Modifi cation of sleep architecture in an animal model of experimental cirrhosis

AIM： To analyze the polygraphic sleep patterns during cirrhosis progression in a rat model by repeated CCh administration. METHODS： Male Wistar rats received three weekly injections of CCl4 for 11 wk, and were analyzed before and during the induction of cirrhosis. Rats were im- planted with electrodes to record their sleep patterns. Polygraph recordings were made weekly over 11 wk for 8 h, during the light period. After a basal recording, rats received three weekly injections of CCl4. Histological confirmation of cirrhosis was performed after 11 wk. RESULTS： The results showed a progressive decrease in total wake time that reached statistical significance from the second week of treatment. In addition, there was an increase in total time of slow wave sleep （SWS）Ⅱ and rapid eye movement sleep （REM sleep） in most of the 11 wk. SWS I showed no significant variations. During the final weeks, a significant increase in REM sleep frequency was also observed. Histological analyses of the livers showed unequivocal signs of cirrhosis. CONCLUSION： These data suggest that hepatic failure produced by CCh administration is capable of modifying the sleep pattern even after only a few doses.

Thrombospondin-1 expression correlates with angiogenesis in experimental cirrhosis

AIM:To investigate the significance of Thrombospondin-1 (TSP-1) expression and its relationship with angiogenesis during experimental fibrosis. METHODS:Cirrhosis was induced in male Wistar rats by intraperitoneal administration of diethyl nitrosamine (DEN). The serial sections from liver tissues were stained with anti-CD34 and anti-TSP-1 antibodies before being quantitated by light microscopy. RESULTS:Our results showed that of TSP-1 expression gradually increases according to the severity of fibrosis (GroupⅠvs group Ⅱ, Group Ⅲ and Group Ⅳ;Group Ⅱ vs group Ⅲ and group Ⅳ;group Ⅲ vs group Ⅳ, P < 0.05). Moreover, TSP-1 expression was found to be correlated with angiogenesis (P < 0.05). CONCLUSION:The correlative evidence of the link between TSP-1 and fibrosis or angiogenesis provided by this study suggests that besides its role as a strong promoter of transforming growth factor-β1 (TGF-β1), TSP-1 might have an additional role in liver fibrogenesis by stimulating angiogenesis and this protein could be a potential target to prevent fibrogenesis in chronic inflammatory diseases of the liver.

Regulating effect of Chinese herbal medicine on the peritoneal lymphatic stomata in enhancing ascites absorption of experimental hepatofibrotic mice

AIM: To observe the regulatory effect of Chinese herbal medicine on peritoneal lymphatic stomata and its significance in treating ascites in liver fibrosis model mice. METHODS: Two Chinese herbal composite prescriptions were used separately to treat the carbon tetrachloride-induced mouse model of liver fibrosis. The histo-pathologic changes of the liver sections (HE and VG stainings) were observed. The peritoneal lymphatic stomata was detected by scanning electron microscopy and computer image processing. The changes of urinary volume and sodium ion concentration were measured. RESULTS: In the model group, lots of fibrous tissue formed in liver and extended into the hepatic lobules to separate them incompletely. In the treated and prevention groups, the histo-pathologic changes of liver was rather milder, only showed much less fibrous tissue proliferation in the hepatic lobules. The peritoneal lymphatic stomata enlarged with increased density in the experimental groups (diameter: PA, 3.07 +/- 0.69 microm; PB, 2.82 +/- 0.37 microm; TA, 3.25 +/- 0.82 microm and TB, 2.82 +/- 0.56 microm; density: PA, 7.11 +/- 1.90 stomata.1000 microm(-2); PB, 8.76 +/- 1.45 stomata.1000 microm(-2); TA, 6.55 +/- 1.44 stomata.1000 microm(-2)and TB, 8.76+/-1.79 stomata.1000 microm(-2)), as compared with the model group (diameter: 2.00+/-0.52 microm density: 4.45+/-1.05 stomata.1000 microm(-2)). After treatment, the urinary volume and sodium ion excretion increased in the experimental groups (PA, 231.28+/-41.09 mmol.L(-1); PB, 171.69 +/- 27.48 mmol.L(-1) and TA, 231.44 +/- 34.12 mmol.L(-1)), which were significantly different with those in the model group (129.33 +/- 36.75 mmol.L(-1)). CONCLUSION: Chinese herbal medicine has marked effects in alleviating liver fibrosis, regulating peritoneal lymphatic stomata, improving the drainage of ascites from peritoneal cavity and causing increase of urinary volume and sodium ion excretion to reduce the water and sodium retention, and thus have favorable therapeutic effect in treating ascites.

Bone disorders in experimentally induced liver disease in growing rats

AIM： To investigate the change of bone parameters in a new model of experimentally induced liver cirrhosis and hepatocellular carcinoma （HCC） in growing rats. METHODS： Fischer-344 rats （n = 55） were used. Carbon tetrachloride （CCh）, phenobarbital （PB）, and a single diethylnitrosamine （DEN） injection were used. Animals were killed at wk 8 and 16. Bone mineral content, femoral length, cortical index （quotient of cortical thickness and whole diameter） and ultimate bending load （Fmax） of the femora were determined. The results in animals treated with DEN＋PB＋CCh （DPC, n = 21） were com- pared to those in untreated animals （UNT, n = 14） and in control group treated only with DEN＋PB （DP, n = 20）. RESULTS： Fatty liver and cirrhosis developed in each DPC-treated rat at wk 8 and HCC was presented at wk 16. No skeletal changes were found in this group at wk 8, but each parameter was lower （P〈0.05 for each） at wk 16 in comparison to the control group. Neither fatty liver nor cirrhosis was observed in DP-treated animals at any time point. Femoral length and Fmax values were higher （P〈0.05 for both） in DP-treated animals at wk 8 compared to the UNT controls. However, no difference was found at wk 16. CONCLUSION： Experimental liver cirrhosis and HCC are accompanied with inhibited skeletal growth, reduced bone mass, and decreased mechanical resistance in growing rats. Our results are in concordance withthe data of other studies using different animal models. A novel finding is the transiently accelerated skeletal growth and bone strength after a 8-wk long phenobarbital treatment following diethylnitrosamine injection.

Effect of L-NAME on nitric oxide and gastrointestinal motility alterations in cirrhotic rats

AIM: To investigate the effect of L-NAME on nitric oxide and gastrointestinal motility alterations in cirrhotic rats. METHODS: Rats with cirrhosis induced by carbon tetrachloride were randomly divided into two groups, one n =13 receiving 0.5mg.kg(-1) per day of N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, for 10 days, whereas the other group (n =13) and control (n =10) rats were administrated the same volume of 9g.L(-1) saline. Half gastric emptying time and 2h residual rate were measured by SPECT, using (99m)Tc-DTPA-labeled barium sulfate as test meal. Gastrointestinal transition time was recorded simultaneously. Serum concentration of nitric oxide (NO) was determined by the kinetic cadmium reduction and colorimetric methods. Immunohistochemical SABC method was used to observe the expression and distribution of three types of nitric oxide synthase (NOS) isoforms in the rat gastrointestinal tract. Western blot was used to detect expression of gastrointestinal NOS isoforms. RESULTS: Half gastric emptying time and trans-gastrointestinal time were significantly prolonged(124.0 +/- 26.4 min; 33.7 +/- 8.9 min; 72.1 +/- 15.3 min; P【0.01), (12.4 +/- 0.5h; 9.5 +/- 0.3h; 8.2 +/- 0.8h; P【0.01), 2h residual rate was raised in cirrhotic rats than in controls and cirrhotic rats treated with L-NAME (54.9 +/- 7.6%,13.7 +/- 3.2%, 34.9 +/- 10.3%, P【0.01). Serum concentration of NO was significantly increased in cirrhotic rats than in the other groups (8.20 +/- 2.48) micromol.L(-1), (5.94 +/-1.07) micromol.L(-1) and control (5.66 +/- 1.60 micromol.L(-1), P【0.01. NOS staining intensities which were mainly located in the gastrointestinal tissues were markedly lower in cirrhotic rats than in the controls and cirrhotic rats after treated with L-NAME. CONCLUSION: Gastrointestinal motility was remarkably inhibited in cirrhotic rats, which could be alleviated by L-NAME. Nitric oxide may play an important role in the inhibition of gastrointestinal motility in cirrhotic rats.

Safe upper limit of intermittent hepatic inflow occlusion for liver resection in cirrhotic rats

AIM: To evaluate the effects of varying ischemic durations on cirrhotic liver and to determine the safe upper limit of repeated intermittent hepatic inflow occlusion. METHODS: Hepatic ischemia in cirrhotic rats was induced by clamping the common pedicle of left and median lobes after non-ischemic lobes resection. The cirrhotic rats were divided into six groups according to the duration and form of vascular clamping: sham occlusion (SO), intermittent occlusion for 10 (IO-10), 15(IO-15), 20(IO-20) and 30(IO-30) minutes with 5 minutes of reflow and continuous occlusion for 60 minutes (CO-60). All animals received a total duration of 60 minutes of hepatic inflow occlusion. Liver viability was investigated in relation of hepatic adenylate energy charge (EC). Triphenyltetrazollum chloride (TTC) reduction activities were assayed to qualitatively evaluate the degree of irreversible hepatocellular injury. The biochemical and morphological changes were also assessed and a 7-day mortality was observed. RESULTS: At 60 minutes after reperfusion following a total of 60 minutes of hepatic inflow occlusion, EC values in IO-10 (0.749 +/- 0.012) and IO-15 (0.699 +/- 0.002) groups were rapidly restored to that in SO group (0.748 +/- 0.016), TTC reduction activities remained in high levels (0.144 +/- 0.002 mg/mg protein, 0.139 +/- 0.003 mg/mg protein and 0.121 +/- 0.003 mg/mg protein in SO, IO-10 and IO-15 groups, respectively). But in IO-20 and IO-30 groups, EC levels were partly restored (0.457 +/- 0.023 and 0.534 +/- 0.027) accompanying with a significantly decreased TTC reduction activities (0.070 +/- 0.005 mg/mg protein and 0.061 +/- 0.003 mg/mg protein). No recovery in EC values (0.228 +/- 0.004) and a progressive decrease in TTC reduction activities (0.033 +/- 0.002 mg/mg protein) were shown in CO-60 group. Although not significantly different, the activities of the serum aspartate aminotransferase (AST) on the third postoperative day (POD(3)) and POD(7) and of the serum alanine aminotransferase (ALT) on POD(3) in CO-60 group remained higher than that in intermittent occlusion groups. Moreover, a 60% animal mortality rate and more severe morphological alterations were also shown in CO-60 group. CONCLUSION: Hepatic inflow occlusion during 60 minutes for liver resection in cirrhotic rats resulted in less hepatocellular injury when occlusion was intermittent rather than continuous. Each period of 15 minutes was the safe upper limit of repeated intermittent vascular occlusion that the cirrhotic liver could tolerate without undergoing irreversible hepatocellular injury.

Dynamic changes in the collagen metabolism of liver fibrosis at the transcription level in rabbits with Schistosomiasis japonica

OBJECTIVE: To study the role of the synthesis and degradation of collagen at the transcription level during liver fibrogenesis due to schistosomiasis japonica in rabbits. METHODS: New Zealand rabbits challenged by cercariae of Schistosoma japonicum (S. japonicum) were served as animal models for liver fibrosis. Liver specimens were collected through operations at 4, 6, 8, 10, 12, 16, 20, 24 and 28 wks after challenge. Type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels of liver tissue were detected by RT-PCR + Dot blot. The size of egg granulomas and the degree of liver fibrosis were measured by histopathological examinations. RESULTS: Type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels increased simultaneously in the early stage after challenge. Most of them reached their peak at 10 weeks, and compared with normal controls, type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels increased by 12.0-, 11.0-, 6.6-, 10.0- and 11.0-fold, respectively, coinciding with the change of egg granulomas, i.e., the change in the inflammatory process. Then both collagen and collagenase mRNA levels decreased. Type I, III and IV collagen mRNA levels declined to 2-fold to 3-fold as compared with normal controls (P 0.05) at 28 wks. This study shows that the synthesis and degradation of collagen keep a dynamic balance at the early stage of schistosomiasis japonica challenge, while at the later stages the quantity of collagen synthesis was higher than that of collagen degradation. CONCLUSIONS: It was confirmed at transcription level that when the quantity of collagen synthesis was higher than that of collagen degradation liver fibrogenesis may be resulted in.