[Protection of oxymatrine against ischemia-reperfusion injury of liver and mechanism thereof: experiment with rats].

OBJECTIVE: To investigate the effects of oxymatrine on protecting the liver against ischemia-reperfusion injury (IRI) and explore the mechanism thereof. METHODS: Thirty male Wistar rats were randomly divided into 3 equal groups: IRI group (2 ml normal saline was injected into the dorsal vein of penis, 30 min later laparotomy was performed, arterial clamp was used to grip the hepatic artery and portal vein for 30 minutes and then removed, the vessels were reperfused for 90 min, and 4 ml blood was collected from the aorta; parts of the liver were resected); oxymatrine group (oxymatrine 40 mg/kg was injected into the dorsal vein of penis, and the other procedures were the same as in the IRI group); and sham operation group (2 ml normal saline was injected into the dorsal vein of penis, laparotomy was performed, 150 min after the injection 4 ml blood was collected from the aorta and parts of the liver were resected). The levels of alanine transaminase (ALT) and aspartate transaminase (AST) were detected. The liver tissues underwent HE staining and TUNEL staining for pathological examination. Suspension of single hepatocytes was prepared to observe the ratio of apoptotic cells and cell cycles by flow cytometry (FCM). Western blotting was used to examine the Fas protein expression. RESULTS: The AST and ALT levels of the IRI group were 1326 U/L +/- 211 U/L and 768 U/L +/- 175 U/L respectively, significantly higher than those of the sham operation group (112 U/L +/- 53 U/L and 55 U/L +/- 17 U/L, both P < 0.05) and those of the oxymatrine group (513 U/L +/- 96 U/L and 352 U/L +/- 72 U/L respectively, both P < 0.01). The liver cells of the sham operation group were normal, those of the IRI group showed remarkable edema and cytoplasm degeneration. TUNEL staining showed remarkably more apoptotic cells in the IRI group. FCM showed that the apoptotic rate of hepatocytes was 42.8% +/- 5.2% in the IRI group, significantly higher than in the oxymatrine group (8.8% +/- 1.8%, P < 0.01), and that the ratio of hepatocytes in G(0)/G(1) stage of the IRI group was 99.2% +/- 1.8%, significantly higher than that of the sham operation group (77.0% +/- 2.1%), and that of the oxymatrine group (87.6% +/- 2.8%) (both P < 0.05); the ratio of hepatocytes in the S stage of the IRI group was 0.52% +/- 0.25%, significantly lower than those of the sham operation group (23.94% +/- 1.84%) and oxymatrine group (12.42% +/- 0.46%) (both P < 0.01). The Fas protein expression was significantly highly in the IRI group than in the oxymatrine group. CONCLUSION: Remarkably reducing the IRI of hepatocytes, oxymatrine has potential to protect the liver against IRI during surgical intervention.

[Expression of the cyclooxygenase-2 gene in human breast carcinoma].

OBJECTIVE: To study the expression of the cyclooxygenase-2 (COX-2) gene in breast cancer in contrast to that of normal breast tissues or benign breast tumors and its significance in the carcinogenesis and development of breast cancer. METHODS: With reference to the expression of the beta-actin gene, the expression of COX-2 mRNA was examined in cancerous tissues and adjacent normal breast tissue from 30 patients and benign breast tumors from 15 patients by reverse transcription-polymerase chain reaction (RT-PCR). Quantitation of relative band densities was performed using densitometry-scanning software. Estrogen receptors of 30 breast cancers were investigated by immunohistochemistry. RESULTS: Enhanced expression of COX-2 was observed in ninety percent of cancers tissue with a range of 0.05 - 0.91 (median 0.53). Rare cases showed significant COX-2 expression in normal breast tissues with a range of 0 - 0.09 (median 0). In part of benign breast tumors, COX-2 expressions were obviously elevated with a range of 0 - 0.68 (median 0.07). The difference of expression of COX-2 mRNA among breast cancers, normal breast tissues, mastopathy or fibroadenomas was significant (rank-sum test, P < 0.05) and the difference of that between estrogen receptor negative and positive was also observed (rank-sum test, P < 0.01). CONCLUSION: The level of expression of COX-2 mRNA is obviously higher in breast cancer tissue than in normal breast tissue, mastopathy or fibroadenomas. The expression of COX-2 in hormone-dependent breast cancer is higher than that in hormone-independent breast cancer. The overexpression of COX-2 may play a crucial role in the carcinogenesis and development of cancer in patients with breast carcinoma.