Comparative study of hepatoprotective action of remaxol, reamberin and ademethionine in liver injury induced by antituberculosis drugs (experimental study)

The hepatoprotective activity of remaxol, reamberin and ademethionine was studied on a model of the liver injury induced by antituberculosis drugs. The study included 30 male uninbred albino rats. The following antituberculosis drugs were used: isoniazid (50 mg/kg) subcutaneously + rifampicin (250 mg/kg) intragastrically + pyrazinamide (45 mg/kg) intragastically (by the procedure of Yu. I. Slivka, 1989). Remaxol, reamberin and ademethionine were administered 1.5 hour prior to the antituberculosis drugs. The treatment course was 14 days. It was shown that remaxol, reamberin and ademethionin were able to correct the structural and functional disorders in the liver due to the use of the antituberculosis drugs. By the impact on the biochemical indices, evident of the liver function condition, remaxol showed the maximum effect. The effect of ream-berin was somewhat lower and the results of the ademethionine use were less significant. Remaxol had also a distinct effect as for lowering the level of the structural injuries in the liver, evident from recovery of the organ histoarchitectonics, less extended carbohydrate, albuminous and fatty degeneration, more active intracellular regeneration. It was noted that ademethionine had an insignificant effect on necrobiosis. Moreover, there was once detected a large necrosis focus, evident of possible stimulation of the liver tissue alteration by the drug.     

Acceleration of the onset of liver regeneration by carnitine in partially hepatectomized rats

Immediately and 6 h after removal of 70% of the liver tissue, rats were treated with L-carnitine (Carnitene, Sigma-Tau, Italy) and received an injection of 100, 200 or 1,000 mg/kg b.w. into their femoral vein. The control rats were given the same volume of saline solution. The rats were sacrificed 18, 21, 24 or 30 h after the operation. The development of liver regeneration was evaluated from the incorporation of 14C-thymidine into DNA and from the hepatocyte mitiotic activity. In rats given carnitine in a dose of 100 or 200 mg/kg b.w. significantly higher DNA specific activity values were found 18 and 21 h after partial hepatectomoy and higher hepatocyte mitotic activity values after 30 h. In rats given carnitine in a dose of 1,000 mg/kg b.w., DNA specific activity values 21 h after partial hepatectomy were lower than in the control group. We conclude that L-carnitine, in a dose of 100 or 200 mg/kg b.w. has an enhancing effect on the onset of liver regeneration after 70% hepatectomy.     

大革耳子实体多糖抗氧化活性

作者对大革耳子实体多糖的抗氧化能力及单糖组分进行了分析,并探究了大革耳子实体多糖体外对羟自由基、超氧阴离子自由基、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基、2'-联氨-双-3-乙基苯并噻唑啉-6-磺酸[2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid),ABTS]自由基的清除能力和铁离子还原能力;以人正常肝细胞系LO2为材料建立了过氧化氢细胞氧化损伤模型,并探讨大革耳子实体多糖在细胞水平的抗氧化能力;通过苯酚硫酸法及HPLC检测了子实体多糖的单糖含量及组分。体外化学抗氧化实验结果显示,大革耳子实体多糖对羟自由基、超氧阴离子、DPPH自由基和ABTS自由基的清除能力较强,且具有较高的铁离子还原能力;细胞水平抗氧化实验表明,大革耳子实体多糖对人正常肝细胞系LO2的H₂O₂氧化损伤具有显著的保护作用,并能极显著提高受损细胞内过氧化氢酶（catalase,CAT）（P<0.01）及超氧化物歧化酶（superoxide dismutase,SOD）（P<0.01）的活力。大革耳子实体活性多糖主要单糖含量及组分依次为：葡萄糖（2 985.50mg/kg）、甘露糖（1 867.23mg/kg）、木糖（814.98mg/kg）、半乳糖（724.24mg/kg）、岩藻糖（443.72mg/kg）、葡萄糖醛酸（419.41mg/kg）、鼠李糖（81.18mg/kg）、阿拉伯糖（64.40mg/kg）、核糖（39.95mg/kg）、半乳糖醛酸（24.40mg/kg）。本研究结果为更好的推广应用和科学开发大革耳提供了基础资料。     

Hepatoprotective activity of Haridradi ghrita on carbon tetrachloride-induced liver damage in rats

Haridradi ghrita, a ghee based polyherbal formulation, (50, 100, 200 and 300 mg/kg) significantly lowered marker enzymes (SGPT, SGOT, ALP) and bilirubin in serum and liver peroxide, superoxide dismutase and catalase in liver homogenate following CCl4 (0.7 ml/kg, ip) toxicity. The protective effect was further supported by reversal of CCl4 induced histological changes. The results demonstrate significant hepatoprotective action of H. ghrita in CCl4 damaged rats.     

Long- and medium-chain triacylglycerols in nutritional support of liver regeneration of partially hepatectomized rats

An appropriate choice for a suitable diet during liver regeneration still remains an enigma. To investigate the effect of isocaloric enteral feeding with medium-chain triacylglycerols (MCT) and long-chain triacylglycerols (LCT) supplement (MCT+LCT, 40%:60% w:w) (178 kJ/kg b.w./24 h), rat liver regeneration was studied 24 and 72 h after partial hepatectomy. The liver DNA synthesis 24 h after partial hepatectomy was significantly higher in the MCT+LCT-supplemented rats (30.2+/-8.2 x 10(3) dpm/mg liver DNA) compared to MCT-treated animals (18.1+/-5.7 x 10(3) dpm/mg liver DNA). Liver protein synthesis was non-significantly elevated both 24 and 72 h after surgery in MCT+LCT-supplemented rats (13.7+/-1.1 and 10.9+/-3.1 x 10(3) dpm/mg liver protein). Seventy-two hours after partial hepatectomy, the hepatocyte mitotic activity was significantly increased in MCT+LCT- supplemented group vs. LCT- or MCT-fed rats (3.3+/-0.7 vs. 1.9+/-0.7 or 1.0+/-0.6 mitoses per 1000 hepatocytes), thus exhibiting an increased proliferative potential. The results showed a qualitative difference according to the proportion of MCT to LCT in the enteral supplements. Overfeeding with MCT decreased body weight, increased liver weight by its fatty infiltration, increased rat mortality rate and reduced spontaneous caloric intake. We conclude that the balanced supplement of MCT+LCT (40%:60% w:w) preserves liver regeneration, whereas overfeeding with MCT seems to be deleterious.     

Pathophysiological consequences of enhanced intracellular superoxide formation in isolated perfused rat liver.

The potential toxicity of enhanced intracellular reactive oxygen formation was investigated in isolated perfused livers of male Fischer rats. The presence of the redox-cycling agent diquat in the perfusate (200 microM) increased the basal efflux of glutathione disulfide (GSSG) into bile (2.65 +/- 0.26 nmol GSH-equivalents/min per g liver wt.) and perfusate (0.55 +/- 0.15 nmol/min per g) approximately 10-fold. Since no evidence was found for degradation of GSSG in the biliary tract of these animals, it could be estimated that diquat induced a constant O2- generation of approximately 1000 nmol/min per g liver wt for 1 h. Thus, reactive oxygen formation under these conditions was 1-2 orders of magnitude higher than under various pathophysiological conditions. Only minor liver injury (release of lactate dehydrogenase activity) was observed. To increase the susceptibility of the liver to the oxidant stress, animals were pretreated in vivo with 200 mg/kg body wt. phorone, which caused a 90% depletion of the hepatic glutathione content, 100 mg/kg ferrous sulfate, a combination of phorone and ferrous sulfate, or 40 mg/kg BCNU, which caused a 60% inhibition of hepatic GSSG reductase. Only the combined treatment of phorone + ferrous sulfate or BCNU caused a significant increase of the diquat-induced liver injury. Our results demonstrated an extremely high resistance of the liver against intracellular reactive oxygen formation (even with impaired detoxification systems) and can serve as reference for the evaluation of potential contributions of reactive oxygen to liver injury in various disease states.     

Mitigation of Acute Aluminum Toxicity by Sodium Selenite and N-Acetylcysteine in Adult Male Rats

The objective of this study is to investigate the toxic effects of aluminum and the potential alleviation of selenite and N-acetylcysteine (NAC) on this toxicity. Acute aluminum toxicity was induced by intraperitoneal (i.p.) injection of AlCl₃ (30 mg Al³⁺/kg) for four consecutive days. Al³⁺ damaged the synthetic capability and regeneration power of liver cells and induced inflammation. It also damaged the kidney and disturbed the lipid profile enhancing the total cholesterol level and LDL-cholesterol level increasing the risks of atherosclerosis. Al³⁺ reduced the cellular antioxidant milieu typified by the decrease in reduced glutathione, vitamin E, and four antioxidant enzymes and induced lipid peroxidation (LPO). Selenite at 1 mg Se/kg and NAC at 150 mg/kg injected either simultaneously with or after Al³⁺ mitigated most of these damaging effects probably by the virtue of scavenging the free radicals, binding aluminum and stimulating its excretion and reducing its bioavailability, bolstering the endogenous antioxidant defense systems, stabilizing the cell membrane, and preventing LPO. The beneficial effects of selenite and NAC against aluminum toxicity were also confirmed by the light and electron histopathology study. There were no significant differences between the two regimens used (protection and therapeutic) in the current study probably due to the short time of exposure, and the abrogation of Al³⁺ toxicity offered by selenite was better than that provided by NAC on the histopathology level.     

Regulation of polyamine synthesis in human hepatocytes by hepatotrophic factor augmenter of liver regeneration

Different stages of liver regeneration are regulated by a variety of factors such as the liver growth associated protein ALR, augmenter of liver regeneration. Furthermore, small molecules like polyamines were proven to be essential for hepatic growth and regeneration. Therefore, using primary human hepatocytes in vitro we investigated the effect of ALR on the biosynthesis of polyamines. We demonstrated by HPLC analysis that recombinant ALR enhanced intracellular hepatic putrescine, spermidine, and spermine levels within 9-12h. The activation of polyamine biosynthesis was dose dependent with putrescine showing the strongest increase. Additionally, ALR treatment induced mRNA expression of ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase, both key enzymes of polyamine biosynthesis. Further, ALR induced c-myc mRNA expression, a regulator of ODC expression, and therefore we assume that ALR exerts its liver regeneration augmenting effects through stimulation of its signalling pathway leading in part to enhanced polyamine synthesis.     

采用SCGE和SCE分析法研究姬松茸菌体多糖(Ab-Mp)对DNA损伤的抑制作用

热水浸提法提取姬松茸菌丝体多糖,每天以10mg/(kg bw)和20mg/(kg bw)两种剂量对小鼠进行灌胃,连续15d.腹腔注射环磷酰胺(CP),运用单细胞凝胶电泳(SCGE)法和姐妹染色体交换(SCE)分析法,研究Ab-Mp对染色体损伤的保护作用.结果表明,Ab-Mp降低了CP损伤后彗星细胞的比例,缩短了彗星尾长;降低了CP损伤的姐妹染色单体交换率.Ab-Mp对环磷酰胺诱发的DNA损伤具有拮抗作用.     

Modulation of balance between apoptosis and proliferation by lipid peroxidation (LPO) during rat liver regeneration

BACKGROUND: This work aims to investigate the role of lipid peroxidation (LPO) at early stages of liver regeneration and to evaluate the balance between apoptosis and cell proliferation during this process. METHODS: Sham and partial hepatectomized (PH) male Wistar rats were randomized in seven groups: Control (untreated), E-Control (injected with vitamin E-vehicle), C-Control (injected with vitamin C-vehicle), E1 (vitamin E 100 mg/kg body weight), E2 (vitamin E 600 mg/kg body weight), C1 (vitamin C 30 mg/kg body weight), C2 (vitamin C 100 mg/kg body weight). RESULTS: Vitamin treatments attenuated the increase of LPO level observed in total homogenate and microsomes at 3 and 5 hr after PH. Both antioxidant vitamins attenuated the increase in Bax pro-apoptotic protein and augmented Bcl-xL antiapoptotic protein levels (35%) at 3 and 5 hr post-PH; Bcl-xL/Bax ratio was, therefore, increased. A direct linear relationship between LPO levels and Bax mitochondrial protein levels was seen. Vitamin-treatments diminished the apoptosis index with respect to PH-Control values, so that this parameter showed a linear relationship with LPO levels. At 24 hr after PH, the vitamin treatments increased the peak of [(3) H]-thymidine incorporation into DNA and the proliferative index (PI), measured as PCNA expression; an inverse relationship between PI and LPO levels could be demonstrated. CONCLUSION: Our data show that the diminution of LPO levels by vitamin-treatment post-PH produces both an attenuation of cellular apoptosis and a marked increase in the proliferation process, suggesting that the modulation of LPO has a role in liver regeneration process.     

Effect of cysteine hydrochloride and sulfate ion on morphological changes in the liver during chronic poisoning with yellow phosphorus

It has been demonstrated that intragastric administration of cysteine hydrochloride in a dose of 50 mg/kg and sodium sulfate in a dose of 25 mg/kg with reference to sulfate ion reduced the circulatory disturbances, dystrophic and sclerotic changes in the rat liver caused by intragastric administration of yellow phosphorus in a dose of 1 mg/kg. Administration of the drugs interfered with the development of liver cirrhosis, stimulated regeneration, raised the adaptive abilities of hepatocytes. Cysteine protected hepatocyte mitochondria from phosphorus and activated their function. Meanwhile sulfate ion favoured glycogen accumulation in the cytoplasm of hepatocytes; cysteine hydrochloride and sulfate ion increased the content of total protein and glycogen in the liver and exerted an activating and normalizing effect on the enzymes of fatty, and carbohydrate metabolism, oxidative and energy processes.     

Lack of liver injury in Wistar rats treated with the combination of isoniazid and rifampicin

Isoniazid (INH) can cause serious idiosyncratic liver injury. An animal model would greatly facilitate mechanistic studies, but it is essential that the mechanism in the model be similar to the liver injury that can occur in humans. We attempted to replicate a previous study in which Wistar rats treated with INH and rifampicin (RMP) developed liver injury, which was promising because of its delayed onset similar to the liver injury that can occur in humans. Wistar rats were treated with either a high dose of INH (150 mg/kg/day) or a combination of INH and RMP (75 mg/kg/day and 50 mg/kg/day, respectively) for up to 4 weeks. However, we did not observe any liver injury or evidence of an inflammatory infiltrate as had been reported; rather, we observed an increase in CTLA4-positive cells in the cervical lymph nodes as well as a decrease in serum CXCL1 and MCP-1. In short, we were unable to reproduce a previously reported model of delayed onset INH-induced liver injury in Wistar rats.     

Frequency of structural chromosome aberrations in the hepatocytes of rats exposed to polymeric 239Pu

Intravenous injection of polymeric 239Pu(IV) nitrate (166.5, 55.5 and 18.5 kBq/kg body mass) to Wistar rats was shown to produce biphase changes in the frequency of hepatocyte chromosome aberrations. The increase in the structural damages to chromosomes at later times of observation was a pronounced function of radiation dose. The absence of such a dependence at early times was evidently due to the elimination of damaged liver parenchyma cells.     

Melatonin reduces the increase in 8-hydroxy-deoxyguanosine levels in the brain and liver of kainic acid-treated rats

In the present study, the effect of melatonin on oxidative DNA damage induced by kainic acid (KA) treatment was investigated. 8-hydroxy-deoxyguanosine (8-OH-dG) is a main product of oxidatively damaged DNA and was used as the endpoint in these studies. The levels of 8-OH-dG were found to be elevated in the hippocampus and frontal cortex of rats treated with KA. These elevated levels were significantly reduced in animals that were co-treated with melatonin. Thus, there was no difference in 8-OH-dG levels in the brain of control rats compared to those treated with KA (10 mg/kg) plus melatonin (10 mg/kg). The levels of 8-OH-dG also increased in the liver of rats treated with KA. This rise in oxidatively damaged DNA was also prevented by melatonin administration. Melatonin's ability to reduce KA-induced increases in neural and hepatic 8-OH-dG levels presumably relates to its direct free radical scavenging ability and possibly to other antioxidative actions of melatonin.     

Ameliorative effect of Partysmart in rat model of alcoholic liver disease

Present study was designed to investigate the effect of polyherbal formulation PartySmart in experimental model of alcoholic liver disease in male Wistar strain rats. Alcohol plus fish oil were administered to animals for 8 weeks to induce liver injury. PartySmart was administered at doses of 250 and 500 mg/kg body weight. After 8 weeks, parameters such as liver weight, liver function serum markers alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) and lipid peroxidation were studied. Livers from all the groups were subjected for histological evaluation. Treatment with PartySmart at the dose of 500 mg/kg body weight showed significant reduction in the levels of serum ALT, AST and ALP with a decrease in liver weight as compared to ethanol-fed rats. A significant decrease was also observed in malondialdehyde levels following treatment with PartySmart at 500 mg/kg body weight. Histological profile of liver tissue in PartySmart-treated animals showed lesser vacuolar degeneration and intactness of hepatic architecture along with improved glycogen deposition as demonstrated by PAS staining. PartySmart ameliorated alcohol-induced liver injury by preventing cell membrane disturbances, reduction of oxidative stress by free radical scavenging and antioxidant activity and normalization of altered intracellular redox status. Thus, PartySmart can be beneficial in the treatment of alcohol-induced liver damage.     

Minoxidil, a K(ATP) channel opener, accelerates DNA synthesis following partial hepatectomy in rats

A large number of studies have reported the action of K(ATP) channel openers in accelerating the proliferation of hepatocytes and many other cell types in vitro. Few studies, however, have examined the proliferative effect of K(ATP) channel openers in vivo. The aim of this study was to determine whether the K(ATP) channel opener minoxidil accelerates liver regeneration after partial hepatectomy (PH) in vivo. Male Wistar rats underwent a 70% partial hepatectomy (PH) after receiving a subcutaneous injection of minoxidil (0.01 mg/kg or 0.03 mg/kg). Some of the rats were intravenously treated with 5-hydroxydecanoic acid (5-HD, 10 mg/kg) just before the minoxidil injection. Seventy-two hours after PH, DNA synthesis was immunohistochemically assessed by bromodeoxyuridine (BrdU) incorporation into the nuclei. Minoxidil induced significant and dose-dependent increase in the BrdU labeling index after PH, and 5-HD reversed this minoxidil-induced change. Minoxidil did not significantly affect the changes in liver weight and liver function after PH. The hepatic levels of prealbumin decreased by about 60% after PH and minoxidil inhibited the decrease. In conclusion, the K(ATP) channel opener minoxidil enhanced DNA synthesis after PH without affecting the liver function.     

Dehydroepiandrosterone (DHEA) facilitates liver regeneration after partial hepatectomy in rats

In this study we investigated whether or not liver regeneration is facilitated by dehydroepiandrosterone (DHEA) after partial (70%) hepatectomy in rats. Treatment with DHEA (300 mg/kg body weight) did not cause any significant increase in the expression ratio of proliferating cell nuclear antigen (PCNA) in sham-operated controls; however, in partially hepatectomized rats it caused a significant increase in the ratio in hepatocytes 24 and 36 hr after hepatectomy. In partially hepatectomized rats, DHEA treatment significantly accelerated the restoration of liver 48, 60, and 72 hr after partial hepatectomy. The restoration rate in DHEA-treated hepatectomized rats at 72 hr was 1.3-fold greater than in partially hepatectomized controls. Treatment with androstenedione (300 mg/kg body weight), the first metabolite of DHEA, did not cause any significant increase in the expression of PCNA in either sham-operated controls or partially hepatectomized rats. These results indicate that DHEA itself promotes the liver regenerative process after partial hepatectomy in rats.     

Effect of dietary fluoride on selenite toxicity in the rat

Three factorial experiments were conducted to determine if high dietary fluoride (F) would inhibit selenite toxicity in rats. Initially, three levels of selenite (0.05, 3, and 5 mg/kg diet) were matched against three levels of F (2, 75, and 150 mg/kg diet). Fluoride failed to prevent the depressive effect of selenite on 8-wk food intake and body wt gain. Selenium (Se) concentration of plasma and kidney and enzymatic activity of whole blood glutathione peroxidase (GSH-Px) were also unaffected by F. Liver Se concentration, however, was slightly (12%) but significantly (p<0.025) reduced when the highest F and Se levels were combined. Fluoride (150 mg/kg) appeared to reduce liver selenite toxicity (5 mg/kg). Therefore, further study focused on liver histology with treatments that eliminated the middle levels of selenite and F. Fluoride prevented the hepatic necrosis seen in selenite-toxic rats. Similar histological lesions were not observed for kidney or heart. Fluoride partially (26%) but significantly (p<0.025) reduced thiobarbituric-reactive substances in selenite-toxic rats, but there was no F effect on intracellular distribution of liver Se, glutathione levels in liver and kidney, or on liver xanthine oxidase activity. Overall, the protective effect of F on selenite toxicity appears to be confined to liver pathology. The exact mechanism for this effect, however, remains unclear. Oregon Agricultural Experiment Station Technical Paper No. 9728.     

Cumulation of mycotoxins in maize cobs infected with<Emphasis Type="Italic">Fusarium gramihearum</Emphasis>

Maize cobs withFusarium ear rot were collected at 1986 season and five infected byFusarium graminearum were analyzed for presence of triohothecenes and zearalenone. Collected material was subsampled forFusarium damaged kernels and corresponding axial stems and healthy looking kernels. All investigated cobs contained deoxynivalenol (DON) (range 18.0–131.5 mg/kg) and zearalenone (ZEA) (range 0.38–2.17 mg/kg), in four cobs 15-acetyl-deoxynivalenol (15-AcDON) (range 5.2–6.2 mg/kg) was present and two cobs besides three all metabolites contained 3-acetyl-deoxynivalenol (3-AcD0N) (range 0.5–0.8 mg/kg).The average of individual toxins amount in axial stems: in mg/kg was equal to: DON — 110.36, ZEA — 4.57, 15-AcD0N — 16.66, and 3-AcD0N — 1.32.Fusarium damaged kernels contained in average the following amount (mg/kg) of: DON 77.00, ZEA 0.98, 15-AcD0N 3.78 and 3-AcD0N 0.06. Healthy looking kernels contained DON 1.96 mg/kg and ZEA 0.07 mg/kg only. Cooccurrence of 3-AcDON and 15-AcDON in two samples was an interesting finding. The amount of DON in total cob was highly correlated (r = 0.94) with percentage ofFusarium damaged kernels in given ear.     

Effect of glucocorticoids on alpha-fetoprotein synthesis and liver structure in mice acutely poisoned with carbon tetrachloride]

Experiments on male C57BL mice demonstrated that the CCl4 inhalation for 15 minutes in a concentration of 0.05 ml to 4 l of air caused deep dystrophic lesions of the liver with the signs of necrobiosis. The signs of regeneration and cellular infiltration appeared almost in 24 hours accompanied by the secretion of alpha-fetoprotein into the blood. The foci of necrobiosis disappeared completely in 4 days, being replaced by the lymphoid cells with large hepatocytes in the circumference. In the animals given hydrocortisone (20 mg/kg) or dexamethasone (2 mg/kg) for therapeutic or prophylactic purpose the regenerative processes were decreased, and the number of animals producing alpha-fetoproteins fell from 92 to 60--65%.