Expression and significance of cyclooxygenase-2 mRNA in benign and malignant ascites

AIM:To investigate the mRNA expression of cyclooxygensae-2(COX-2)in benign and malignant ascites,and to explore the difference in COX-2 mRNA expression among different diseases.METHODS:A total of 36 samples were collected from the Fifth Affiliated Hospital of Sun Yat-Sen University and divided into two experimental groups:benign ascites(n=21)and malignant ascites(n=15).Benign ascites included cirrhotic ascites(n=10)and tuberculous ascites(n=5).Malignant ascites included oophoroma(n=7),cancer of colon(n=5),cancer of the liver(n=6),gastric cancer(n=2),and bladder carcinoma(n=1).The mRNA expression of COX-2 in ascites was examined with reverse transcriptase polymerase chain reaction(RT-PCR)technology,and the positive rate of COX-2 mRNA was compared between different diseases.RESULTS:The positive rate of COX-2 mRNA in malignant ascites was 42.9%(9/21),which was significantly higher than in benign ascites,6.7%(1/15),difference being significant between these two groups(χ2=4.051,P=0.044).The proportion of the positive rate in the malignant ascites was as follows:ovarian cancers57.1%(4/7),colon cancer 40.0%(2/5),liver cancer33.3%(2/6),gastric cancer 50.0%(1/2),and bladder cancer 0.00%(0/1).However,there was no significant difference in COX-2 mRNA expression among various tumors with malignant ascites(χ2=1.614,P=0.806).Among the benign ascites,COX-2 mRNA levels were different between the tuberculous ascites(0/5)and cirrhotic ascites(1/10),but there was no significant difference(P=1.000).CONCLUSION:COX-2 mRNA,detected by RT-PCR,is useful in the differential diagnosis of benign and malignant ascites,which also has potential value in the clinical diagnosis of tumors.

O-GlcNAcylation in Ventral Tegmental Area Dopaminergic Neurons Regulates Motor Learning and the Response to Natural Reward

Protein O-GlcNAcylation is a post-translational modification that links environmental stimuli with changes in intracellular signal pathways,and its disturbance has been found in neurodegenerative diseases and metabolic disorders.However,its role in the mesolimbic dopamine(DA)system,especially in the ventral tegmental area(VTA),needs to be elucidated.Here,we found that injection of Thiamet G,an O-GlcNAcase(OGA)inhibitor,in the VTA and nucleus accumbens(NAc)of mice,facilitated neuronal O-GlcNAcylation and decreased the operant response to sucrose as well as the latency to fall in rotarod test.Mice with DAergic neuron-specific knockout of O-GlcNAc transferase(OGT)displayed severe metabolic abnormalities and died within 4–8 weeks after birth.Furthermore,mice specifically overexpressing OGT in DAergic neurons in the VTA had learning defects in the operant response to sucrose,and impaired motor learning in the rotarod test.Instead,overexpression of OGT in GABAergic neurons in the VTA had no effect on these behaviors.These results suggest that protein O-GlcNAcylation of DAergic neurons in the VTA plays an important role in regulating the response to natural reward and motor learning in mice.