[Observation on experimental liver fibrosis and hepatic carcinogenesis of HBV gene knock-in transgenic mice induced by CCl4/ethanol].

OBJECTIVE: To study the effects of carbon tetrachloride (CCl4)/ethanol induction upon experimental liver fibrosis and hepatic carcinogenesis of HBV transgenic mice. METHODS: The wild-type mice, p21-HBx transgenic mice with integration of p21 locus by HBx gene and p21-HBsAg transgenic mice with integration of p21 locus by HBsAg gene were induced separately by CCl4/ethanol twice weekly for 20 weeks. The investigators observed the development of liver fibrosis and hepatic carcinogenesis in three groups and detected the gene expressions of HBx and HBsAg by RT-PCR. RESULTS: The expression of HBx or HBsAg mRNA existed in both control and induced transgenic mice, but in none of wild-type mice. Comparing with wild-type mice, p21 genes was not expressed in livers of transgenic mice. After induction by CCl4/ethanol, the fibrotic degrees of liver were not significantly different among wild-type mice, p21-HBx transgenic mice and p21-HBsAg transgenic mice, as well as between male and female mice. Reversely, the incidence rates of hepatic carcinogenesis of two HBV gene knock-in transgenic mouse lines (p21-HBx & p21-HBsAg) were higher than that of wild-type mice. And the incidence rate of hepatic carcinogenesis in males was also markedly higher than that in females. Induction by CCl4/ethanol markedly promoted and accelerated hepatic carcinogenesis in transgenic mice. CONCLUSIONS: Integration of HBsAg and HBx genes into the murine p21 locus can significantly promote the progression of hepatic carcinogenesis, but failed to promote the progression of liver fibrosis. The male mouse is more likely to develop experimental hepatocellular carcinoma than the female mouse. Experimental hepatocellular carcinoma induced by CCl4/ethanol in p21-HBx and p21-HBsAg transgenic mice is a feasible animal model.

[Effects of Smad4 on liver fibrosis and hepatocarcinogenesis in mice treated with CCl4/ethanol].

To study the effects of Smad4 on liver fibrosis and hepatocarcinogenesis in mice treated with CCl(4)/ethanol. The wild-type mice (Smad4 +/+) and the Smad4 knockout mice (Smad4 +/-) were injected subcutaneously with carbon tetrachloride(CCl(4))/ethanol twice a week for twenty weeks. The expression of Smad4, TGFbeta1, Smad2, Smad3, Smad6, TIMP1, MMP2 and MMP9 was detected by RT-PCR. In the cirrhotic liver, the expression of Smad4 mRNA was significantly higher than that in the normal liver. Comparing with wild-type mice (Smad4 +/+), the TGFbeta1-Smad4 signaling was markedly attenuated in the Smad4 knockout mice (Smad4 +/-). After induction by CCl(4)/ethanol, the hepatic fibrosis in the Smad4 knockout mice (Smad4 +/-) was obviously alleviated compared with the wild-type mice (Smad4 +/+), and the incidence rate of hepatocarcinogenesis of the former was also lower than that of the latter(32.0% vs 41.9%). These results indicate that knocking out Smad4 can delay the progression of liver fibrosis and liver cancer.

[Surgical treatment for hilar cholangiocarcinoma of Bismuth-Corlette type IV].

OBJECTIVE: To investigate the surgical treatment for hilar cholangiocarcinoma(HCCA) of Bismuth-Corlette type IV. METHODS: The clinical data of 73 HCCA patients admitted in Southwest Hospital, the Third Military Medical University from January 2002 to December 2008 were analyzed retrospectively. There were 41 males and 32 females, aged from 30 to 84 years old (averaged, 56.8 years old). All patients were diagnosed as hilar mass with hilar biliary obstruction by B-ultrasound, CT, magnetic resonance imaging, endoscopic retrograde cholangiopancreatography, magnetic resonance cholangiopancreatography or percutaneous transhepatic cholangiography, and confirmed by pathological examination in intra-operation and post-operation. Diagnosis of all patients were according to Bismuth-Corlette type IV. RESULTS: Fifteen cases underwent percutaneous transhepatic cholangial drainage, stents were implanted in 8 patients. Simple internal drainage was performed on 25 of the 73 patients and 4 with palliative resection. Radical resection was performed on 19 patients. The radical resection rate of HCCA were 26.0%. The 1, 3 years of survival rates were 36.8%, 10.5% respectively. The 1 year survival rate was 6.3% in drainage group. CONCLUSION: Radical resection is the potentially curative treatment for HCCA, a sufficient, reasonable use of internal and external drainage would improve the patient's quality of life.

[Experimental study on tolerance time limits from warm ischemia to cold preservation of liver grafts].

OBJECTIVE: To investigate the tolerance time limits from warm ischemia to cold preservation of liver grafts. METHODS: Orthotopic liver transplantations (OLTs) were performed on Bama miniature swine. Morphological and functional changes of the liver grafts and biliary tracts after 10 minutes of warm ischemia followed by different durations of cold preservation and its reversibility were investigated. RESULTS: When the grafts were subjected to 10 minutes of warm ischemia followed by less than 16 hours of cold preservation, all animals could survive 1 week and there was no animal death from biliary necrosis. However, when the cold preservation time exceeded 16 hours, the incidence of biliary necrosis was significantly increased (P<0.05), and recipient death from bile leaks occurred. With further prolongation of the cold preservation time, primary graft nonfunction and intraoperative or early postoperative deaths occurred and the living animals all developed biliary necrosis. When compared with the less than 16 hours cold preservation group, the morphological scores and apoptosis index of the epithelial cells of bile ducts in grafts after reperfusion were significantly elevated in the more than 16 hours cold preservation group (P<0.05) and the activity of Na+-K+-ATPase and Ca2+-ATPase of bile ducts in grafts were also significantly reduced (P<0.05). Liver function tests showed that the recoveries of AST, AST, GGT and ALP were quicker in the 16 hours cold preservation group then those over 16 hour preservation ones. Correlation analysis revealed that the incidence of biliary necrosis was significantly correlated with the morphological score (r = 0.972) and with the apoptosis index of the epithelial cells of bile ducts in grafts after reperfusion (r = 0.931) and also correlated negatively (P<0.01) with the activity of Na+-K+-ATPase (r = -0.973) and Ca2+-ATPase (r = -0.973). CONCLUSIONS: It is concluded that with 10 minutes of warm ischemia, cold preservation of the grafts should not be longer than 16 hours in order to avoid early biliary necrosis, and the corresponding tolerance time limit of the livers to the cold preservation was less than 20 hours.

[Effect of proto-oncogene protein c-met ribozyme transfection on biological behavior of gastric carcinoma cells].

OBJECTIVE: To explore the effect of c-met ribozyme transfection on biological behavior of gastric carcinoma cells. METHODS: U1/met292 plasmid containing c-met ribozyme gene was transfected into L2 subline of SGC-7901 gastric cell line, and the proliferative ability, distribution of cell cycle, protein expression of VEGF and c-met, as well as the potential of liver metastasis of the transfected subline were determined. RESULTS: There were no significant difference in proliferative ability, distribution of cell cycle between the transfected cells and the control cells. The protein expression of VEGF and c-met, as well as the liver metastatic potential significantly decreased in the transfected cells than those in the control cells (P< 0.05). CONCLUSION: The liver metastatic potential of c-met positive gastric cancer cells may be prevented by inhibiting c-met expression.

Clinical analysis of surgical treatment of portal hypertension.

AIM: To review the experience in surgery for 508 patients with portal hypertension and to explore the selection of reasonable operation under different conditions. METHODS: The data of 508 patients with portal hypertension treated surgically in 1991-2001 in our centers were analyzed. Of the 508 patients, 256 were treated with portaazygous devascularization (PAD), 167 with portasystemic shunt (PSS), 62 with selective shunt (SS), 11 with combined portasystemic shunt and portaazygous devascularization (PSS+PAD), 9 with liver transplantation (LT), 3 with union operation for hepatic carcinoma and portal hypertension (HCC+PH). RESULTS: In the 167 patients treated with PSS, free portal pressure (FPP) was significantly higher in the patients with a longer diameter of the anastomotic stoma than in those with a shorter diameter before the operation (P < 0.01). After the operation, FPP in the former patients markedly decreased compared to the latter ones (P < 0.01). The incidence rate of hemorrhage in patients treated with PAD, PSS, SS, PSS+PAD, and HCC+PH was 21.09% (54/256), 13.77 (23/167), 11.29 (7/62), 36.36% (4/11), and 100% (3/3), respectively. The incidence rate of hepatic encephalopathy was 3.91% (10/256), 9.58% (16/167), 4.84% (3/62), 9.09% (1/11), and 100% (3/3), respectively while the operative mortality was 5.49% (15/256), 4.22% (7/167), 4.84% (3/62), 9.09% (1/11), and 66.67% (2/3) respectively. The operative mortality of liver transplantation was 22.22% (2/9). CONCLUSION: Five kinds of operation in surgical treatment of portal hypertension have their advantages and disadvantages. Therefore, the selection of operation should be based on the actual needs of the patients.

[Radiofrequency ablation for hypersplenism due to portal hypertension: clinical study].

OBJECTIVE: To investigate the feasibility, efficacy and clinical prospects of radiofrequency ablation (RFA) for hypersplenism in patients with liver cirrhosis and portal hypertension. METHODS: The laboratory and radiologic data over one-year period of patients undergone splenic RFA were analyzed. RESULTS: Nine patients undergone splenic RFA has closely followed-up over 1 year. During hospitalization, no procedure-related complications occurred, only minor complications including hydrothorax (3/9 patients) and mild abdominal pain (4/9 patients) were observed. After treatment, average 30.7% (20%-43%) of spleen volume was ablated, and the platelet count reached peak on 14th post-procedure day. White blood cell and platelet counts, liver function, and hepatic artery blood flow had gained significant improvements comparing with those before RFA procedures. Hyperplasia/regeneration was also occurred in cirrhotic liver after splenic RFA. CONCLUSION: Radiofrequency ablation is a safe, effective and minimally invasive approach for the management of hypersplenism in patients with liver cirrhosis and portal hypertension. Increased hepatic artery blood flow can contribute to significant improvement of liver function, and maybe potentially stimulate liver regeneration in cirrhotic liver.

[Effects of portaazygous disconnection, portocaval shunt and selective shunts on experimental rat liver cirrhosis].

OBJECTIVE: To evaluate the effects of portaazygous disconnection (PAD), portacaval shunt (PCS) and distal splenocaval shunt (DSCS) on the portosytemic shunting (PSS), hepatic function (HF), hepatic mitochondrial respiratory function (HMRF), oral glucose tolerance test (OGTT) and arterial ketone body ratio (KBR) in order to provide a sound basis for selecting suitable operations for patients. METHODS: Using a cirrhotic portal hypertensive model induced by CCl4/ethanol in Wistar rats, the PSS, HF, HMRF, OGTT and KBR were determined three weeks after PCS, DSCS and PAD. RESULTS: It was revealed that: (1) In the cirrhotic portal hypertension rats, the PSS increased significantly, HMRF and hepatic reserve function (HRF) decreased significantly when compared with the control rats. (2) At the time of first postoperative week, the mean blood glucose value in the 120-minute OGTT in each PAD, PCS and DSCS groups had significant differences compared with the cirrhotic control group. But during the second and third postoperative weeks, the mean blood glucose values in the 120-minute OGTT in both PAD and DSCS groups had no significant differences compared with the cirrhotic control group except for the PCS group. The values of KBR in the three operative groups decreased significantly compared with the cirrhotic control group during the two postoperative weeks. In the third postoperative week, only the values of KBR in the PCS group had a significant difference compared with the cirrhotic control group. (3) After PCS, the PSS was further increased; HF and HMRF were significantly decreased. Little improvement was found in the third postoperative week. (4) After DSCS and PAD, the above mentioned indices were less influenced, and they were restored more quickly than those in the PCS group. CONCLUSION: We found that PAD and DSCS are more desirable than PCS.

Inhibitory effect of retroviral vector containing anti-sense Smad4 gene on Ito cell line, LI90.

BACKGROUND: Transforming growth factor-beta1 (TGF-beta1) exerts strong fibrogenic potential in culture-activated HSCs. Smad4 is a key intracellular mediator for the transforming growth factor-beta (TGF-beta) superfamily of growth factors. The aim of this study was to assess the effects of the antisense Smad4 gene on Ito cell line, LI90. METHODS: The recombinant retroviral vector pLXSN-Smad4 was constructed by cloning the rat antisense Smad4 cDNA into the retroviral vector pLXSN. Retroviruses with or without the antisense gene were obtained by transfecting pLXSN-Smad4 and pLXSN vectors into PA317 cells. Human hepatic stellate cells (HSCs) LI90 were infected with these retroviruses followed by selection with G418. The expression of Smad4 was detected by Northern and Western blots. Cell biological characteristics, including cell growth curve, 3H-TdR and 3H-proline uptake by HSCs and the production of extracellular matrix were assessed. RESULTS: mRNA and protein expressions of Smad4 in LI90 cells transfected with retrovirus containing the antisense Smad4 gene were much lower than those in LI90 cells transfected with empty vector or parental LI90 cells. Cells hypoexpressing the Smad4 gene exhibited a slower rate of growth, a lower uptake of 3H-TdR and 3H-proline (P < 0.01), and smaller production of th extracellular matrix, compared with parental LI90 cells and cells transfected with empty retrovirus. CONCLUSIONS: The antisense Smad4 gene can suppress the expression of the Smad4 gene, reduce endogenous production of Smad4 mRNA and protein, block TGF-beta1 signaling pathway, inhibit activation of Ito cells, obstruct the growth of Ito cells, decrease the production of the extracellular matrix (ECM). Our results may provide a basis for the development of antifibrotic gene therapy.

[Obstruction of TGF-beta1 signal transduction can decrease the process of hepatocellular carcinoma in mice induced by CCl4/ethanol].

OBJECTIVE: To study obstruction of the TGF-beta(1) signal transduction by antisense RNA of Smad(4) and its effects on experimental hepatic carcinoma of mice. METHODS: We used the mouse model of primary hepatic carcinoma induced by CCl(4)/ethanol, and transferred antisense Smad(4)cDNA with retrovirus-mediated via portal vein infusion into liver. Southern Blot confirmed that the antisense Smad(4)cDNA had been integrated into the liver. The antisense Smad(4) gene could down-regulate the expression of Smad(4) in fibrotic liver observed by Northern and Western Blot. RESULTS: In the non-therapeutic cirrhotic liver, the expression of Smad(4) mRNA was significantly increased than normal liver. After antisense Smad(4) gene was transferred, the expression of Smad(4) mRNA in the therapeutic liver was significantly decreased compared with non-therapeutic cirrhotic liver. The fibrotic degree of therapeutic liver was alleviated compared with the non-therapeutic fibrotic liver. No significant difference was found between the rates of carcinogenesis of non-therapeutic cirrhotic liver and that of therapeutic cirrhotic liver. But the diameters and numbers of the liver cancers in the therapeutic cirrhotic group were less than that in the non-therapeutic cirrhotic group. CONCLUSION: These results indicate that the antisense Smad(4) gene not only can obstruct the progression of liver fibrosis, but also can inhibit the progression of liver cancer, by obstructing the signal transduction of TGF-beta1.

[Effects of anti-sense Smad4 gene on the biological characteristics of the fat-storing cell line CFSC].

OBJECTIVE: To investigate the effects of antisense Smad(4) on the biological characteristics of the fat-storing cell line CFSC. METHODS: Fat-storing cells of line CFSC from rat with liver fibrosis were cultured and transfected with 50 MOI of recombinant adenoviral vector carrying antisense Smad(4) (AdvATSmad(4)) or the control empty adenovirus (Adv0), both produced by 293 packaging cells, respectively. Two, four, and six days after the transfection the cultured cells were collected to undergo trypan blue staining and cell counting. The growth curves were drawn. The presence of antisense Smad(4) was detected by RT-PCR and Western blotting. (3)H-TdR was added into the culture media to be co-cultured for 6 hours. Then the cells were collected to examine the (3)H-TdR incorporation rate. RT-PCR and immunohistochemistry were used to examine the expression of COL1A1 and type I collagen, kinds of extracellular matrix (ECM). RESULTS: Compared with the control CFSC and the Adv0-transfected CFSC cells, the cell growth curve, (3)H-TdR incorporation rate, proline incorporation rate, expression of Smad(4), and expression of extracellular matrix were markedly decreased in the AdvATSmad(4)-transfected CFSCs. CONCLUSION: The antisense Smad(4) gene inhibits the expression of Smad(4) mRNA and protein, proline incorporation and cell growth, thus down-regulating the production of ECM. Antisense Smad(4) gene may be used as a choice of gene therapy for liver fibrosis.

[Obstruction of TGF-beta1 signal transduction by anti-Smad4 gene can therapy experimental liver fibrosis in the rat].

OBJECTIVE: To study the therapeutic effects to block the TGF-beta1 (transforming growth factor beta1) signal transduction by antisense Smad4 gene on experimental fibrotic liver. METHODS: Using the rat model of liver fibrosis induced by Carbon Tetrachloride (CCl4)/ethanol, we transfected antisense Smad4 gene mediated by adenovirus via portal vein infusion into the liver, and observed the expression of Smad4 by Retro-Polymerase Chain Reaction (RT-PCR) and Western Blot. We also investigated the pathologic features and collagen expression. RESULTS: In the non-therapeutic cirrhotic liver, the expression of Smad4 mRNA was significantly increased than normal liver, and so was the collagen I. After antisense Smad4 gene being transfected, the expression of Smad4 mRNA and that of collagen I in the therapeutic liver was significantly decreased, compared with the non-therapeutic cirrhotic liver. The fibrous degree of therapeutic liver was also reduced compared with the non-therapeutic fibrous liver. CONCLUSION: These results indicate that because antisense Smad4 gene could block TGF-beta1 signal transduction by reducing the expression of Smad4, so it could inhibit the production of extracellular matrix (ECM) and improve hepatic fibrosis.

Etiology and surgical treatment of hilar bile duct stricture.

OBJECTIVE: To improve the surgical effects of hilar duct stricture. METHODS: The clinical data of 76 patients with hilar bile duct stricture treated at our hospital from 1990 to 2000 were analyzed. The diagnosis was determined by triad signs of cholangitis, increase of ALP and gamma-GGT levels, dilation of intrahepatic and extrahepatic bile ducts confirmed by ultrasonography (US), computed tomography (CT), percutaneous transhepatic cholangiography (PTC) or endoscopic retrograde cholangiopancreatography (ERCP). The location of stricture was divided according to the Bismuth classification standard. RESULTS: Among the 76 patients, 46 (60.5%) suffered from injurious stricture, including 13% of Bismuth type I, 39% of type II, 19.4% of type III, and 28.2% of type IV. Inflammatory stricture was found in 28 patients, locating in the left hepatic duct (LHD) 46.4% (13/28), the right hepatic duct (RHD) 35.7% (10/28), and the common hepatic duct (CHD) 17.9% (5/28), respectively. The percentages of patients with stricture due to Mirizzi's syndrome, bile duct cyst, and sclerosing cholangitis were 9.2%, 3.9% and 2.6%, respectively. Bile duct repair procedures included biliary reconstruction with pedicled umbilical vein graft for 9.2% of the patients, and proximal cholangiojejunostomy combined with LHD and RHD plasticity for 92.2%. Seventy of the 76 patients were followed up for 2-10 years, and the excellent outcome rate was 94.7%. CONCLUSIONS: Injurious stricture is the major type of hilar bile duct stricture. Inflammatory stricture is mainly composed of RHD. Hilar bile duct stricture should be treated surgically according to various etiological features and technical principles of biliary repair.

Preoperative selective portal vein embolization in two-step hepatectomy for hepatocellular carcinoma in injured livers: a preliminary report.

OBJECTIVE: To study the effect of preoperative selective portal vein embolization (SPVE) in the two-step hepatectomy for patients with primary hepatocellular carcinoma (HCC) in injured livers. METHODS: Twenty-six patients with HCC and cirrhosis who were not suitable for curative hepatectomy were treated by ultrasound-guided percutaneous transhepatic SPVE with a fine needle. The success rate, side-effects and complications of SPVE, serial changes of hepatic lobe volume and rate of two-step curative hepatectomy after SPVE were observed. RESULTS: SPVE was performed in 24 patients (92.3%). In patients whose right portal vein branches were embolized, the right hepatic volume decreased but the left hepatic volume increased gradually. The ratio of the right hepatic volume to the total hepatic volume decreased from 64.0% before SPVE to 60.8% after l week, 55.1% after 2 weeks and 52.7% after 3 weeks, respectively. The side-effects included different degree of pain in the liver quandrant (17 patients), lower fever (9), and nausea and vomiting (7). The levels of aspartate alanine transaminase (AST), alanine transaminase (ALT) and total bilirubin (TBIL) increased after SPVE, but returned to the preoperative levels in 1 week. After 2-4 weeks, two-step curative hepatectomy for HCC was performed in 13 patients (54.2%). CONCLUSIONS: Ultrasound-guided percutaneous transhepatic SPVE with a fine needle is feasible and safe. It can extend the indications of curative hepatectomy for HCC in injured livers, and increase the safety of two-step hepatectomy.

Role of preoperative selective portal vein embolization in two-step curative hepatectomy for hepatocellular carcinoma.

AIM: To determine the feasibility and role of ultrasound-guided preoperative selective portal vein embolization (POSPVE) in the two-step hepatectomy of patients with advanced primary hepatocellular carcinoma (HCC). METHODS: Fifty patients with advanced HCC who were not suitable for curative hepatectomy were treated by ultrasound-guided percutaneous transhepatic POSPVE with fine needles. The successful rate, side effects and complications of POSPVE, changes of hepatic lobe volume and two-step curative hepatectomy rate after POSPVE were observed. RESULTS: POSPVE was successfully performed in 47 (94.0 %) patients. In patients whose right portal vein branches were embolized, their right hepatic volume decreased and left hepatic volume increased gradually. The ratio of right hepatic volume to total hepatic volume decreased from 62.4 % before POSPVE to 60.5 %, 57.2 % and 52.8 % after 1, 2 and 3 weeks respectively. The side effects included different degree of pain in liver area (38 cases), slight fever (27 cases), nausea and vomiting (9 cases). The level of aspartate alanine transaminase (AST), alanine transaminase (ALT) and total bilirubin (TBIL) increased after POSPVE, but returned to preoperative level in 1 week. After 2-4 weeks, two-step curative hepatectomy for HCC was successfully performed on 23 (52.3 %) patients. There were no such severe complications as ectopic embolization, local hemorrhage and bile leakage. CONCLUSION: Ultrasound-guided percutaneous transhepatic POSPVE with fine needles is feasible and safe. It can extend the indications of curative hepatectomy of HCC, and increase the safety of hepatectomy.

[The feasibility and safety of radiofrequency ablation for secondary splenomegaly and hypersplenism in dogs].

OBJECTIVE: To assess the feasibility and safety of radiofrequency ablation (RFA) in spleen to treat secondary splenomegaly and hypersplenism in dogs. METHODS: Fourteen healthy mongrel dogs were randomly divided into two groups: group A (n = 4) and group B (n = 10) Both groups underwent ligation of the splenic vein and its collateral branches to induce congestive splenomegaly. At the end of the 3rd week, radiofrequency thermal ablation of the spleen was performed in the group B via laparotomy. After splenic RFA, the procedure-related complications were observed, CT scan was performed and the spleens were obtained according to schedule. The radiofrequency (RF) thermal lesions and its histo- pathological changes of the spleen were examined regularly. RESULTS: There were no morbidity and mortality in the experimental dogs. CT findings revealed that splenomegaly could sustained over 2 months after ligation of the splenic vein. The segmental RF lesions included hyperintense zone of coagulative necrosis and more extensively peripheral hypo-intense infarcted zone. The latter was called as "bystander effect". The infarcted zone would be absorbed and subsequently disappeared between 4 and 6 weeks after RFA, and the size of the remnant spleen shrunk, but the lesion of coagulative necrosis hardly altered. The fundamental histopathological changes of splenic lesions caused by RF thermal energy included local coagulative necrosis and the peripheral thrombotic infarction zone. Subsequently, tissue absorption and fibrosis occurred in the zone of thrombotic infarction. Simultaneously occluded vessels, fibrin deposition, and disappearance of normal splenic sinuses resulted in the condensed structure of the viable remnant spleen, which were the pathological basis responsible for the shrunk spleen. CONCLUSIONS: It is feasible and safe to perform RFA in the spleen to treat experimental splenomegaly and hypersplenism. The RFA technique could be safely performed clinically via laparotomy or laparoscopic procedure to strictly isolate the spleen from the surrounding organs.

Experimental study on the feasibility and safety of radiofrequency ablation for secondary splenomagely and hypersplenism.

AIM: To assess the feasibility and safety of radiofrequency ablation (RFA) in treatment of secondary splenomagely and hypersplenism. METHODS: Sixteen healthy mongrel dogs were randomly divided into two groups, group I (n=4) and group II (n=12). Congestive splenomegaly was induced by ligation of splenic vein and its collateral branches in both groups. At the end of 3rd week postoperation, RFA in spleen was performed in group II via laparotomy, complications of RFA were observed, CT scan was performed and the spleens were obtained. The radiofrequency (RF) thermal lesions and histopathology of spleen were examined regularly. RESULTS: No complication or death was observed in both groups; CT revealed that the splenomegaly lasted over 2 months after ligation of splenic vein; the segmental RF lesions included hyperintense zone of coagulative necrosis and more extensive peripheral hypointense infarcted zone, the latter was called "bystander effect". The infarcted zone would be absorbed and subsequently disappeared in 4-6 weeks after RFA accompanied with shrinkage of the remnant spleen. The fundamental histopathological changes of splenic lesions caused by RF thermal energy included local coagulative necrosis, peripheral thrombotic infarction zone, subsequent tissue absorption and fibrosis in the zone of thrombotic infarction, the occlusion of vessels in remnant viable spleen, deposition of extensive fibrous protein, and disappearance of congestive splenic sinusoid - "splenic carnification". Those pathologic changes were underline of shrinkage of spleen. CONCLUSION: It is feasible and safe to perform RFA in spleen to treat experimental splenomegaly and hypersplenism. The RFA could be safely performed clinically via laparotomy or laparoscopic procedure while spleen was strictly separated from surrounding organs.