Relationship of cyclic stretching of human patellar tendon fibroblasts with abnormal increase of prostaglandins E2 and leukotriene B4

To investigate the relationship between tendinopathy and higher production of prostaglandins E2 (PGE2) and leukotriene B4(LTB4) induced by cyclic stretching of human patellar tendon fibroblasts.Methods We used a novel in vitro model system to mimic in vivo conditions,where human patellar tendon fibroblasts (HPTFs) were uniaxially stretched with different magnitudes of stretching (4%,8% and 12%).Non-stretched fibroblasts were used as control.The productions of PGE2 and LTB4 as well as the expression of cycloxygenase (COX) and 5-lipoxygenase (5-LO) were then measured every four hours of cyclic stretching.In addition,we treated the cells with inhibitors of COX or 5-LO.Results It was found that cyclic stretching of fibroblasts at 8% and 12% of stretching increased PGE2 and LTB4 levels.Blocking the COX enzyme with indomethacin (25 mol/L) decreased PGE2 levels but increased LTB4 production and vice versa.Whereas decreasing LTB4 production with MK-886 (10 μmol/L) could increase PGE2 levels compared to cells tretched without inhibitors.Conclusion Cyclic stretching of HPTFs produces high levels of PGE2 and LTB4,where a balance exists:blocking PGE2 production increases the production of LTB4,and vice versa.Therefore,this study raises the possibility that the routine use of COX inhibitors in clinical treatment of tendinopathy may exacerbate the condition by causing neutrophil-mediated inflammatory and degenerative changes in the tendon due to increased levels of LTB4,which is a potent chemoattractant for neutrophils.17 refs,3 figs.

Pathogenesis of chronic enteropathy associated with the SLCO2A1 gene:Hypotheses and conundrums

Chronic enteropathy associated with the SLCO2A1 gene(CEAS)is a complex gastroenterological condition characterized by multiple ulcers in the small intestine with chronic bleeding and protein loss.This review explores the potential mechanisms underlying the pathogenesis of CEAS,focusing on the role of SLCO2A1-encoded prostaglandin transporter OATP2A1 and its impact on prostaglandin E2(PGE2)levels.Studies have suggested that elevated PGE2 levels contribute to mucosal damage,inflammation,and disruption of the intestinal barrier.The effects of PGE2 on macrophage activation and Maxi-Cl channel functionality,as well as its interaction with nonsteroidal anti-inflammatory drugs play crucial roles in the progression of CEAS.Understanding the balance between its protective and pro-inflammatory effects and the complex interactions within the gastrointestinal tract can shed light on potential therapeutic targets for CEAS and guide the development of novel,targeted therapies.

Intra-arterial lipo-prostaglandin E1 infusion for arterial spasm in liver transplantation:A case report

BACKGROUND Hepatic artery obstruction is a critical consideration in graft outcomes after living donor liver transplantation.We report a case of diffuse arterial vasospasm that developed immediately after anastomosis and was managed with an intra-arterial infusion of lipo-prostaglandin E1(PGE1).CASE SUMMARY A 57-year-old male with hepatitis B virus-related liver cirrhosis and hepatocellular carcinoma underwent ABO-incompatible living donor liver transplant.The grafted hepatic artery was first anastomosed to the recipient’s right hepatic artery stump.However,the arterial pulse immediately weakened.Although a new anastomosis was performed using the right gastroepiploic artery,the patient’s arterial pulse rate remained poor.We attempted angiographic intervention immediately after the operation;it showed diffuse arterial vasospasms like‘beads on a string’.We attempted continuous infusion of lipo-PGE1 overnight via an intra-arterial catheter.The next day,arterial flow improved without any spasms or strictures.The patient had no additional arterial complications or related sequelae at the time of writing,1-year post-liver transplantation.CONCLUSION Angiographic evaluation is helpful in cases of repetitive arterial obstruction,and intra-arterial infusion of lipo-PGE1 may be effective in treating diffuse arterial spasms.

前列腺素E1对原发性肾病综合征作用初探(英文)

Objective:To investigate the effect of prostaglandin E1 (PGE1) (Alprostadii injection) on patients with primary nephrotic syndrome(PNS). Methods: 37 patients with PNS were recruited to study the effect of prostaglandin E1 on platelet aggregation function [ PAG (5,) PAG( m ) ], serum total protein (TP) , albumin (Al),blood urea nitrogen(BUN) ,serum creatinine(Scr) ,cholesterol(CHO), triglyceride(TG), protein in 24-hour urine (Pr/24h) and platelet account (PLT). Results: TP, Al, CHO, TG, BUN, Scr, Pr/24h, PAG(5) and PAG(m) in PNS group before treatment were significantly different from those in control group(P＜0.05, P＜0.01) while no significant difference was found for PLT. When treated with PGE1 , TP,Al,CHO, TG, Pr/24h, ADP- induced PAG(5) ,and Adr- induced PAG(5) and PAG(m) were significantly different from those before treatment (P＜0.05). Adr- induced PAG(5) and PAG(m) were significantly different. Adr- induced PAG(5) was xsitively correlated with BUN and Scr in PNS(P＜0.01). Similar correlation was found between ADP-induced PAG(5) and Al ,BUN,Scr,Pr/24h(P＜0.05), AD- induced PAG(m) and TP,CHO(P＜0.05). Conclusions: PGE1 may be an effective drug for the treatment for hypercoagulation in patients with PNS.

Genetic variant of cyclooxygenase-2 in gastric cancer:More inflammation and susceptibility

Gastric cancer accounts for the majority cancer-related deaths worldwide.Although various methods have considerably improved the screening,diagnosis,and treatment of gastric cancer,its incidence is still high in Asia,and the 5-year survival rate of advanced gastric cancer patients is only 10%-20%.Therefore,more effective drugs and better screening strategies are needed for reducing the incidence and mortality of gastric cancer.Cyclooxygenase-2(COX-2)is considered to be the key inducible enzyme in prostaglandins(PGs)synthesis,which is involved in multiple pathways in the inflammatory response.For example,inflammatory cytokines stimulate innate immune responses via Toll-like receptors and nuclear factor-kappa B to induce COX-2/PGE2 pathway.In these processes,the production of an inflammatory microenvironment promotes the occurrence of gastric cancer.Epidemiological studies have also indicated that non-steroidal antiinflammatory drugs can reduce the risk of malignant tumors of the digestive system by blocking the effect of COX-2.However,clinical use of COX-2 inhibitors to prevent or treat gastric cancer may be limited because of potential side effects,especially in the cardiovascular system.Given these side effects and low treatment efficacy,new therapeutic approaches and early screening strategies are urgently needed.Some studies have shown that genetic variation in COX-2 also play an important role in carcinogenesis.However,the genetic variation analysis in these studies is incomplete and isolated,pointing out only a few single nucleotide polymorphisms(SNPs)and the risk of gastric cancer,and no comprehensive study covering the whole gene region has been carried out.In addition,copy number variation(CNV)is not mentioned.In this review,we summarize the SNPs in the whole COX-2 gene sequence,including exons,introns,and both the 5’and 3’untranslated regions.Results suggest that COX-2 does not increase its expression through the CNV and the SNPs in COX-2 may serve as the potential marker to establish risk stratification in the general population.This review synthesizes emerging insights of COX-2 as a biomarker in multiple studies,summarizes the association between whole COX-2 sequence variation and susceptibility to gastric cancer,and discusses the future prospect of therapeutic intervention,which will be helpful for early screening and further research to find new approaches to gastric cancer treatment.

Celecoxib Inhibits Proliferation and Induces Apoptosis via Cyclooxygenase-2 Pathway in Human Pancreatic Carcinoma Cells

In order to evaluate the effects and mechanisms of celecoxib in inhibiting proliferation and inducing apoptosis on human pancreatic carcinoma cells, the anti-proliferative effect was measured by using methabenzthiazuron (MTT) assay. Cell cycle and apoptosis were analyzed by using flow cytometry (FCM), and the PGE 2 levels in the supernatant of cultured pancreatic carcinoma cells were quantitated by enzyme-linked immunoabsordent assay (ELISA). Our results showed that celecoxib suppressed the production of PGE 2 and inhibited the growth of JF-305 cells, and the anti-proliferative effect of celecoxib could be abolished by addition of PGE 2. FCM revealed that celecoxib could inhibit proliferation and induce apoptosis by G 1-S cell cycle arrest. It was concluded that cyclooxygenase-2 specific inhibitor celecoxib could inhibit proliferation and induced apoptosis of human pancreatic carcinoma cells via suppression of PGE 2 production in vitro.

The oral commensal Streptococcus mitis activates the aryl hydrocarbon receptor in human oral epithelial cells

Streptococcus mitis （S. mitis） is a pioneer commensal bacterial species colonizing many of the surfaces of the oral cavity in healthy individuals. Yet, not much information is available regarding its interaction with the host. We used examination of its transcriptional regulation in oral keratinocytes to elucidate some of its potential roles in the oral cavity. Transcription factor analysis of oral keratinocytes predicted S. mitis.mediated activation of aryl hydrocarbon receptor （AhR）, Activation and functionality of AhR was confirmed through nuclear translocation determined by immunofluorescence microscopy and real-time polymerase chain reaction with reverse transcription analysis of CYPIA1, the hallmark gene for AhR activation. Addition of Streptococcus mutans or Streptococcus gordonfi did not induce CYPIA1 transcription in the keratinocyte cultures. Introduction of an AhR-specific inhibitor revealed that S. mitis-mediated transcription of CXCL2 and CXCL8 was regulated by AhR. Elevated levels of pmstaglandin E2 （enzyme-linked immunosorbent assay） in supernatants from S. mitis-treated oral epithelial cells were also attenuated by inhibition of AhR activity. The observed AhR-regulated activities point to a contribution of S. mitis in the regulation of inflammatory responses and thereby to wound healing in the oral cavity. The concept that the oral commensal microbiota can induce AhR activation is important, also in view of the role that AhR has in modulation of T-cell differentiation and as an anti-inflammatory factor in macrophaees.

mPGES-1 expression in non-cancerous liver tissue impacts on postoperative recurrence of HCC

AIM:To investigate whether microsomal prostaglandin E synthase-1 (mPGES-1) expression in hepatocellular carcinoma (HCC) and in non-cancerous liver affects HCC prognosis after hepatectomy. METHODS: The relationship between patient clinical prof iles, tumor factors, surgical determinants, and mPGES-1 expression and the recurrence-free survival rate were examined in 64 patients who underwent curative hepatectomy between March 2003 and December 2006. RESULTS: The scores for mPGES-1 expression were higher in well differentiated and moderately differentiated HCC tissues than in poorly differentiated HCC tissues (well differentiated, 5.1 ± 2.7; moderately differentiated, 5.1 ± 1.7; poorly differentiated, 3.0 ± 1.8). In noncancerous liver tissues, the mPGES-1 levels were higher in injured liver tissues than in normal tissues. Cirrhotic livers had higher mPGES-1 levels than livers with chronic hepatitis (normal livers, 3.3 ± 0.7; chronic hepatitic livers, 5.4 ± 1.9; cirrhotic livers, 6.4 ± 1.6). A univariate analysis revealed that the recurrence-free survival rate was signif icantly lower in patients with vascular invasion,a higher mPGES-1 level in non-cancerous liver tissue,a larger tumor diameter (≥5 cm), and a lower serum albumin level (≤3.7 g/dL). The mPGES-1 expression in HCC tissues did not correlate well with postoperative recurrence. A multivariate analysis demonstrated that the presence of vascular invasion and higher mPGES-1 levels were statistically significant independent predictors for early postoperative recurrence of HCC.CONCLUSION: Increased mPGES-1 expression in noncancerous liver tissues is closely associated with the early recurrence of HCC after curative resection.

Effects of prostaglandin E combined with continuous renal replacement therapy on septic acute kidney injury

BACKGROUND The effects of prostaglandin E(PGE)combined with continuous renal replacement therapy(CRRT)on renal function and inflammatory responses in patients with septic acute kidney injury(SAKI)remain unclear.AIM To investigate the effects of PGE combined with CRRT on urinary augmenter of liver regeneration(ALR),urinary Na+/H+exchanger 3(NHE3),and serum inflammatory cytokines in patients with SAKI.METHODS The clinical data of 114 patients with SAKI admitted to Yichang Second People's Hospital from May 2017 to January 2019 were collected.Fifty-three cases treated by CRRT alone were included in a control group,while the other 61 cases treated with PGE combined with CRRT were included in an experimental group.Their urinary ALR,urinary NHE3,serum inflammatory cytokines,renal function indices,and immune function indices were detected.Changes in disease recovery and the incidence of adverse reactions were observed.The 28-d survival curve was plotted.RESULTS Before treatment,urinary ALR,urinary NHE3,blood urea nitrogen(BUN),serum creatinine(SCr),CD3+T lymphocytes,CD4+T lymphocytes,and CD4+/CD8+T lymphocyte ratio in the control and experimental groups were approximately the same.After treatment,urinary ALR and NHE3 decreased,while BUN,SCr,CD3+T lymphocytes,CD4+T lymphocytes,and CD4+/CD8+T lymphocyte ratio increased in all subjects.Urinary ALR,urinary NHE3,BUN,and SCr in the experimental group were significantly lower than those in the control group,while CD3+T lymphocytes,CD4+T lymphocytes,and CD4+/CD8+T lymphocyte ratio were significantly higher than those in the control group(P<0.05).After treatment,the levels of tumor necrosis factor-α,interleukin-18,and high sensitivity C-reactive protein in the experimental group were significantly lower than those in the control group(P<0.05).The time for urine volume recovery and intensive care unit treatment in the experimental group was significantly shorter than that in the control group(P<0.05),although there was no statistically significant difference in hospital stays between the two groups.The total incidence of adverse reactions did not differ statistically between the two groups.The 28-d survival rate in the experimental group(80.33%)was significantly higher than that in the control group(66.04%).CONCLUSION PGE combined with CRRT is clinically effective for treating SAKI,and the combination therapy can significantly improve renal function and reduce inflammatory responses.

Amentoflavone protects hippocampal neurons: anti-inflammatory, antioxidative, and antiapoptotic effects

Amentoflavone is a natural biflavone compound with many biological properties, including anti-inflammatory, antioxidative, and neuroprotective effects. We presumed that amentoflavone exerts a neuroprotective effect in epilepsy models. Prior to model establishment, mice were intragastrically administered 25 mg/kg amentoflavone for 3 consecutive days. Amentoflavone effectively prevented pilocarpine-induced epilepsy in a mouse kindling model, suppressed nuclear factor-κB activation and expression, inhibited excessive discharge of hippocampal neurons resulting in a reduction in epileptic seizures, shortened attack time, and diminished loss and apoptosis of hippocampal neurons. Results suggested that amentoflavone protected hippocampal neurons in epilepsy mice via anti-inflammation, antioxidation, and antiapoptosis, and then effectively prevented the occurrence of seizures.

B-1 cells modulate the murine macrophage response to Leishmania major infection

AIM To investigate the modulatory effect of B-1 cells on murine peritoneal macrophages infected with Leishmania major(L. major) in vitro.METHODS Peritoneal macrophages obtained from BALB/c andBALB/c XID mice were infected with L. major and cultured in the presence or absence of B-1 cells obtained from wild-type BALB/c mice. Intracellular amastigotes were counted, and interleukin-10(IL-10) production was quantified in the cellular supernatants using an enzymelinked immunosorbent assay. The levels of the lipid mediator prostaglandin E2(PGE2) were determined using a PGE2 enzyme immunoassay kit(Cayman Chemical, Ann Arbor, MI), and the number of lipid bodies was quantified in the cytoplasm of infected macrophages in the presence and absence of B-1 cells. Culturing the cells with selective PGE2-neutralizing drugs inhibited PGE2 production and confirmed the role of this lipid mediator in IL-10 production. In contrast, we demonstrated that B-1 cells derived from IL-10 KO mice did not favor the intracellular growth of L. major.RESULTS We report that B-1 cells promote the growth of L. major amastigotes inside peritoneal murine macrophages. We demonstrated that the modulatory effect was independent of physical contact between the cells, suggesting that soluble factor(s) were released into the cultures. We demonstrated in our co-culture system that B-1 cells trigger IL-10 production by L. major-infected macrophages. Furthermore, the increased secretion of IL-10 was attributed to the presence of the lipid mediator PGE2 in supernatants of L. major-infected macrophages. The presence of B-1 cells also favors the production of lipid bodies by infected macrophages. In contrast, we failed to obtain the same effect on parasite replication inside L. major-infected macrophages when the B-1 cells were isolated from IL-10 knockout mice. CONCLUSION Our results show that elevated levels of PGE2 and IL-10 produced by B-1 cells increase L. major growth, as indicated by the number of parasites in cell cultures.

Anti-inflammatory effect of Heliotropium indicum Linn on lipopolysaccharide-induced uveitis in New Zealand white rabbits

AIM： To investigate the anti-inflammatory effect of an aqueous whole plant extract of Heliotropium indicum（HIE） on endotoxin-induced uveitis in New Zealand white rabbits.·METHODS： Clinical signs of uveitis including flares,iris hyperemia and miosis, were sought for and scored in1.0 mg/kg lipopolysaccharide（LPS）-induced uveitic rabbits treated orally with HIE（30-300 mg/kg）,prednisolone（30 mg/kg）, or normal saline（10 m L/kg）. The number of polymorphonuclear neutrophils infiltrating, the protein concentration, as well as levels of tumor necrosis factor-α（TNF-α）, prostaglandin E2（PGE2）, and monocyte chemmoattrant protein-1（MCP-1） in the aqueous humor after the various treatments were also determined. A histopathological study of the anterior uveal was performed.· RESULTS： The extract and prednisolone-treatment significantly reduced（P ≤0.001） both the clinical scores of inflammation（1.0-1.8 compared to 4.40 ±0.40 in the normal saline-treated rabbits） and inflammatory cells infiltration. The level of protein, and the concentrationsof TNF-α, PGE2 and MCP-1 in the aqueous humor were also significantly reduced（P ≤0.001）. Histopathological studies showed normal uveal morphology in the HIE and prednisolone-treated rabbits while normal saline-treated rabbits showed marked infiltration of inflammatory cells.· CONCLUSION： The HIE exhibits anti-inflammatory effect on LPS-induced uveitis possibly by reducing the production of pro-inflammatory mediators.

Protective effects of prostaglandin E1 perfusion againstspinal cord ischemia-reperfusion injury in a rabbit model

BACKGROUND： Prostaglandin E1 （PGE1） is known to be protective in ischemia-reperfusion of heart, lung,renal, and liver tissue. It still remains to be determined whether PGE1 exhibits similar protection against spinal cord ischemia-reperfusion injury in a rabbit model. OBJECTIVE： To observe the large, ventral horn, motor neurons of the spinal cord, as well as limb function, and to investigate whether perfusion of PGE1 exhibits protective effects against spinal cord ischemia-reperfusion injury in a rabbit model. DESIGN, TIME AND SETTING： Controlled observation. The experiment was performed at the Department of Orthopedics, First Affiliated Hospital of Liaoning Medical University between June and October 2007. MATERIALS： Twenty male, New Zealand white rabbits, weighing 2.0 kg and of mixed gender, were used in the present study. The following chemicals and compounds were used： prostaglandin E1 injectable powder,as well as malondialdehyde and ATPase kits. Animal intervention was in accordance with animal ethical standards. METHODS： We separated rabbits into control and experimental groups randomly, with 10 rabbits in each group. Rabbits were used as spinal cord ischemia models by segmentally cross-clamping the infrarenal aorta. The control group was subsequently perfused for five minutes with blood and saline solution, and the experimental group was perfused for 5 minutes with blood and saline solution containing PGE1 （100 ng/kg/min）. MAIN OUTCOME MEASURES： The neurological function of the hind limbs was assessed 12, 24, and 48 hours after model establishment. All animals were sacrificed and spinal cords were harvested for histological analyses. The large motor neurons in the ventral horn of L1-7 were observed by inverted microscope. RESULTS： All 20 rabbits were included in the final analysis, without any loss. In the ventral horn of the L5-7 segments, there were more large motor neurons that appeared viable in the experimental group than the control group （P 〈 0.05）. The scores of hind limb functions were greater in the experimental group after 12, 24, and 48 hours （P 〈 0.01）. CONCLUSION： Perfusion of PGE1 reduced the amount of neuronal damage in the spinal cord ischemia-reperfusion injury rabbit model. These results correlated with increased numbers large motor neurons in the ventral horn of the spinal cord, as well as improved hind limb function.

Inhibitory Effects of Tetandrine on Experimental Anterior Uveitis Rabbits

Anterior uveitis was induced by injection of lens protein into anterior chamber of rabbit eye.Tetrandrine (Tet) (50mg/kg ip) showed marked inhibition on this ocular inflammation, the total content of prostaglandin E in irises, and leukocyte chemotaxis.The pathological examination revealed that inflammation of irises in Tet group was lighter than that in control group. The antiinflammatory mechanism of Tet may be related to reduction of intracellular free calcium and inhibition of synthesis of inflmmatory factor.

Effect of HDL and apo AI on PGE_2 Production by Monocyte-Derived Macrophages

Effect of antiatherogenic high density lipoprotein (HDL) and apolipoprotein AI (apo AI) on production of prostaglandin E2 (PGE2 ) by human m onocyte- derived macrophages was investigated.Macrophages were loaded with acetylated low density lipoprotein followed by incuba- tion with HDL3or apo AI.PGE2 produced and secreted in culture supernatant was quantified by en- zyme im munoassay.HDL3induced production of PGE2 by m acrophages in a time- dependent m an- ner.2 4 h after incubation,PGE2 production by HDL3- treated macrophages increased 3.7- fold of that by control cells.Apo AI also induced PGE2 secretion to 2 .1- fold,which was significantly less than HDL3.The data indicate that both HDL3and lipid- free apo AI enhance PGE2 synthesis and se- cretion by hum an m acrophages and this may further contribute to the protection from atheroscle- rosis.

The effect of prostaglandin E_1 on recovery of early renal graft functions after transplantation

Objective To investigate the effect of prostaglandin E1 (PGE1) on recovery of early renal graft functions after transplantation. Methods One hundred and seven patients after renal transplantation were allocated in the treated group, and treated by conventional treatment with injection of 10 μg prostaglandin E1 additionally twice a day for 14 days. And eighty-eight patients who received conventional treatment alone after renal transplantation at the corresponding period were allocated in the control group. Indexes of the two groups, including incidence of delayed graft function and acute rejection reaction, volume of urine, serum certaintie (SCr), endogenous certainties clearance rate (CCr), the blood flow resistance in graft as well as blood viscosity (BV), and platelet aggregation rate (PAR), were determined. Results The urinary volume and endogenous certainties clearance rate of the treated group were significantly higher, but the level of SCr, incidence of renal function recovery retardation, BV, PAR and blood flow resistance in graft were significantly lower than those of the control group (P<0.05). The difference of incidence of acute rejection reaction between the two groups was insignificant (P>0.05). Conclusion Prostaglandin E1 can improve blood microcirculation and decrease the incidence of renal function recovery retardation. These effects are helpful for recovery of renal function after renal transplantation.

Expression of prostaglandin E_2 receptors in rat hippocampus

BACKGROUND: Prostaglandin E2 (PGE2) can directly regulate toxic injury of hippocampal neurons through participation by its receptor. Increase of excitability of hippocampal membrane and long-term synaptic elasticity are closely related to PGE2, PGD2 and PGF2A. This suggests that PGE2 may be a key molecule of neuronal signal passage and regulate the existence of neurons through its receptor. However, which isoforms of PGE2 receptor expressing in hippocampal neurons is still unclear. OBJECTIVE: To research the subtype expression of PGE2 receptor in hippocampus of rats through mRNA transcription and protein interpretation. DESIGN: Animal studies with random, control and operator and designer double-blind methods. SETTING: University of South Carolina, Animal Center. MATERIALS: Sprague-Dawley rats, aged 12 weeks, weighing 200 g, females 48 and males 48, were selected from Animal Center in South Carolina University. Tri ReagentTM kit was provided by Molecular Research Center, USA. METHODS: The experiment was carried out in Animal Center in South Carolina University from January to December 2005. The expression of the PGE2 receptors was profiled and compared in rat hippocampus using real-time RT-PCR and Western-blot techniques. MAIN OUTCOME MEASURES: Expression of PGE2 receptors in various isoforms of hippocampal neurons of rats. RESULTS: mRNAs of all four EP1-4 subtypes were detected in the hippocampus. Western-blot data showed consistently detectable bands at approximately Mr 50 000 of EP1, Mr 40 000 and Mr 52 000 of EP2, Mr 45 000, Mr 57 000 and Mr 105 000 of EP3, and Mr 46 000 of EP4. CONCLUSION: Identifying four subtypes of EPs heterogeneously expresses in the hippocampus.

Combination of Paracetamol and the Glutathione Depleting Agent Buthionine Sulfoximine Show Differential Effect on Liver Cancer Cells and Normal Hepatocytes

Background: Paracetamol exerts toxic effects on liver cells through its metabolism into N-acetyl-p-benzoquinone imine (NAPQI), which is detoxified by conjugation with cellular glutathione (GSH). Once GSH is depleted, NAPQI stimulates a range of oxidative reactions that result in cell necrosis. The aim of the present investigation is to find a new strategy that would selectively protect normal hepatic tissues and sensitize liver cancer cells to the toxic effects of paracetamol or its metabolite. This may lead to the development of a targeted therapy for liver cancer. Methods: The anti-proliferative effects of paracetamol and buthionine sulfoximine BSO (a glutathione depleting agent) alone and in combination on the liver cancer cells HepG2 and normal rat hepatocytes were investigated by sulphorhodamine-B assay. Effects on cell cycle regulation and induction of apoptosis were tested by flow cytometry. The level of prostaglandin expression was measured by ELISA. Results: The present study showed that both agents alone or in combination have anti-proliferative effects on both cell types. Surprisingly, BSO showed a cytoprotective effects on normal hepatocytes treated with high concentrations (1.75 and 2 mM) of paracetamol. This was confirmed by cell cycle analysis that recorded decreased fraction of sub-G1 cells indicating reduction of apoptosis in normal hepatocytes. Analysis of prostaglandin E2 revealed differential effects of paracetamol on normal and liver cancer cells. A significant increase in PGE2 level over the control was observed in normal hepatocytes whereas a significant decrease was seen in HepG2 cells after treatment with paracetamol. Conclusion: These results indicate that combination of paracetamol/BSO has differential effects on liver cancer cells and normal hepatocytes, which opens the avenue for a new effective and selective combination for management of liver cancer.

Mating behaviors in ovoviviparous black rockfish(Sebastes schlegelii):molecular function of prostaglandin E2 as both a hormone and pheromone

Prostaglandins(PGs)are profound hormones in teleost sexual behavior,especially in mating.PGs act as pheromones that affect the olfactory sensory neurons of males,inducing the initiation of a series of mating behaviors.However,the molecular mechanism by which PGs trigger mating behavior in ovoviviparous teleosts is still unclear.In the present study,we employed the ovoviviparous black rockfish(Sebastes schlegelii),an economically important marine species whose reproductive production is limited by incomplete fertilization,as a model species.The results showed that when the dose of PGE2 was higher than 10 nmol/L,a significant(P<0.05)increase in mating behaviors was observed.Dual-fluorescence in situ hybridization indicated that PGE2 could fire specific neurons in different brain regions and receptor cells in the olfactory sac.After combining with specific neurons in the central nervous system(CNS),a series of genes related to reproduction are activated.The intracerebroventricular administration of PGE_(2) significantly increased lhb levels(P<0.05)in both sexes.Moreover,steroidogenesis in gonads was also affected,inducing an increase(P<0.05)in E_(2) levels in males and T levels in females.PGE_(2) levels were also increased significantly(P<0.05)in both sexes.The present study revealed that PGE2 can activate mating behavior in black rockfish in both hormone and pheromone pathways,leading to variations in sex steroid levels and activation of reproductive behaviors.Our results provide not only novel insight into the onset of mating behaviors in ovoviviparous teleosts but also solutions for the incomplete fertilization caused by natural mating in cage aquaculture.