovary of the cyclic gilts. We suggest that the activity of the investigated genes is induced by compounds of embryonic origin which are not distributed only to the ipsilateral ovary but are transported within the mesometrium to both ovaries in a more systemic manner.

The Coadministration of Paroxetine and Low-Dose Aspirin Synergistically Enhances Gastric Ulcerogenic Risk in Rats

Paroxetine is often coadministered with low-dose aspirin to treat cerebral infarction patients with depression. In order to assess the ulcerogenic risk induced by the coadministration of these drugs, we examined their effects on gastric secretion using the pylorus ligation method and determined the prostaglandin E(2) (PGE(2)) content in the gastric mucosa using enzyme immunoassay (EIA). Paroxetine stimulated the gastric fluid secretion and acid output, dose-dependently, however, it had no effect on the PGE(2) content in the gastric mucosa. Furthermore, exogenous serotonin inhibited both the gastric fluid secretion and the acid output. The coadministration of low-dose aspirin and paroxetine significantly enhanced the gastric fluid secretion and acid output, thus resulting in gastric bleeding, but it hardly affected the PGE(2) content in the gastric mucosa. The stimulation of gastric secretion by the coadministration of low-dose aspirin and paroxetine is therefore considered to play an important role in the development of gastric injuries.

The effects of COX-1 and COX-2 inhibitors on prostaglandin synthesis and the formation of heterotopic bone in a rat model

Traumatic heterotopic ossification (HO) is a common clinical condition associated with various orthopedic procedures that involve injury to soft tissues near bone. In this study, we tested the hypothesis that the prophylactic effects of NSAID's in the treatment of HO are mediated via inhibition of the COX-2 enzyme. Here we describe a rat model that simulates HO in the human that was used to test the above hypothesis. Heterotopic ossification was surgically induced in the quadriceps by injury to the muscle and femoral periosteum and transplantation of donor bone marrow cells containing osteoprogenitors into the site of injury. HO was imaged and quantified by micro-CT scanning of femurs removed from sacrificed animals at 6 weeks post-injury, three-dimensional computer reconstructions of the scanned bones and computer-assisted morphometric analysis. Prostaglandin E(2) (PGE(2)) synthesis was quantified using an enzyme immunoassay system. The effects of a nonselective COX inhibitor or specific inhibitors of COX-1 or COX-2 following oral administration on the content of ectopic bone and PGE(2) were also measured. Micro-CT and histological analyses demonstrated that all of the femurs in operated limbs developed HO in the vastus lateralis muscle belly of the quadriceps close to the anterior femur. Only the COX-1,2 nonselective and COX-2 inhibitors significantly decreased HO formation (by about one-third in each case; P < 0.05). PGE(2) synthesis at the site of injury was increased 50- and 100-fold (to 25 ng/g tissue) within 1 and 7 days, respectively, post-injury with the levels declining to near baseline within 2 weeks of surgery. Both the COX-1,2 nonselective and COX-2 inhibitors significantly decreased PGE(2) levels to 25% of control HO levels within 24 h of the first administration, even at low dosages. The COX-1 inhibitor only produced the same effect after 1 week of administration. These findings suggest that although inhibitors of COX-2 or COX-1 reduced PGE(2) synthesis, only the COX-2 enzyme plays a role in the mechanism of traumatic HO.

Role of β-Adrenergic Receptors in Inflammatory Marker Expression in Müller Cells

To determine whether beta-adrenergic receptors are involved in the modulation of inflammatory cytokines in Müller cells in a hyperglycemic environment. Rat Müller cells were grown in high (25 mM)- or low (5 mM)-glucose medium. Müller cells lysates were processed for real-time polymerase chain reaction to measure steady state mRNA expression for the following inflammatory markers: iNOS, TNF-alpha, IL-1B, and ICAM-1. Western blot analysis and ELISA assays were performed to determine the protein levels of these inflammatory markers and PGE2 content. Isoproterenol treatment significantly decreased protein levels of iNOS, TNF-alpha, and IL-1B, in rMC-1 cells cultured in high glucose as early as 1 hour, compared with cells receiving no treatment. PGE2 content was also reduced after isoproterenol treatment. There were no significant changes observed in protein levels of ICAM-1 production after isoproterenol treatment in high glucose. Steady state mRNA levels for iNOS were significantly decreased 1 hour after isoproterenol, whereas ICAM-1 gene expression was significantly increased after 1 hour. Isoproterenol significantly increased gene expression for IL-1B after 24 hours of treatment. These results suggest that stimulation of beta-adrenergic receptors with isoproterenol leads to decreased levels of PGE(2), TNF-alpha, and IL-1B protein content, and in both gene expression and protein levels of iNOS in Müller cells cultured in hyperglycemia. beta-Adrenergic receptor agonists had limited effects on ICAM-1 protein production. These results indicate that isoproterenol treatment reduces cytokine activation in cultured rat Müller cells.

Stimulatory effect of Coca-ColaTM on gastroduodenal HCO3− secretion in rats

We examined the effect of various carbonated beverages, especially Coca-ColaTM, on the HCO3− secretion in the rat stomach and duodenum. Under urethane anaesthesia, a chambered stomach or a proximal duodenal loop was perfused with saline, and HCO3− secretion was measured at pH 7.0 using a pH-stat method and by adding 2 mM HCl. The amount of CO2 contained in these beverages was about 4–7 g/mL. Coca-ColaTM topically applied to the mucosa for 10 min significantly increased the HCO3− secretion in both the stomach and the duodenum. The HCO3− response in the duodenum was totally abolished by indomethacin and also partially inhibited by acetazolamide, an inhibitor of carbonic anhydrase. Likewise, the response in the stomach was also markedly inhibited by either acetazolamide or indomethacin. The mucosal application of Coca-ColaTM increased the PGE2 contents in both the stomach and the duodenum. Other carbonated beverages, such as sparkling water, Fanta GrapeTM or cider, also increased the HCO3− secretion in these tissues. These results suggest that Coca-ColaTM induces HCO3− secretion in both the stomach and the duodenum, and these responses may be attributable to both the intracellular supply of HCO3− generated via carbonic anhydrase, and endogenous PGs, probably related to the acidic pH of the solution.

Gender-Related Difference in Composition of Secretion from Esophageal Submucosal Mucous Glands, in Response to Stimulation of Serotonergic Pathway, in Patients with Gastroesophageal Reflux Disease

Purpose: Protective potential of saliva and esophageal secretion in gastroesophageal reflux disease (GERD) patients is well established (Sarosiek J. et al., J P Gastroenterol 18: 20J–20Q, 1994). Stimulation of serotonin receptor 5HT-4 with tegaserod augments salivary and esophageal components of pre-epithelial defense in GERD (Majewski et al., CG&H, 5:430–8, 2007). The impact of gender on esophageal secretion in GERD patients during stimulation of 5HT-4 receptor remains to be addressed. Aim: To measure the rate of secretion of esophageal protective factors in females (F) and males (M) with chronic heartburn symptoms after 7 days of tegaserod (6 mg BID) or placebo administration. Methods: The study was conducted in 38 GERD patients (26 F & 12 M; mean age of 41) in a double-blind, placebo-controlled, cross-over design. Esophageal secretion was collected during the sophageal mucosal exposure to baseline NaCl, HCl/pepsin and final NaCl, using the esophageal perfusion catheter. Esophageal volume and its content of bicarbonates, non-bicarbonates, mucin, EGF, TGFα and PGE2 were measured using standard methodology. Results: In females after tegaserod, TGFα secretion during the esophageal mucosal exposure to HCl/pepsin solution increased from 15.0 ± 2.47 to 22.1 ± 2.71 pg/min (46.9%, P < 0.04). In contrast, in males, TGFα decreased by 51.5%, P < 0.03. The rate of esophageal EGF secretion in females during administration of tegaserod increased by 145% (P < 0.01) whereas in males increased by 50% (P > 0.10). The rate of esophageal PGE2 secretion during administration tegaserod increased by 81% (P= 0.076) in females only. Males responded by an evident increase of non-bicarbonates (by 69%) during administration of tegaserod, from 5.29 ± 0.56 to 8.95 ± 1.89 μEq/min (P= 0.08) and increase of bicarbonates by 143% but not females. Conclusion: 1. A significant enhancement of esophageal protective factors after tegaserod in both genders indicates that secretion of esophageal glands in GERD patients is mediated by serotonergic pathway. 2. The gender-related differences in the serotonergic secretory profiles suggest that 5HT-4 receptors in esophageal glands are influenced by sex hormones.

The cardioprotection of the late phase of ischemic preconditioning is enhanced by postconditioning via a COX-2-mediated mechanism in conscious rats

The present study sought to determine whether the combination of late preconditioning (PC) with postconditioning enhances the reduction in infarct size. Chronically instrumented rats were assigned to a 45-min (subset 1) or 60-min (subset 2) coronary occlusion followed by 24 h of reperfusion. In each subset, rats received no further intervention (control) or were preconditioned 24 h before occlusion (PC), postconditioned at the onset of reperfusion following occlusion, or preconditioned and postconditioned without (PC + postconditioning) or with the COX-2 inhibitor celecoxib (3 mg/kg ip; PC + postconditioning + celecoxib) 10 min before postconditioning. Myocardial cyclooxygenase-2 (COX-2) protein expression and COX-2 activity (assessed as myocardial levels of PGE(2)) were measured 6 min after reperfusion in an additional five groups (control, PC, postconditioning, PC + postconditioning, and PC + postconditioning + celecoxib) subjected to a 45-min occlusion. PC alone reduced infarct size after a 45-min occlusion but not after a 60-min occlusion. Postconditioning alone did not reduce infarct size in either setting. However, the combination of late PC and postconditioning resulted in a robust infarct-sparing effect in both settings, suggesting additive cardioprotection. Celecoxib completely abrogated the infarct-sparing effect of the combined interventions in both settings. Late PC increased COX-2 protein expression and PGE(2) content. PGE(2) content (but not COX-2 protein) was further increased by the combination of both interventions, suggesting that postconditioning increases the activity of COX-2 induced by late PC. In conclusion, the combination of late PC and postconditioning produces additive protection, likely due to a postconditioning-induced enhancement of COX-2 activity.

Cyclooxygenase-2/prostaglandin E2 accelerates the healing of gastric ulcers via EP4 receptors

We examined the involvement of cyclooxygenase (COX)-1 as well as COX-2 in the healing of gastric ulcers and investigated which prostaglandin (PG) EP receptor subtype is responsible for the healing-promoting action of PGE2. Male SD rats and C57BL/6 mice, including wild-type, COX-1(-/-), and COX-2(-/-), were used. Gastric ulcers were produced by thermocauterization under ether anesthesia. Gastric ulcer healing was significantly delayed in both rats and mice by indomethacin and rofecoxib but not SC-560 given for 14 days after ulceration. The impaired healing was also observed in COX-2(-/-) but not COX-1(-/-) mice. Mucosal PGE2 content increased after ulceration, and this response was significantly suppressed by indomethacin and rofecoxib but not SC-560. The delayed healing in mice caused by indomethacin was significantly reversed by the coadministration of 11-deoxy-PGE1 (EP3/EP4 agonist) but not other prostanoids, including the EP1, EP2, and EP3 agonists. By contrast, CJ-42794 (selective EP(4) antagonist) significantly delayed the ulcer healing in rats and mice. VEGF expression and angiogenesis were both upregulated in the ulcerated mucosa, and these responses were suppressed by indomethacin, rofocoxib, and CJ-42794. The expression of VEGF in primary rat gastric fibroblasts was increased by PGE2 or AE1-329 (EP4 agonist), and these responses were both attenuated by coadministration of CJ-42794. These results confirmed the importance of COX-2/PGE2 in the healing mechanism of gastric ulcers and further suggested that the healing-promoting action of PGE2 is mediated by the activation of EP4 receptors and is associated with VEGF expression.

Phytonutrient: Effects on Lipid Peroxidation in Experimental Gastritis Induced by Restraint Stress

In this research we studied the effect of free radical scavengers on restraint-induced lesions in rats. Forty rats were divided into 2 equal sized groups; a control group that was given a vitamin E deficient diet and a treatment group that was given the same diet but with oral supplementation of palm-based phytonutrient complex (PPC) at 60 mg kg-1 body weight for 28 days. At the end of the treatment period, half the numbers of rats in each group were sacrificed while the remaining half were subjected to daily restraint-stress for 2 h on 4 consecutive days. The rats were sacrificed after the fourth exposure, their stomach isolated and examined for lesions, gastric PGE2 content, gastric malondialdehyde level and the gastric reduced glutathione level were measured as an index to reflect the scavenging abilities of PPC. Present findings showed hemorrhagic gastric lesions in rat exposed to stress. Rats that received PPC had less gastric lesions compared to the non-stressed control. The malondialdehyde level was also significantly lower in rats given PPC supplementation compared to the control while the reduced glutathione levels were preserved. We conclude that it is indeed probable that oxygen radicals are involved in the pathogenesis of restraint stress-induced lesions thus supplementation with antioxidant such as PPC may be able to reduce or inhibit the formation of these lesions.

Aggravation by Selective COX-1 and COX-2 Inhibitors of Dextran Sulfate Sodium (DSS)-Induced Colon Lesions in Rats

We examined the effect of cyclooxygenase (COX) inhibitors on dextran sulfate sodium (DSS)-induced ulcerative colitis in rats and investigated the role of COX isozymes in the pathogenesis of this model. Experimental colitis was induced by treatment with 2.5% DSS in drinking water for 6 days. Indomethacin (a nonselective COX inhibitor), SC-560 (a selective COX-1 inhibitor), or celecoxib (a selective COX-2 inhibitor) was given PO twice daily for 6 days, during the first 3 or last 3 days of the experimental period. Daily treatment with 2.5% DSS for 6 days caused damage to the colon, with a decrease in body weight gain and colon length as well as an increase of myeloperoxidase (MPO) activity. All COX inhibitors given for 6 days significantly worsened the severity of DSS-induced colonic damage with increased MPO activity. The aggravation was also observed by SC-560 given for the first 3 days or by celecoxib given for the last 3 days. The expression of COX-2 mRNA in the colon was upregulated on day 3 during DSS treatment, with significant increase of prostaglandin E(2) PGE(2) production. The PGE(2) content on day 3 during DSS treatment was inhibited by both indomethacin and SC-560, but not by celecoxib; on day 6 it was suppressed by both indomethacin and celecoxib, but not SC-560. These results suggest that endogenous prostaglandins (PGs) afford protection against colonic ulceration, yet the COX isozyme responsible for the production of PGs differs depending on the stage of ulceration; COX-1 in the early stage and COX-2 in the late stage.

A rabbit model of cervical spondylosis established by stimulation of wind, cold and dampness

To make an animal model of cervical spondylosis (arthralgia syndrome type) with stimulation of wind, cold, and dampness. Twenty-four 8 months old male New Zealand white rabbits were randomly allocated into four groups: normal control group, light stimulation group, moderate stimulation group and severe stimulation group. The wind speed was 10.8-13.8 m/s, the temperature was (5+/-0.5)degrees centigrade, and the humidity was 100%. The rabbits of light, moderate, and severe stimulation groups were kept in the above-mentioned environments for 4 hours everyday, and for a total of 32, 64, and 128 hours, respectively. The intervertebral discs were stained with HE method, and observed with a light microscope. Prostaglandin E(2) (PGE(2)), 6-ketone-prostaglandin F1alpha (6-K-PGF(1alpha)) and thromboxane B(2) (TXB(2)) contents were measured by ELISA. Fas and Bcl-2 expressions were examined by immunohistochemical avidin-biotin peroxidose complex technique. Interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), and transforming growth factor beta (TGF-beta) mRNA expressions were examined by reverse transcription-polymerase chain reaction. The nucleus pulposus of rabbits in the light and moderate stimulation groups shrunken, and in the severe stimulation group, the anulus fibrosus loosed or ruptured, and the cartilage end-plate became proliferated. Compared with rabbits in the normal control group, the PGE(2) content rose in the light stimulation group, the contents of PGE(2), 6-K-PGF(1alpha), and TXB(2) increased, the expressions of IL-1beta and TNF-alpha mRNAs and Fas were up-regulated, and the expressions of TGF-beta mRNA and Bcl-2 were down-regulated in the moderate and severe stimulation groups. The expression of Fas was up-regulated mostly and Bcl-2 was down-regulated mostly in the severe group. Moderate and severe stimulations of wind, cold and dampness can lead to degeneration of cervical intervertebral discs of rabbits. The model corresponds to the theory of traditional Chinese medicine about arthralgia syndrome caused by wind, cold and dampness.

PPARδ and its activator PGI2 are reduced in diabetic embryopathy: involvement of PPARδ activation in lipid metabolic and signalling pathways in rat embryo early organogenesis

Maternal diabetes significantly increases the risk of congenital malformations, and the mechanisms involved are not yet clarified. This study was designed to address peroxisome proliferator-activated receptor delta (PPARdelta) involvement in diabetic embryopathy. We investigated the concentrations of PPARdelta and its endogenous agonist prostaglandin (PG)I(2), as well as the effect of PPARdelta activation on lipid metabolism and PGE(2) concentrations in embryos from control and streptozotocin-induced diabetic rats during early organogenesis. Embryos from diabetic rats showed decreased concentrations of PPARdelta and its endogenous agonist PGI(2) when compared with controls. In embryos from control rats, the addition of the PPARdelta activators (cPGI(2) and PGA(1)) increased embryonic phospholipid levels and de novo phospholipid synthesis studied using (14)C-acetate as a tracer. PGE(2) formed from arachidonate released from phospholipid stores was also up-regulated by PPARdelta activators. In embryos from diabetic rats, reduced phospholipid synthesis and PGE(2) content were observed, and clearly up-regulated by cPGI(2) additions to values similar to those found in control embryos. These data suggest that PPARdelta may play an important role in lipid metabolic and signalling pathways during embryo organogenesis, developmental pathways that are altered in embryos from diabetic rats, possibly as a result of a reduction in levels of PPARdelta and its endogenous activator PGI(2).

Cyclooxygenase-1 Overexpression Decreases Basal Airway Responsiveness but Not Allergic Inflammation

Pharmacological inhibition or genetic disruption of cyclooxygenase (COX)-1 or COX-2 exacerbates the inflammatory and functional responses of the lung to environmentally relevant stimuli. To further examine the contribution of COX-derived eicosanoids to basal lung function and to allergic lung inflammation, transgenic (Tr) mice were generated in which overexpression of human COX-1 was targeted to airway epithelium. Although no differences in basal respiratory or lung mechanical parameters were observed, COX-1 Tr mice had increased bronchoalveolar lavage fluid PGE(2) content compared with wild-type littermates (23.0 +/- 3.6 vs 8.4 +/- 1.4 pg/ml; p < 0.05) and exhibited decreased airway responsiveness to inhaled methacholine. In an OVA-induced allergic airway inflammation model, comparable up-regulation of COX-2 protein was observed in the lungs of allergic wild-type and COX-1 Tr mice. Furthermore, no genotype differences were observed in allergic mice in total cell number, eosinophil content (70 vs 76% of total cells, respectively), and inflammatory cytokine content of bronchoalveolar lavage fluid, or in airway responsiveness to inhaled methacholine (p > 0.05). To eliminate the presumed confounding effects of COX-2 up-regulation, COX-1 Tr mice were bred into a COX-2 null background. In these mice, the presence of the COX-1 transgene did not alter allergen-induced inflammation but significantly attenuated allergen-induced airway hyperresponsiveness, coincident with reduced airway leukotriene levels. Collectively, these data indicate that COX-1 overexpression attenuates airway responsiveness under basal conditions but does not influence allergic airway inflammation.