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Clemens MM, McGill MR, Apte U. Mechanisms and biomarkers of liver regeneration after drug-induced liver injury. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2019; 85:241-262. [PMID: 31307589 DOI: 10.1016/bs.apha.2019.03.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Liver, the major metabolic organ in the body, is known for its remarkable capacity to regenerate. Whereas partial hepatectomy (PHx) is a popular model for the study of liver regeneration, the liver also regenerates after acute injury, but less is known about the mechanisms that drive it. Recent studies have shown that liver regeneration is critical for survival in acute liver failure (ALF), which is usually due to drug-induced liver injury (DILI). It is sometimes assumed that the signaling pathways involved are similar to those that regulate regeneration after PHx, but there are likely to be critical differences. A better understanding of regeneration mechanisms after DILI and hepatotoxicity in general could lead to development of new therapies for ALF patients and new biomarkers to predict patient outcome. Here, we summarize what is known about the mechanisms of liver regeneration and repair after hepatotoxicity. We also review the literature in the emerging field of liver regeneration biomarkers.
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Affiliation(s)
- Melissa M Clemens
- Interdisciplinary Biomedical Sciences Graduate Program, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Mitchell R McGill
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR, United States; Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, United States.
| | - Udayan Apte
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS, United States
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Faroon OM, Mehendale HM. Bromotrichloromethane Hepatotoxicity. The Role of Stimulated Hepatocellular Regeneration in Recovery: Biochemical and Histopathological Studies in Control and Chlordecone Pretreated Male Rats. Toxicol Pathol 2016. [DOI: 10.1177/01926233900184p205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It has been shown that BrCCl3 is a more potent hepatotoxin than CCl4. Pretreatment with nontoxic dietary levels of chlordecone (CD) results in amplification of BrCCl3 hepatotoxicity. The objective of this research was to investigate and compare the histopathological alterations during a time course after a low dose of BrCCl3 alone and in combination with dietary CD. Male Sprague-Dawley rats were maintained on 10 ppm dietary CD or normal diet for 15 days. On day 16, they received a single ip dose (30 μ1/kg) of BrCCl3 in corn oil (CO) vehicle or corn oil alone. Blood and liver samples were collected at 0, 3, 6, 12, 24, 36, 48, 72, 96, and 120 hr for serum enzymes and histopathological examination, respectively. Serum enzymes (SDH, ALT, AST) were significantly ( p < 0.05) elevated in rats receiving the CD + BrCCl3 combination in comparison to BrCCl3 alone. For 48 hr, a continuous increase in serum enzyme activities was detected in rats treated with CD + BrCCl3 combination, but not in the rats receiving other treatments (ND + BrCCl3, ND + CO, or CD + CO). The most extensive hepatolobular necrosis was observed in rats treated with the CD + BrCCl3 combination. Thirty-six hr after the administration of BrCCl3 to rats maintained on normal diet, high mitotic activity was observed, which continued through 72 hr resulting in complete restoration of hepatolobular structure. In contrast, rats receiving the combination of CD + BrCCl3 exhibited minimal and belated hepatomitotic activity for a short period of time, resulting in progressive hepatic failure, culminating in animal death. In conclusion, hepatotoxicity of a low dose of BrCCl3 alone appeared to be overcome via stimulated hepatocellular regeneration and hepatolobular restoration. CD appears to amplify BrCCl3 hepatotoxicity via interference with this hormetic mechanism, permitting a progressive and continued hepatic injury leading to complete hepatic failure, culminating in animal death.
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Affiliation(s)
- Obaid M. Faroon
- Department of Pharmacology and Toxicology, University of Mississippi Medical
Center, Jackson, Mississippi 39216-4505
| | - Harihara M. Mehendale
- Department of Pharmacology and Toxicology, University of Mississippi Medical
Center, Jackson, Mississippi 39216-4505
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Anti-fibrotic and anti-inflammatory effects of parboiled germinated brown rice ( Oryza sativa ‘KDML 105’) in rats with induced liver fibrosis. J Funct Foods 2016. [DOI: 10.1016/j.jff.2016.08.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Abstract
Dietary restriction (DR) also called dietary control or calorie restriction is reported to have many advantages with regard to human health. It leads to suppression of obesity, mitigates free radicals and increases available antioxidants which are accounted for extending the life span of individuals. DR is also reported to induce synthesis of heat shock proteins in animals as a control mechanism against stress. Further, it is known to play a significant role in decreasing toxicity and lethality due to a variety of toxic chemicals and drugs by stimulating tissue repair damaged by the toxicants leading to restoration of intact organ and its functions. Moreover, extensive work done on animals indicate DR has an important role in suppressing certain types of cancer. In this review an effort is made to highlight the various advantages of DR from the point of human health perspective.
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Affiliation(s)
- M N Astagimath
- Department of Biochemistry, Kasturba Medical College, 575 004 Bejai, Mangalore
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Vollmar B, Menger MD. The hepatic microcirculation: mechanistic contributions and therapeutic targets in liver injury and repair. Physiol Rev 2009; 89:1269-339. [PMID: 19789382 DOI: 10.1152/physrev.00027.2008] [Citation(s) in RCA: 355] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The complex functions of the liver in biosynthesis, metabolism, clearance, and host defense are tightly dependent on an adequate microcirculation. To guarantee hepatic homeostasis, this requires not only a sufficient nutritive perfusion and oxygen supply, but also a balanced vasomotor control and an appropriate cell-cell communication. Deteriorations of the hepatic homeostasis, as observed in ischemia/reperfusion, cold preservation and transplantation, septic organ failure, and hepatic resection-induced hyperperfusion, are associated with a high morbidity and mortality. During the last two decades, experimental studies have demonstrated that microcirculatory disorders are determinants for organ failure in these disease states. Disorders include 1) a dysregulation of the vasomotor control with a deterioration of the endothelin-nitric oxide balance, an arterial and sinusoidal constriction, and a shutdown of the microcirculation as well as 2) an overwhelming inflammatory response with microvascular leukocyte accumulation, platelet adherence, and Kupffer cell activation. Within the sequelae of events, proinflammatory mediators, such as reactive oxygen species and tumor necrosis factor-alpha, are the key players, causing the microvascular dysfunction and perfusion failure. This review covers the morphological and functional characterization of the hepatic microcirculation, the mechanistic contributions in surgical disease states, and the therapeutic targets to attenuate tissue injury and organ dysfunction. It also indicates future directions to translate the knowledge achieved from experimental studies into clinical practice. By this, the use of the recently introduced techniques to monitor the hepatic microcirculation in humans, such as near-infrared spectroscopy or orthogonal polarized spectral imaging, may allow an early initiation of treatment, which should benefit the final outcome of these critically ill patients.
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Affiliation(s)
- Brigitte Vollmar
- Institute for Experimental Surgery, University of Rostock, Rostock, Germany.
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Muntané J. Multiple beneficial actions of fructose 1,6-biphosphate in sepsis-associated liver injury*. Crit Care Med 2006; 34:927-9. [PMID: 16505691 DOI: 10.1097/01.ccm.0000202436.45295.6e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Al-Waili NS. Intravenous and Intrapulmonary Administration of Honey Solution to Healthy Sheep: Effects on Blood Sugar, Renal and Liver Function Tests, Bone Marrow Function, Lipid Profile, and Carbon Tetrachloride-Induced Liver Injury. J Med Food 2003; 6:231-47. [PMID: 14585190 DOI: 10.1089/10966200360716652] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Safety of intravenous (i.v.) or intrapulmonary administration of different concentrations of honey and their effects on blood sugar, renal and liver function tests, bone marrow function, lipid profile, and carbon tetrachloride (CCl(4))-induced liver damage were studied. Healthy sheep of either sex, 6-8 months old, were assigned randomly into the following groups: sheep received i.v. infusion of 5% honey in normal saline at 10-day intervals for 50 days and were compared with sheep that received 5% dextrose; sheep received higher doses of honey (50 g of honey) by i.v. infusion daily for 10 days; sheep received four higher doses of honey (80 g each dose) for 2 weeks; sheep received subcutaneous injection of CCl(4) after four doses of i.v. infusion of 80 g of honey, and estimations of serum gamma-glutamyl transpeptidase (SGGT), serum glutamic oxaloacetic transaminase (SGOT), and serum glutamate pyruvate transaminase (SGPT) were performed daily for 10 days postinjection; sheep received i.v. infusion of 40 g of honey, and blood sugar estimation was performed for 3 h at 30-min intervals after infusion and compared with sheep that received 5% dextrose; sheep received rapid i.v. injection of 40% honey or 40% dextrose, and blood sugar was estimated before and after injection; sheep received various concentrations of honey in distilled water (0.5 mL/1.5 mL, 0.75 mL/1.75 mL and 1.2 mL/2.2 mL), and blood sugar estimation was performed before and after inhalation. Results showed that i.v. or intrapulmonary administration of honey did not cause any adverse effect. Intravenous delivery of honey by slow infusion caused improvement of renal and hepatic function, bone marrow function, and lipid profile. It reduced SGOT, SGPT, triglyceride, cholesterol, blood urea nitrogen, and blood sugar and elevated serum protein, serum albumin, hemoglobin, white blood cell, and neutrophil percentage. Similar results were obtained with the use of higher doses of honey. CCl(4) caused mild elevation of SGPT and SGGT and lowering of SGOT in sheep that received repeated i.v. administration of honey before administration of CCl(4), whereas in control sheep CCl(4) caused significant elevation of all the liver enzymes. Intravenous infusion of 40 g of honey caused elevation of blood sugar for 90 min postinfusion, whereas it decreased blood sugar at 2 and 3 h postinfusion as compared with fasting blood sugar. Dextrose caused significant elevation of blood sugar at all time intervals. Similar results were obtained with the use of 10% dextrose or 80 g of honey. Addition of honey to dextrose caused less hyperglycemia as compared with dextrose alone. Acute injection of 20 mL of 40% dextrose significantly elevated blood sugar for 3 h postinjection, whereas little elevation in blood sugar was obtained after injection of 40% honey; the difference between honey and dextrose was significant. Inhalation of honey caused significant lowering of blood sugar during and after inhalation as compared with fasting blood sugar and water inhalation. The effect was greater with a higher concentration of inhaled honey. It might be concluded that slow i.v. infusion or rapid i.v. injection of honey in different concentrations was safe and could lower blood sugar and improve renal, hepatic, and bone marrow functions and lipid profile. Intravenous honey had a hepatoprotective effect against CCl(4)-induced liver injury. Inhaled honey was safe and reduced blood sugar significantly.
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Affiliation(s)
- Noori S Al-Waili
- Dubai Specialized Medical Center and Medical Research Laboratories, Islamic Establishment for Education, Dubai, United Arab Emirates.
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Nunes FB, Graziottin CM, Alves Filho JCF, Lunardelli A, Pires MGS, Wächter PH, De Oliveira JR. An assessment of fructose-1,6-bisphosphate as an antimicrobial and anti-inflammatory agent in sepsis. Pharmacol Res 2003; 47:35-41. [PMID: 12526859 DOI: 10.1016/s1043-6618(02)00255-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Tissue lesion mechanisms provoked by sepsis include the infectious process, inflammation, and cellular energy deficit. We chose to test fructose-1,6-bisphosphate (FBP) because of its possible anti-inflammatory and antimicrobial actions. Wistar rats were used and divided into three experimental groups: a control group (n=10), in which a capsule was introduced into the peritoneum of the animals; a septic group (n=10), in which a capsule containing non-sterile fecal matter was introduced together with Escherichia coli (1.5 x 10(9)CFU); and a septic group treated with FBP 500 mg/kg (n=10). The blood cell tests revealed that levels of leukocytes increased significantly in the septic group when compared to both the septic group treated with FBP and the control group. The blood cultures were 100% positive in both the septic group and the septic group treated with bisphosphorylated sugar. The antibiogram only revealed an inhibitory halo in the case of the antibiotic ampicillin, there was no such indication for FBP. The anti-inflammatory power of FBP remained at 60% for 5 h in the rats that received the carrageenan injection. What is more, the sugar reduced the levels of ionic calcium in relation to the control group. This data proves the validity of using FBP in the treatment of sepsis, possibly due to its anti-inflammatory rather than antimicrobial action.
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Affiliation(s)
- Fernanda B Nunes
- Laboratório de Pesquisa em Biofísica, Departamento de Ciências Fisiológicas, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Rio Grande do Sul 91530-170, Brazil.
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Nunes FB, Simões Pires MG, Alves Filho JCF, Wächter PH, Rodrigues De Oliveira J. Physiopathological studies in septic rats and the use of fructose 1,6-bisphosphate as cellular protection. Crit Care Med 2002; 30:2069-74. [PMID: 12352043 DOI: 10.1097/00003246-200209000-00020] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The aim of this research project was to test the ability of fructose 1,6-bisphosphate (FBP), which has anti-inflammatory effects and maintains cellular energy levels, to inhibit the septic process in an experimental model in rats. DESIGN Prospective, controlled animal trial. SETTING Research laboratory. SUBJECTS Fed male Wistar rats. INTERVENTIONS Three experimental groups were formed for the test: control group, untreated septic group, and septic group treated with FBP (500 mg/kg). MEASUREMENTS AND MAIN RESULTS In the control group, there were no deaths; in the untreated septic group, the mortality rate was 100% within 15 hrs; in the septic group treated with FBP, the mortality rate reached 20% within 15 hrs. The blood cell tests revealed that concentrations of hematocrit, leukocytes, monocytes, and immature cells increased significantly in the untreated septic group compared with both the FBP-treated septic group and the control group. The histologic lesions verified in the heart, lungs, liver, and kidneys of septic animals were smaller and even absent in those treated with FBP. CONCLUSION FBP reduced the mortality rate provoked by experimental sepsis and ameliorated hematologic and histologic alterations.
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Affiliation(s)
- Fernanda Bordignon Nunes
- Laboratório de Pesquisa em Biofísica, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Brazil
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Chu SJ, Chang DM, Wang D, Chen YH, Hsu CW, Hsu K. Fructose-1,6-diphosphate attenuates acute lung injury induced by ischemia-reperfusion in rats. Crit Care Med 2002; 30:1605-9. [PMID: 12130986 DOI: 10.1097/00003246-200207000-00034] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine whether fructose-1,6-diphosphate (FDP) pretreatment can attenuate acute lung injury induced by ischemia-reperfusion in our isolated lung model in rats. DESIGN Randomized, controlled study. SETTING Animal care facility procedure room. SUBJECTS Twenty-four adult male Sprague-Dawley rats each weighing 250-350 g. INTERVENTIONS Typical acute lung injury in rats was induced successfully by 10 mins of hypoxia followed by 75 mins of ischemia and 50 mins of reperfusion. Ischemia-reperfusion significantly increased microvascular permeability as measured by the capillary filtration coefficient, lung weight gain, lung weight to body weight ratio, pulmonary arterial pressure, and protein concentration of bronchoalveolar lav-age fluid. MEASUREMENTS AND MAIN RESULTS Pretreatment with FDP significantly attenuated the acute lung injury induced by ischemia-reperfusion as shown by a significant decrease in all of the assessed variables (p <.05 p <.001). The protective effect of FDP was nearly undetectable when promazine (an ecto-adenosine 5-triphosphatase inhibitor) was added before FDP pretreatment. CONCLUSIONS Pretreatment with FDP significantly ameliorates acute lung injury induced by ischemia-reperfusion in rats.
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Affiliation(s)
- Shi-Jye Chu
- Department of Emergency Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China.
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11
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Millo H, Werman MJ. Hepatic fructose-metabolizing enzymes and related metabolites: role of dietary copper and gender. J Nutr Biochem 2000; 11:374-81. [PMID: 11044632 DOI: 10.1016/s0955-2863(00)00093-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The purpose of this study was to further examine the hypothesis that variations in hepatic fructose-metabolizing enzymes between males and females might account for the differences in the severity of copper (Cu) deficiency observed in fructose-fed male rats. Weanling rats of both sexes were fed high-fructose diets either adequate or deficient in copper for 45 days. Cu deficiency decreased sorbitol dehydrogenase activity and dihydroxyacetone phosphate levels and increased glyceraldehyde levels in both sexes. Gender effects were expressed by higher activities of glycerol 3-phosphate dehydrogenase and aldehyde dehydrogenase in male than in female rats and higher levels of dihydroxyacetone phosphate and fructose 1,6-diphosphate (F1,6DP) in female than in male rats. The interactions between dietary Cu and gender were as follows: alcohol dehydrogenase activities were higher in female rats and were further increased by Cu deficiency in both sexes; aldehyde dehydrogenase activities were decreased by Cu deficiency only in male rats; sorbitol levels were higher in male rats and were further increased by Cu deficiency in male rats; fructose 1-phosphate (F1P) levels were increased by Cu deficiency in both sexes, but to a greater extent in male rats; glyceraldehyde 3-phosphate levels were higher in female rats, but were decreased by Cu deficiency in female and increased in male rats. Though most of the examined hepatic fructose-metabolizing enzymes and metabolites showed great differences between rats fed diets either adequate or deficient in Cu, it is the activity of fructokinase and aldolase-B, and the concentrations of their common metabolites, F1P and notably F1,6DP, that could be in part responsible for differences in the severity of pathologies associated with Cu deficiency observed between female and male rats.
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Affiliation(s)
- H Millo
- Department of Food Engineering and Biotechnology, Technion - Israel Institute of Technology, Haifa, Israel
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Soni MG, Mehendale HM. Role of tissue repair in toxicologic interactions among hepatotoxic organics. ENVIRONMENTAL HEALTH PERSPECTIVES 1998; 106 Suppl 6:1307-1317. [PMID: 9860886 PMCID: PMC1533468 DOI: 10.1289/ehp.98106s61307] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
It is widely recognized that exposure to combinations or mixtures of chemicals may result in highly exaggerated toxicity even though individual chemicals might not be toxic at low doses. Chemical mixtures may also cause additive or less than additive toxicity. From the perspective of public health, highly exaggerated toxicity is of significant concern. Assessment of risk from exposure to chemical mixtures requires knowledge of the underlying mechanisms. Previous studies from this laboratory have shown that nontoxic doses of chlordecone (10 ppm, 15 days) and carbon tetrachloride (CCl4) (100 microliters/kg) interact at the biologic interface, resulting in potentiated liver injury and 67-fold amplification of CCl4 lethality. In contrast, although interaction between phenobarbital and CCl4 leads to even higher injury, animal survival is unaffected because of highly stimulated compensatory tissue repair. A wide variety of additional experimental evidence confirms the central role of stimulated tissue repair as a decisive determinant of the final outcome of liver injury inflicted by hepatotoxicants. These findings led us to propose a two-stage model of toxicity. In this model, tissue injury is inflicted in stage one by the well-described mechanisms of toxicity, whereas in stage two the ultimate toxic outcome is determined by whether timely and sufficient tissue repair response accompanies this injury. In an attempt to validate this model, dose-response relationships for injury and tissue repair as opposing responses have been developed for model hepatotoxicants. Results of these studies suggest that tissue repair increases in a dose-dependent manner, restraining injury up to a threshold dose, whereupon it is inhibited, allowing an unrestrained progression of injury. These findings indicate that tissue repair is a quantifiable response to toxic injury and that inclusion of this response in risk assessment may help in fine-tuning prediction of toxicity outcomes.
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Affiliation(s)
- M G Soni
- Division of Toxicology, College of Pharmacy and Health Sciences, Northeast Louisiana University, Monroe 71209-0470, USA
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Martin FL, McLean AE. Comparison of protection by fructose against paracetamol injury with protection by glucose and fructose-1,6-diphosphate. Toxicology 1996; 108:175-84. [PMID: 8658536 DOI: 10.1016/0300-483x(95)03280-s] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have compared the protective effect of fructose in normal Ringer solution during the onset and progression of cell injury induced by paracetamol in rat liver slices with the protective effect of glucose and fructose-1,6-diphosphate. Liver slices obtained from phenobarbitone-induced and non-induced rats were used in a model in vitro system. Slices were exposed to 10 mM paracetamol for 120 min and then incubated without paracetamol in the presence or absence of protective agents for a further 240 min. Cell injury was quantified by measuring leakage of lactate dehydrogenase (LDH) and potassium (K+). Adenosinetriphosphate (ATP) levels were measured using the luciferin-luciferase bioluminescence assay. Addition of higher concentrations of glucose (10-50 mM) to Ringer solution were not found to result in protection at the end of incubation in paracetamol-treated slices obtained from phenobarbitone-induced rats. Neither did sucrose nor mannitol protect. However, exclusion of glucose from Ringer solution resulted in cell injury in paracetamol-treated slices obtained from non-induced rats. Methionine, a known antidote for paracetamol poisoning, failed to protect in this instances but fructose did protect. This suggests that the presence of a glycolytic substrate plays a crucial role in cell protection. Further evidence for this is the finding that iodoacetate, an inhibitor of glycolysis, not only increase cell injury in paracetamol-treated slices but also reverses fructose protection. Fructose-1,6-diphosphate was found to protect against the onset and progression of cell injury in paracetamol-treated slices obtained from phenobarbitone induced rats. This protective agent is found to maintain high ATP levels and cell viability in paracetamol-treated slices at a time when paracetamol-treated slices show a profound loss of ATP levels and a significant increase in cell injury as measured by leakage of LDH and K+.
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Affiliation(s)
- F L Martin
- Department of Medicine, University College London, UK
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Mehendale HM. Toxicodynamics of low level toxicant interactions of biological significance: inhibition of tissue repair. Toxicology 1995; 105:251-66. [PMID: 8571362 DOI: 10.1016/0300-483x(95)03220-a] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Because of the complexity of studying the toxicological effects of mixtures of chemicals, much of the mechanistic information has become available through work with binary mixtures of toxic chemicals. Mechanisms derived from studies employing chemicals at individually nontoxic doses are more useful than the mechanisms of interactive toxicity at high doses from the perspective of environmental and public health. Several examples of chemical combinations and interactive toxicity at low doses are now available. Chlordecone-potentiated halomethane hepatotoxicity, where suppression of cell division and tissue repair response permits very high amplification of CCl4 injury culminating in animal mortality, is one such model. Phenobarbital-potentiated CCl4 injury does not lead to animal mortality in spite of much higher liver injury in comparison to the chlordecone+CCl4 model. Much higher stimulation of tissue repair allows the animals to survive despite higher liver injury. Similar interactions have been reported between alcohols and halomethane toxicants. These and other studies have revealed that infliction of toxicant-induced injury is accompanied by a parallel but opposing tissue repair stimulation response which allows the animals to overcome that injury up to a threshold dose. Beyond this threshold, tissue repair response is both diminished and delayed allowing unrestrained progression of injury. Large doses of chemicals can be predictably lethal owing to these two latter effects on tissue repair. Dose-response paradigms in which tissue repair response is measured as a parallel but opposing effect to toxic injury might be useful in more precise prediction of the ultimate outcome of toxic injury in risk assessment. Autoprotection experiments with CCl4, thioacetamide, 2-butoxyethanol and related chemicals as well as heteroprotection against acetaminophen-induced lethality with thioacetamide are examples where tissue repair stimulation has been shown to rescue the animals from massive and normally lethal liver injury. The concept of toxicodynamic interaction between inflicted injury and stimulated tissue repair offers mechanistic opportunity to fine-tune other aspects of human health risk assessment procedure. Tissue repair mechanisms may also offer a mechanistic basis to explain species and strain differences as well as to more accurately assess inter-individual differences in human sensitivity to toxic chemicals. Because tissue repair is affected by nutritional status, assessment of risk from exposure to chemicals without attention to nutritional status may be misleading. Finally, the concept of using maximum tolerated doses (MTDs) in long-term toxicity studies such as cancer bioassays may need to be re-examined. MTDs might be predictably expected to maximally stimulate cell division and it is known that increased cell division is likely to lead to increased number of errors in DNA replication thereby predisposing these animals to cancer. It is clear that detailed studies of toxicodynamic interaction between tissue injury and stimulated tissue repair are likely to yield significant dividends in fine-tuning risk assessment.
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Affiliation(s)
- H M Mehendale
- Division of Toxicology, College of Pharmacy and Health Sciences, Northeast Louisiana University, Monroe 71209-0470, USA
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Sano W, Watanabe F, Tamai H, Furuya E, Mino M. Beneficial effect of fructose-1,6-bisphosphate on mitochondrial function during ischemia-reperfusion of rat liver. Gastroenterology 1995; 108:1785-92. [PMID: 7768384 DOI: 10.1016/0016-5085(95)90141-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND/AIMS Several groups have reported that administration of fructose-1,6-bisphosphate (FBP) reduces ischemic injury. The aim of this study was to determine the protective effect of FBP on the impairment of mitochondrial oxidative phosphorylation by ischemia-reperfusion injury in the rat liver. METHODS The respiratory control ratio (RCR) and the adenine nucleotide content of mitochondria isolated from ischemic and reperfused livers with or without FBP treatment were measured. RESULTS In FBP-treated livers, the cellular adenosine triphosphate level was restored to more than 50% of normal after 120 minutes of reperfusion following 120 minutes of ischemia, whereas that of control livers only reached 15% of normal. The RCR and the adenine nucleotide content of mitochondria isolated from FBP-treated livers were significantly higher than those of mitochondria from control livers after ischemia and reperfusion. FBP strongly suppressed the formation of lipid peroxides during reperfusion. In vitamin E-deficient rats, the RCR decreased markedly during reperfusion, but FBP protected the mitochondria against reperfusion injury. CONCLUSIONS FBP has a protective effect against ischemia-reperfusion injury on the liver and especially preserves the oxidative phosphorylation capacity of hepatic mitochondria.
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Affiliation(s)
- W Sano
- Department of Pediatrics, Osaka Medical College, Japan
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16
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Chlordecone-CCl4 interactive hepatotoxicity-suppression of hormesis and recovery. Indian J Clin Biochem 1994. [DOI: 10.1007/bf02869572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Mehendale HM. Amplified interactive toxicity of chemicals at nontoxic levels: mechanistic considerations and implications to public health. ENVIRONMENTAL HEALTH PERSPECTIVES 1994; 102 Suppl 9:139-49. [PMID: 7535226 PMCID: PMC1566795 DOI: 10.1289/ehp.94102s9139] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
It is widely recognized that exposure to combinations or mixtures of chemicals may result in highly exaggerated toxicity even though the individual chemicals might not be toxic. Assessment of risk from exposure to combinations of chemicals requires the knowledge of the underlying mechanism(s). Dietary exposure to a nontoxic dose of chlordecone (CD; 10 ppm, 15 days) results in a 67-fold increase in lethality of an ordinarily inconsequential dose of CCl4 (100 microliters/kg, ip). Toxicity of closely related CHCl3 and BrCCl3 is also enhanced. Phenobarbital (PB, 225 ppm, 15 days) and mirex (10 ppm, 15 days) do not share the propensity of CD in this regard. Exposure to PB + CCl4 results in enhanced liver injury similar to that observed with CD, but the animals recover and survive in contrast to the greatly amplified lethality of CD + CCl4. Investigations have revealed that neither enhanced bioactivation of CCl4 nor increased lipid peroxidation offers a satisfactory explanation of these findings. Additional studies indicate that exposure to a low dose of CCl4 (100 microliters/kg, ip) results in limited injury, which is accompanied by a biphasic response of hepatocellular regeneration (6 and 36 hr) and tissue repair, which enables the animals to recover from injury. Exposure to CD + CCl4 results in suppressed tissue repair owing to an energy deficit in hepatocytes as a consequence of excessive intracellular influx of Ca2+ leading initially to a precipitous decline in glycogen and ultimately to hypoglycemia. Supplementation of cellular energy results in restoration of the tissue repair and complete recovery from the toxicity of CD + CCl4 combination. In contrast, only the early-phase hepatic tissue repair (6 hr) is affected in PB + CCl4 treatment, but this is adequately compensated for by a greater stimulation of tissue repair at 24 and 48 hr resulting in recovery from liver injury and animal survival. A wide variety of additional experimental evidence confirms the central role of stimulated tissue repair as a decisive determinant of the final outcome of liver injury inflicted by CCl4. For instance, a 35-fold greater CCl4 sensitivity of gerbils compared to rats is correlated with the very sluggish tissue repair in gerbils. These findings are consistent with a two-stage model of toxicity, where tissue injury is inflicted by the well described "mechanisms of toxicity," but the outcome of this injury is determined by whether or not sustainable tissue repair response accompanies this injury.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- H M Mehendale
- Division of Pharmacology and Toxicology, College of Pharmacy and Health Sciences, Northeast Louisiana University, Monroe 71209-0470
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18
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Roig T, De Oliveira JR, Bartrons R, Bermúdez J. Fructose 1,6-bisphosphate protects against D-galactosamine toxicity in isolated rat hepatocytes. THE AMERICAN JOURNAL OF PHYSIOLOGY 1994; 266:C1722-8. [PMID: 8023901 DOI: 10.1152/ajpcell.1994.266.6.c1722] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Incubation of hepatocytes with D-galactosamine (GalN) produced a dose-dependent alteration in cell viability and a fall in ATP and fructose 2,6-bisphosphate (Fru-2,6-P2) levels. The reduction in Fru-2,6-P2 can be explained by changes in the substrates or modulators of 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase, because neither the adenosine 3',5'-cyclic monophosphate level nor the activity ratio of the enzyme was modified. Microcalorimetric measurements showed that GalN produced an exothermic peak followed by a progressive decrease in heat dissipation. Simultaneous administration of GalN and fructose 1,6-bisphosphate (Fru-1,6-P2) significantly increased cell viability, and concentrations of ATP and Fru-2,6-P2 and led to stable heat production. In the presence of Fru-1,6-P2 alone, hepatocytes kept ATP and Fru-2,6-P2 levels constant, whereas they increased the oxygen uptake-to-heat output ratio. Our results suggest that GalN initiates the hepatotoxic effect by means of an energy-dissipating interaction, produced before its metabolism and presumably at the membrane level, whereas Fru-1,6-P2 protects the cells against this injury in a way that prevents the initial interaction and increases the metabolic efficiency of the cell.
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Affiliation(s)
- T Roig
- Unitat de Biofísica, Facultat d'Odontologia, Universitat de Barcelona, Spain
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19
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Abstract
Dietary exposure to a nontoxic level of chlordecone (10 ppm for 15 days) followed by a single exposure to a subtoxic dose of CCl4 (100 microliters/kg, ip) is known to result in a 67-fold amplification of CCl4 toxicity. The hypothesis that the underlying mechanism is due to incapacitation of hepatocytes leading to an ablation of the early-phase hormetic response of tissue repair as a consequence of precipitous decline in hepatic glycogen and ATP, received experimental support from Mehendale in 1990. The present study was designed to investigate if direct administration of ATP to rats maintained on the chlordecone diet would result in protection from the hepatotoxic and lethal effects of the chlordecone+CCl4 combination. Male Sprague-Dawley rats (125-150 g) were maintained either on a diet containing no added contaminants (control) or on a diet containing 10 ppm chlordecone for 15 days, and were challenged with CCl4 (100 microliters/kg, ip) on day 16. Without ATP administration all rats died within 72 h, while administration of ATP (100 mg/rat, sc) to chlordecone-pretreated rats at -1, +1, 3, 5, 12, 24 and 36 h of CCl4 injection resulted in 100% survival. Injection of ATP, at -1, +1, 3 and 5 h of CCl4 administration to chlordecone pretreated rats decreased plasma enzyme elevations (alanine and aspartate aminotransferase, sorbitol dehydrogenase) as well as substantially preventing elevation of plasma bilirubin levels at 6, 12 and 24 h. Hepatic ATP levels were also elevated at 6 and 12 h, but not at 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M G Soni
- Division of Pharmacology & Toxicology, College of Pharmacy and Health Sciences, Northeast Louisiana University, Monroe 71209-0470
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20
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Rigobello MP, Galzigna L, Bindoli A. Fructose 1,6-bisphosphate prevents oxidative stress in the isolated and perfused rat heart. Cell Biochem Funct 1994; 12:69-75. [PMID: 8168233 DOI: 10.1002/cbf.290120110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rat hearts were perfused with the Langendorff technique at constant flux in the presence of the oxidizing agents hydrogen peroxide and diamide. Fructose 1,6-bisphosphate strongly prevented the decline of heart contractility due to the infusion of these oxidizing agents. On the other hand, fructose 1,6-bisphosphate had no effect on the release of total glutathione into the perfusate but prevented the loss of lactate dehydrogenase indicating a protective effect on cell membranes. Comparing the cytosolic and mitochondrial loss of glutathione, fructose 1,6-bisphosphate exerted a beneficial action only on the mitochondrial fraction. Several mechanisms of action have been considered to explain the protective action of fructose 1,6-bisphosphate. In our experimental conditions fructose 1,6-bisphosphate might stimulate its own production giving rise to dihydroxyacetone phosphate, that, after reduction to glycerol 3-phosphate, can permeate the mitochondrial membrane with the final production of energy.
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Affiliation(s)
- M P Rigobello
- Dipartimento di Chimica Biologica, Università di Padova, Italy
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21
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Planas ME, Sánchez S, González P, Rodrigues de Oliveira J, Bartrons R. Protective effect of fructose 1,6-bisphosphate against carrageenan-induced inflammation. Eur J Pharmacol 1993; 237:251-5. [PMID: 8365453 DOI: 10.1016/0014-2999(93)90276-n] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Administration of carrageenan (0.5 mg) to the plantar tissue of rats resulted in reversible inflammatory injury. This damage was monitored as changes in foot volume, using a plethysmometer. Administration of fructose 1,6-bisphosphate at different doses, orally or intraperitoneally, prevented the inflammatory action induced by the simultaneous injection of carrageenan in the rat paw. The effect was dose and time dependent. In contrast, fructose or fructose 6-phosphate afforded no significant protection. In order to extend the average half-life of the drug, we prepared liposomes of fructose 1,6-bisphosphate which, administered orally or intraperitoneally, showed a greater and more prolonged antiinflammatory action. The significance of these findings with respect to the mechanism of the antiinflammatory action of fructose 1,6-bisphosphate is discussed.
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Affiliation(s)
- M E Planas
- Unitat de Farmacologia, Facultat Odontologia, Universitat de Barcelona, Hospitalet, Spain
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22
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De Oliveira JR, Rosa JL, Ambrosio S, Bartrons R. Effect of galactosamine on hepatic carbohydrate metabolism: protective role of fructose 1,6-bisphosphate. Hepatology 1992; 15:1147-53. [PMID: 1317340 DOI: 10.1002/hep.1840150628] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Intraperitoneal administration of galactosamine (400 mg/kg body wt) to rats results in reversible liver cell injury that is related to a dose-dependent depletion of uridine phosphates by formation of UDP-sugar derivatives. This damage was monitored through changes in serum enzymatic activities that increased after the first 6 hr of drug administration. Glycemia and serum albumin remained stable during liver injury, whereas cholesterol and triglycerides decreased. To maintain plasma glucose concentration, the hepatic carbohydrate metabolism was greatly altered. Glycogen dropped during the first hours, remaining low for up to 48 hr. Fructose 2,6-bisphosphate and ATP levels decreased even faster than glycogen, with lactate following a similar diminution and being restored in parallel with both metabolites. The reduction in fructose 2,6-bisphosphate can be explained by changes in the substrates or modulators of the 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase, because neither the cyclic AMP levels nor the activity ratio of the enzyme were modified. Simultaneous administration of galactosamine and fructose 1,6-bisphosphate (2 gm/kg) prevented liver cell death, as monitored by serum enzyme activities. Furthermore, the bisphosphorylated metabolite had protective effects on the changes in liver calcium content and ATP and fructose 2,6-bisphosphate concentrations. In contrast, fructose, fructose-1-phosphate and fructose-6-phosphate had no significant protection. Fructose 1,6-bisphosphate might decrease galactosamine toxicity by increasing fructose 2,6-bisphosphate and ATP levels, the changes in both metabolites probably being related. The significance of these findings with respect to the mechanism of galactosamine-induced liver injury is also discussed.
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Affiliation(s)
- J R De Oliveira
- Unitat de Bioquímica, Facultat Odontologia, Zona Universitària de Bellvitge, L'Hospitalet, Spain
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23
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Tavazzi B, Starnes JW, Lazzarino G, Di Pierro D, Nuutinen EM, Giardina B. Exogenous fructose-1,6-bisphosphate is a metabolizable substrate for the isolated normoxic rat heart. Basic Res Cardiol 1992; 87:280-9. [PMID: 1520250 DOI: 10.1007/bf00804337] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Isolated rat hearts were perfused by the recirculating Langendorff mode under normoxic conditions for 60 min. The Krebs-Ringer buffer was supplemented with 10 mM glucose + 12 IU/l insulin and either [U-14C]-fructose-1,6-bisphosphate (together with 5 mM cold fructose-1,6-bisphosphate) or [U-14C]-fructose (together with 5 mM cold fructose). At the end of perfusion, gaseous 14CO2, 14CO2 trapped in the perfusates, 14C-lactate output and tissue 14C-lactate were assayed in both groups of hearts. Analysis of high-energy compounds, glycogen, lactate, and pyruvate was also performed on the neutralized perchloric acid extracts of the freeze-clamped hearts. Data obtained from the 14C catabolites, originating from the metabolism of the radiolabeled substrates, indicated that the isolated normoxic rat heart metabolizes an 8.5 times higher amount of fructose-1,6-bisphosphate (7.07 mumoles/min/g d.w.) than of fructose (0.83 mumoles/min/g d.w.). CrP, CrP/Cr, glycogen, and total lactate in both tissue and perfusate were significantly higher in fructose-1,6-bisphosphate-perfused hearts. The overall indication is that fructose-1,6-bisphosphate can be taken up in its intact form by myocytes and successively metabolized to support their energy demand, and that its effects on myocardial performance and metabolism should be attributed to the molecule itself rather than to its eventual degradation products.
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Affiliation(s)
- B Tavazzi
- Department of Experimental Medicine and Biochemical Sciences, II University of Rome, Tor Vergata, Italy
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24
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Lazzarino G, Tavazzi B, Di Pierro D, Giardina B. Ischemia and reperfusion: effect of fructose-1,6-bisphosphate. FREE RADICAL RESEARCH COMMUNICATIONS 1992; 16:325-39. [PMID: 1505790 DOI: 10.3109/10715769209049185] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Several lines of evidence indicating a close relationship among ischemia, concentration of high-energy metabolites and onset of the "oxygen paradox" in reperfused tissues have been published. In this framework, we have recently studied the effects of exogenous fructose-1,6-bisphosphate on energy metabolism and on oxygen free radical damages of isolated rat heart subjected to anoxia and reoxygenation. In comparison with control groups, hearts perfused in the presence of 5 mM fructose-1,6-bisphosphate throughout the different perfusion conditions showed higher concentrations of energy metabolites at the end of anoxia, most of which were normalized after reperfusion. Furthermore, in comparison with control hearts, a reduction of tissue malondialdehyde and of lactate dehydrogenase release in the perfusate was observed in fructose-1,6-bisphosphate-perfused hearts. In this article we review most of the available data concerning the ability of fructose-1,6-bisphosphate to protect from ischemia and reperfusion damage outlining those recent findings which contributed both to clarify the pharmacological profile of the drug and to give an insight in its probable mechanism of action.
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Affiliation(s)
- G Lazzarino
- Department of Experimental Medicine and Biochemical Sciences, II University of Rome, Tor Vergata, Italy
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25
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Nakai T, Tanimura H, Tabuse K, Nagai Y, Mori K, Yamoto H. Beneficial effects of fructose-1,6-diphosphate infusion on liver regeneration after ischemic liver injury. GASTROENTEROLOGIA JAPONICA 1991; 26:611-8. [PMID: 1752392 DOI: 10.1007/bf02781677] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effect of fructose-1,6-diphosphate (FDP) on cellular viability after partial hepatectomy in partial ischemic liver was investigated in rats. The administration of FDP did not increase blood flow in the hepatic tissue; however, it significantly suppressed the elevation of serum liver functions for 24 hours after partial hepatectomy. Levels of DNA synthesis, protein synthesis, and labeling index were significantly higher in the groups administered divided doses of FDP before and after partial hepatic ischemia than in the control group (P less than 0.01). Thus, these findings indicate that FDP has cytoprotective and hepatotrophic effects on liver with ischemic injury and that divided dose administration of FDP is more effective than bolus doses in decreasing damage following ischemic and reperfusion injury.
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Affiliation(s)
- T Nakai
- Department of Gastroenterological Surgery, Wakayama Medical College, Japan
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26
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Faroon OM, Henry RW, Soni MG, Mehendale HM. Potentiation of BrCCl3 hepatotoxicity by chlordecone: biochemical and ultrastructural study. Toxicol Appl Pharmacol 1991; 110:185-97. [PMID: 1716382 DOI: 10.1016/s0041-008x(05)80001-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Previous work has established that chlordecone (CD) potentiates the hepatotoxicity of BrCCl3. This interaction occurs at nontoxic levels of CD and BrCCl3. The present research was designed to investigate the mechanism governing the pathogenesis of potentiated hepatic injury and lethality induced by a low dose of BrCCl3 after dietary pretreatment with 10 ppm of CD for 15 days. On Day 16, a single dose of BrCCl3 (30 microliters/kg) was administered ip to rats maintained either on normal diet (ND) or on a diet contaminated with 10 ppm CD. Blood and liver samples were collected at 0, 3, 6, 12, 24, 36, and 48 hr after the halomethane administration for biochemical (ATP, bilirubin, glycogen) and for ultrastructural studies. A continuous increase in serum bilirubin and decrease in hepatic ATP and glycogen were observed in CD + BrCCl3 combination, indicating progressive injury, but not in other treatment groups. In ND + BrCCl3 combination, all biochemical indices were either normal or close to normal after 36 hr, suggesting complete recovery from hepatotoxicity. The most extensive ultrastructural changes characteristic of halomethane hepatotoxicity (necrosis, ballooned cells, and dilation of rough endoplasmic reticulum) were observed after the CD + BrCCl3 combination treatment. The progressive and early depletion of hepatic ATP and glycogen, and the progressive increase in toxicity along with decreased cell division in CD + BrCCl3-treated rats, indicate the association of compromised energy status and suppression of cell division and tissue repair in CD-potentiated BrCCl3 toxicity. These findings suggest that the suppression of stimulated hepatocellular regeneration results in the loss of the essential mechanism of tissue repair leading to continuation of the toxic liver injury associated with the CD + BrCCl3 combination treatment.
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Affiliation(s)
- O M Faroon
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson 39216-4505
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27
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Mehendale HM. Role of hepatocellular regeneration and hepatolobular healing in the final outcome of liver injury. A two-stage model of toxicity. Biochem Pharmacol 1991; 42:1155-62. [PMID: 1716097 DOI: 10.1016/0006-2952(91)90249-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- H M Mehendale
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson 39216-4505
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28
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Soni MG, Mehendale HM. Protection from chlordecone-amplified carbon tetrachloride toxicity by cyanidanol: biochemical and histological studies. Toxicol Appl Pharmacol 1991; 108:46-57. [PMID: 1706539 DOI: 10.1016/0041-008x(91)90267-i] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Chlordecone (CD) pretreatment is well known to greatly potentiate CCl4 toxicity. Previous work has shown that suppression of hepatocellular regeneration permits an ordinarily limited liver injury to progress in an irreversible manner. Insufficient hepatocellular energy has been proposed as a mechanism for suppressed hepatocellular regeneration. Since cyanidanol reportedly increases cellular ATP, this compound was employed to test the above hypothesis. The present study was designed to investigate the sequential biochemical and histological changes over a time course of 120 hr after CCl4 administration. Male Sprague-Dawley rats (125-150 g) were maintained on 10 ppm CD diet for 15 days and were challenged with either a standard protocol dose (100 microliters/kg) or a low (50 microliters/kg, L) dose of CCl4. Cyanidanol pretreatment at 48, 24, and 2 hr before CCl4 administration to rats maintained on CD diet resulted in 100 or 70% animal survival, for CCl4 (L) or the standard dose of CCl4, respectively. Preliminary studies indicated that neither simultaneous nor subsequent administration of cyanidanol with CCl4 challenge affords such protection. Prior treatment with cyanidanol and a latency period were found necessary for protection. Without cyanidanol, CD + CCl4 combination caused 50 and 100% lethality after CCl4 (L) and the standard dose, respectively, while the same doses of CCl4 alone did not cause lethal effects. Plasma enzymes (alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase) in control rats showed only moderate and transient increases after CCl4 challenge. The combination of CD + standard dose of CCl4 resulted in progressive and marked elevations of all three serum enzymes at all time intervals until the death of animals. Cyanidanol pretreatment resulted in significant decline in the plasma enzyme elevations at later time points. Cyanidanol pretreatment increased hepatic ATP synthesis in control or CD rats. CCl4 administration to control rats did not alter hepatic ATP levels, while in CD-fed rats hepatic ATP levels were significantly decreased. Cyanidanol pretreatment to CD + CCl4 combination-treated rats did not significantly prevent the decline in hepatic ATP and glycogen levels. However, in the surviving rats a recovery in these parameters was observed. Light microscopic examination of livers from animals that received CCl4 alone revealed only marginal cellular injury, at early time points only. However, CCl4 challenge to rats maintained on CD resulted in progressive injury, characterized by the appearance of ballooned cells, necrotic cells, and cells with lipid droplets in the liver. Cyanidanol pretreatment to these rats caused decreased vacuolation and significantly reduced the progression of liver necrosis.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- M G Soni
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson 39216-4505
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29
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Soni MG, Mehendale HM. Protection from chlordecone-amplified carbon tetrachloride toxicity by cyanidanol: regeneration studies. Toxicol Appl Pharmacol 1991; 108:58-66. [PMID: 1706540 DOI: 10.1016/0041-008x(91)90268-j] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Previous work has shown that chlordecone (CD)-amplified CCl4 hepatotoxicity and lethality can be mitigated by pretreatment with cyanidanol. These studies also revealed that stimulated hepatocellular regeneration might play an important role in the cyanidanol protection of CD-amplified CCl4 toxicity. The present studies conducted over a time course of 0 to 120 hr after CCl4 challenge describe sequential changes in hepatic [3H]thymidine incorporation into hepatocellular nuclear DNA, polyamines and related enzymes, and histomorphometry of liver sections from variously treated rats. Male Sprague-Dawley rats (125-150 g) were maintained on a control diet or on a diet contaminated with CD (10 ppm) for 15 days and/or pretreated with cyanidanol (250 mg/kg, ip) at 48, 24, and 2 hr before a single ip injection of either a standard protocol dose (100 microliters/kg) or a low dose (50 microliters/kg, L) of CCl4 on Day 16 of the dietary protocol. Cyanidanol pretreatment significantly stimulated the hepatic [3H]thymidine incorporation into hepatocellular nuclear DNA of control rats irrespective of CD pretreatment. Similarly, polyamine metabolism was altered favorably for cell division, although mitotic index (metaphase) was not increased. Cyanidanol-stimulated [3H]thymidine incorporation was highly suppressed in rats receiving the CD + CCl4 standard dose combination treatment up to 36 hr, but after this time point a marked increase was observed. Hepatocellular regeneration, quantified histomorphometrically as volume density of cells in metaphase, was progressively increased in rats protected from CD + CCl4 interaction by cyanidanol, starting at 36 hr and lasting until 72 hr. Favorably altered polyamine metabolism was evident from the stimulated ornithine decarboxylase, as well as from the stimulated interconversion of the higher polyamines to maintain increased concentration of putrescine. Challenge by the same dose of CCl4 (100 microliters/kg) to CD-pretreated rats not protected by cyanidanol failed to cause any increase in [3H]thymidine incorporation up to 36 hr and resulted in animal death starting at 36 hr. In the surviving rats, [3H]thymidine incorporation at 48 hr was increased, but was less than 50% of the increase observed in the cyanidanol group. In these rats, attenuation in the stimulation of cell division and insufficiently increased putrescine levels were observed, which are consistent with the inadequate level of hepatocellular regeneration. With rats receiving CD + CCl4(L) combination, the [3H]thymidine incorporation at 48 hr was less than 50% of the increase of cyanidanol-protected rats. Cyanidanol pretreatment to the CD + CCl4 group of rats prevented the decrease in the hepatic DNA levels.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- M G Soni
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson 39216-4505
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30
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Faroon OM, Mehendale HM. Bromotrichloromethane hepatotoxicity. The role of stimulated hepatocellular regeneration in recovery: biochemical and histopathological studies in control and chlordecone pretreated male rats. Toxicol Pathol 1990; 18:667-77. [PMID: 1709515 DOI: 10.1177/019262339001800426] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
It has been shown that BrCCl3 is a more potent hepatotoxin than CCl4. Pretreatment with nontoxic dietary levels of chlordecone (CD) results in amplification of BrCCl3 hepatotoxicity. The objective of this research was to investigate and compare the histopathological alterations during a time course after a low dose of BrCCl3 alone and in combination with dietary CD. Male Sprague-Dawley rats were maintained on 10 ppm dietary CD or normal diet for 15 days. On day 16, they received a single ip dose (30 microliters/kg) of BrCCl3 in corn oil (CO) vehicle or corn oil alone. Blood and liver samples were collected at 0, 3, 6, 12, 24, 36, 48, 72, 96, and 120 hr for serum enzymes and histopathological examination, respectively. Serum enzymes (SDH, ALT, AST) were significantly (p less than 0.05) elevated in rats receiving the CD + BrCCl3 combination in comparison to BrCCl3 alone. For 48 hr, a continuous increase in serum enzyme activities was detected in rats treated with CD + BrCCl3 combination, but not in the rats receiving other treatments (ND + BrCCl3, ND + CO, or CD + CO). The most extensive hepatolobular necrosis was observed in rats treated with the CD + BrCCl3 combination. Thirty-six hr after the administration of BrCCl3 to rats maintained on normal diet, high mitotic activity was observed, which continued through 72 hr resulting in complete restoration of hepatolobular structure. In contrast, rats receiving the combination of CD + BrCCl3 exhibited minimal and belated hepatomitotic activity for a short period of time, resulting in progressive hepatic failure, culminating in animal death. In conclusion, hepatotoxicity of a low dose of BrCCl3 alone appeared to be overcome via stimulated hepatocellular regeneration and hepatolobular restoration. CD appears to amplify BrCCl3 hepatotoxicity via interference with this hormetic mechanism, permitting a progressive and continued hepatic injury leading to complete hepatic failure, culminating in animal death.
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Affiliation(s)
- O M Faroon
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson 39216-4505
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Abstract
There is significant interest in the possibility of unusual toxicity due to interaction of toxic chemicals upon environmental or occupational exposures even though such exposures may involve levels ordinarily considered harmless individually. While many laboratory and experimental models exist for such interactions, progress in this area of toxicology has suffered for want of a model where the interactants are individually non-toxic. We developed such a model where prior exposure to non-toxic levels of the pesticide Kepone (chlordecone) results in a 67-fold amplification of CCl4 lethality in experimental animals. The mechanism(s) by which chlordecone amplifies the hepatotoxicity of halomethanes such as CCl4, CHCl3, and BrCCl3 has been a subject of intense study. The biological effects of this interaction include extensive hepatotoxicity characterized by histopathological alterations, hepatic dysfunction, and perturbation of related biochemical parameters. Close structural analogs of chlordecone such as mirex and photomirex do not share the propensity of chlordecone to potentiate halomethane toxicity. Mechanisms such as induction of microsomal cytochrome P-450 by chlordecone and greater lipid peroxidation are inadequate to explain the remarkably powerful potentiation of toxicity and lethality. Time-course studies in which liver tissue was examined 1-36 h after CCl4 administration were conducted. While animals receiving a normally nontoxic dose of CCl4 alone show limited hepatocellular necrosis by 6 h, proceeding to greater injury after 12 h, recovery phase ensues as revealed by greatly increased number of mitotic figures. Such regeneration and hepatic tissue repair processes are totally suppressed in animals exposed to chlordecone prior to CCl4. Thus, the arrested hepatocellular repair and renovation play a key role in the potentiation of CCl4 liver injury by chlordecone. These findings have allowed us to propose a novel hypothesis for the mechanism of chlordecone amplification of halomethane toxicity and lethality. While limited injury is initiated by the low dose of CCl4 by bioactivation followed by lipid peroxidation, this normally recoverable injury permissively progresses due to arrested hepatocellular regeneration and tissue repair processes. Recent studies designed to test this hypothesis have provided additional supporting evidence. Hepatocellular regeneration stimulated by partial hepatectomy was unaffected by 10 ppm dietary chlordecone, while these animals were protected from the hepatotoxic and lethal actions of CCl4 if administered at the time of maximal hepatocellular regeneration. The protection was abolished when CCl4 was administered upon cessation of hepatocellular regeneration.
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Affiliation(s)
- H M Mehendale
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson 39216
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