Abstract
A firm knowledge of the normal structure is crucial for evaluating pathological processes and morphofunctional correlations. Stereological liver structure characterization had its debut for mammals in the 1960s, but only in the 1980s did it start to be used in fishes. Using stereology, our aim was to verify the hypothesis that in parallel with the well-known annual seasonal changes in the liver–body ratio of brown trout, hepatocytes would vary their number and/or size, and that gender differences likely exist. Three-year-old specimens were used. Five animals per gender were examined in May (endogenous vitellogenesis), September (exogenous vitellogenesis), and February (spawning season end). The liver was fixed by perfusion, and its total volume estimated. Systematically sampled material was embedded in epoxy or in metachrylate resins. Stereology was executed on light and electron microscopy images. Unbiased design-based techniques were applied, using physical disectors and differential point counting. Target parameters were the relative (per unit volume) and total number of hepatocytes, the mean cell and nuclear volumes, and the total volumes of hepatocytes and their nuclei. Data support that in both genders the number of hepatocytes and the volume of its nucleus change along the breeding cycle. The cell number increased from endogenous to exogenous vitellogenesis (accompanying relative liver size gains), later followed by a decline in the cell number, still detectable after the spawning season. The total liver volumes of the cell and nucleus also increased from May to September in females, despite that the mean hepatocyte nuclear volume showed a minimum in September. No statistical changes in the mean cell volume were detected, regardless of the tendency for lower mean values in September. Changes were more marked in females and showed a higher correlation with the gonad weight. It was firstly suggested that numerical (rather than cell size) changes govern the shifts of the relative liver weight seen during the brown trout annual breeding cycle, and eventually of other fishes. We hypothesized that there are seasonal cycles of hepatocyte mitosis (from after spawning to exogenous vitellogenesis) and of apoptosis (at spawning). These cycles would be regulated by sex steroids, being more striking in females.
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References
Bailey GS, Williams DE, Hendricks JD (1996) Fish models for environmental carcinogenesis: the rainbow trout. Environ Health Perspect 104:5–21
Beresford WA, Henninger JM (1986) A tabular comparative histology of the liver. Arch Histol Jpn 49:267–281
Caballero MJ, López-Calero G, Socorro J, Roo FJ, Izquierdo MS, Férnandez AJ (1999) Combined effect of lipid level and fish meal quality on liver histology of gilthead seabream (Sparus aurata). Aquaculture 179:277–290
Coggeshall RE, Lekan HA (1996) Methods for determining numbers of cells and synapses: a case for more uniform standards of review. J Comp Neurol 364:6–15
Copeland PA, Sumpter JP, Walker TK, Croft M (1986) Vitellogenin levels in male and female rainbow trout (Salmo gairdneri Richardson) at various stages of the reproductive cycle. Comp Biochem Physiol 83B:487–493
Elias H, Bengelsdorf H (1952) The structure of the liver of vertebrates. Acta Anat 14:24–337
Figueiredo-Fernandes A, Fontaínhas-Fernandes A, Monteiro RAF, Reis-Henriques MA, Rocha E (2006) Effects of the fungicide mancozeb in the liver structure of Nile Tilapia, Oreochromis niloticus—assessment and quantification of induced cytological changes using qualitative histopathology and the stereological point-sampled intercept method. Bull Environ Contam Toxicol 76:249–255
Figueiredo-Silva A, Rocha E, Dias J, Silva P, Rema P, Gomes E, Valente LMP (2005) Partial replacement of fish oil by soybean oil on lipid distribution and liver histology in European sea bass (Dicentrarchus labrax) and rainbow trout (Oncorhynchus mykiss) juveniles. Aquacult Nutr 11:147–155
Gerrits PO, Hrobin RW, Stokroos I (1991) The effects of glycol metachrylate as a dehydrating agent on the dimensional changes of liver tissue. J Microsc 165:273–280
Gundersen HJG (1977) Notes on the estimation of the numerical density of arbitrary profiles: the edge effect. J Microsc 111:219–223
Gundersen HJG (1986) Stereology of arbitrary particles. A review of unbiased number and size estimators and the presentation of some new ones, in memory of William R. Thompson. J Microsc 143:3–45
Hampton JA, Lantz RC, Hinton DE (1989) Functional units in rainbow trout (Salmo gairdneri, Richardson) liver: III. Morphometric analysis of parenchyma, stroma, and component cell types. Am J Anat 185:58–73
Hanstede JG, Gerrits PO (1983) The effects of embedding in water-soluble plastics on the final dimensions of liver. J Microsc 131:79–86
Hardman RC, Volz DC, Kullman SW, Hinton DE (2007) An in vivo look at vertebrate liver architecture: three-dimensional reconstructions from medaka (Oryzias latipes). Anat Rec 290:770–782
Hinton DE, Couch JA (1998) Architectural pattern, tissue and cellular morphology in liver of fishes: relationship to experimentally-induced neoplastic responses. In: Braunbeck T, Hinton DE, Streit B (eds) Fish ecotoxicology. Birkhäuser, Basel, pp 141–164
Hinton DE, Laurén DJ (1990) Liver structural alterations accompanying chronic toxicity in fishes: Potential biomarkers of exposure. In: McCarthy JF, Shugart LR (eds) Biomarkers of environmental contamination. Lewis Publishers, Boca Raton, pp 17–57
Hinton DE, Lantz RC, Hampton JA (1984) Effect of age and exposure to a carcinogen on the structure of the medaka liver: a morphometric study. Natl Cancer Inst Monogr 65:239–249
Howard CV, Reed MG (1998) Unbiased stereology. Three-dimensional measurement in microscopy. Microscopy Handbook Series 41. Bios Scientific Publishers, Oxford
Ikeda K, Kinoshita H, Hirohashi K, Kubo S, Kaneda K (1995) The ultrastructure, kinetics and intralobular distribution of apoptotic hepatocytes after portal branch ligation with special reference to their relationship to necrotic hepatocytes. Arch Histol Cytol 58:171–184
Ishii K, Yamamoto K (1970) Sexual differences of the liver cells in the goldfish, Carassius auratus L. Bull Fac Fish Hokkaido Univ 21:271–110
Jack EM, Bentley P, Bieri F, Muakkassah-Kelly SF, Stäubli W, Suter J, Waechter F, Cruz-Orive LM (1990a) Increase in hepatocyte and nuclear volume and decrease in the population of binucleated cells in preneoplastic foci of rat liver: a stereological study using the nucleator method. Hepatology 11:286–297
Jack EM, Stäubli W, Waechter F, Bentley P, Suter J, Bieri F, Muakkassah-Kelly SF, Cruz-Orive LM (1990b) Ultrastructural changes in chemically induced preneoplastic focal lesions in the rat liver: a stereological study. Carcinogenesis 11:1531–1538
Jones AL, Spring-Mills E (1988) The liver and gallbladder. In: Weiss L (ed) Cell and tissue biology—a textbook of histology. Urban & Schwarzenberg, Munich, pp 687–714
Jordanova M (2004) The liver in female Salmo letnica Kar. (Teleostei, Salmonidae) during the reproductive cycle: a microscopic study of the natural population of Lake Ohrid. Doctoral Thesis. University of St. Kiril and Metodij, Faculty of Natural Sciences and Mathematics, Institute of Biology. Skopje, FYR Macedonia
Loud AV (1968) A quantitative stereological description of the ultrastructure of normal rat liver parenchymal cells. J Cell Biol 37:27–46
Marcos R, Rocha E, Henrique RMF, Monteiro RAF (2003) A new approach to an unbiased estimate of the hepatic stellate cell index in the rat liver—an example in healthy conditions. J Histochem Cytochem 51:1101–1104
Marcos R, Monteiro RAF, Rocha E (2004) Estimation of the number of stellate cells in a liver with the smooth fractionator. J Microsc 215:174–182
Marcos R, Monteiro RAF, Rocha E (2006) Design-based estimation of hepatocyte number, by combining the smooth fractionator and immunocytochemistry with policlonal antibodies for carcinoembryonic antigen. Liver Int 26:116–124
Majno G, Joris I (1995) Apoptosis, oncosis, and necrosis. An overview of cell death. Am J Pathol 146:3–15
Moutou KA, Braunbeck T, Houlihan DF (1997) Quantitative analysis of alterations in liver ultrastructure of rainbow trout Oncorhynchus mykiss after administration of the aquaculture antibacterials oxolinic acid and flumequine. Dis Aquat Org 29:21–34
Ng TB, Idler DR (1983) Yolk formation and differentiation in teleost fishes. In: Hoar WS, Randall DJ, Donaldson EM (eds) Fish physiology, vol IXA. Academic Press, New York, pp 373–404
Nigrelli RF, Jakowska S (1961) Fatty degeneration, regenerative hyperplasia and neoplasia in the livers of rainbow trout, Salmo gairdneri. Zoologica 46:49–61
Peute J, Huiskamp R, van Oordt PGWJ (1985) Quantitative analysis of estradiol–17β-induced changes in the ultrastructure of the liver of the male zebrafish, Brachidanio rerio. Cell Tissue Res 242:377–382
Rocha E, Monteiro RAF (1999) Histology and cytology of fish liver: a review. In: Saksena DN (ed) Ichthyology: Recent research advances. Science Publishers Inc, Enfield, pp 321–344
Rocha E, Monteiro RAF, Pereira CA (1994a) The liver of the brown trout, Salmo trutta fario: a light and electron microscope study. J Anat 185:241–249
Rocha E, Monteiro RAF, Pereira CA (1994b) Presence of rodlet cells in the intrahepatic biliary ducts of the brown trout, Salmo trutta fario Linnaeus, 1758 (Teleostei, Salmonidae). Can J Zool 72:1683–1687
Rocha E, Monteiro RAF, Pereira CA (1995) Microanatomical organization of hepatic stroma of the brown trout, Salmo trutta fario (Teleostei, Salmonidae): a qualitative and quantitative approach. J Morphol 223:1–11
Rocha E, Monteiro RAF, Pereira CA (1996) The pale-grey interhepatocytic cells of brown trout (Salmo trutta) are a subpopulation of macrophages or do they establish a different cellular type? J Submicrosc Cytol Pathol 28:357–368
Rocha E, Monteiro RAF, Pereira CA (1997) Liver of the brown trout, Salmo trutta (Teleostei, Salmonidae): a stereological study at light and electron microscopic levels. Anat Rec 247:317–328
Rocha E, Lobo-da-Cunha A, Monteiro RAF, Silva MW, Oliveira MH (1999) A stereological study along the year on the hepatocytic peroxisomes of brown trout (Salmo trutta). J Submicrosc Cytol Pathol 31:91–105
Rocha E, Monteiro RAF, Silva MW, Oliveira MH (2001) The hepatocytes of the brown trout (Salmo trutta f. fario): a quantitative study using design-based stereology. Histol Histopathol 16:423–437
Saper CB (1996) Any way you cut it: a new journal policy for the use of unbiased counting methods. J Comp Neurol 364:5
Scherle W (1970) A simple method for volumetry of organs in quantitative stereology. Mikroskopie 26:57–60
Selman K, Wallace RA, Barr V (1987) The relationship of yolk vesicles and cortical alveoli in teleost oocytes and eggs. In: Idler DR, Crim LW, Walsh JM (eds) Reproductive physiology of fish. Newfoundland Memorial University, St. Johns, pp 216
Schramm M, Muller E, Triebskorn R (1998) Brown trout (Salmo trutta f. fario) liver ultrastructure as a biomarker for assessment of small stream pollution. Biomarkers 3:93–108
Srivastava SJ, Saxena AK (1996) Morphological changes in hepatocytes in relation to reproductive cycle of a freshwater female catfish, Heteropneustes fossilis (Bloch). J Adv Zool 17:98–104
Sterio DC (1984) The unbiased estimation of number and sizes of arbitrary particles using the disector. J Microsc 134:127–136
Takahashi K, Sugawara Y, Sato R (1977) Fine structure of the liver cells in maturing and spawning female chum salmon, Oncorhynchus keta (Walbaum). Tohoku J Agricult Res 28:103–110
van Bohemen ChG, Lambert JGD, Peute J (1981) Annual changes in plasma and liver in relation to vitellogenesis in the female rainbow trout, Salmo gairdneri. Gen Comp Endocrinol 44:94–107
Washburn BS, Frye DJ, Hung SSO, Doroshov SI, Conte FS (1990) Dietary effects on tissue composition, oogenesis and the reproductive performance of female rainbow trout (Oncorhynchus mykiss). Aquaculture 90:179–195
Watanabe T, Tanaka Y (1982) Age-related alterations in size of human hepatocytes: a study of mononuclear and binucleate cells. Virchows Arch B 39:9–20
Weibel ER (1979) Stereological methods. Practical methods for biological morphometry, vol I. Academic Press, London
Weibel ER, Stäubli W, Gnägi HR, Hess FA (1969) Correlated morphometric and biochemical studies on the liver cell. J Cell Biol 42:68–91
Yadetie F, Arukwe A, Goksøyr A, Male R (1999) Induction of hepatic estrogen receptor in juveline Atlantic salmon in vivo by the environmental estrogen, 4-nonylphenol. Sci Total Environ 233:201–210
Acknowledgments
The fish were provided by the Direcção Regional de Agricultura de Entre-Douro e Minho under a cooperation protocol for science development; in this regard, the commitment of Eng. A. Gonçalves, Eng. A. Maia, Eng. C. Pereira, and others is greatly appreciated. This study was financially supported by the Fundação para a Ciência e Tecnologia, FCT (Lisbon, Portugal). The present study was undertaken in compliance with the national laws governing the use of animals in scientific studies.
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Rocha, E., Rocha, M.J., Galante, M.H. et al. The hepatocytes of the brown trout (Salmo trutta f. fario): a stereological study of their number and size during the breeding cycle. Ichthyol Res 56, 43–54 (2009). https://doi.org/10.1007/s10228-008-0066-x
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DOI: https://doi.org/10.1007/s10228-008-0066-x