HEPATOTOXIC AND NEPHROTOXIC EFFECTS OF SODIUM SELENITE IN RATS

Bogdan Gabriel Şlencu1, Carmen Solcan2, Liliana Avasilcăi1, Rodica Cuciureanu1

1 School of Pharmacy, “Grigore T. Popa” University of Medicine and Pharmacy Iași, Romania2 School of Veterinary Medicine, “Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Iași, Romania

INTRODUCTION AND OBJECTIVES

Selenium is an essential microelement. In high doses it is generally toxic, both for animals and humans (Reilly, 2006). Elemental selenium is considered to be almost biologically inert (Zhang et al, 2005), due to insolubility. Inorganic salts, such as selenite and selenate, are very toxic (National Toxicology Program, 1994). Organic compounds of selenium, such as selenomethionine, are less toxic than the inorganic ones (Reilly, 2006; Schrauzer, 2000). Selenite can react intracellulary or extracellularly with glutathione (Mezes et Balogh, 2009). The objective of this study was to investigate and compare the subacute toxicity of sodium selenite administered by oral route at two different doses, in male rats.

MATERIAL AND METHOD

Male Wistar rats were used, which were randomly divided in one of the three experimental groups consisting in 5 rats each: Control, Se1 (1 mg Se+4 equivalent/kg body weight) and Se3 (3 mg Se+4 equivalent/kg body weight). All treatments were administered once a day for 10 consecutive days and the animals were sacrificed on the 11th day. The following biochemical parameters were determined from serum: alanine transaminase (ALT), aspartate transaminase (AST), serum iron, total bilirubin, direct bilirubin, gamma glutamyl transpeptidase (GGT), total cholesterol, HDL-cholesterol, LDL-cholesterol, serum urea, serum creatinine, serum uric acid. A full blood count was performed. Liver and kidney sections were stained with hematoxylin and eosin (HE technique) and analyzed.

RESULTS

Selenite interfered with the growth gain and caused an increase in ALT, AST and GGT activities and in the levels of total and direct bilirubin, serum iron, total cholesterol, HDL-cholesterol and LDL-cholesterol (Table I). Selenite caused a decrease in WBC and RBC numbers and in HGB concentration (Table II). In the two selenite groups hydropic degeneration, perivascular edema, cells with apoptotic bodies, intensely acidophilic cells with picnotic nuclei, oval cells, necrosis and anuclear cells were observed in the livers (Table III, Table IV). Hydropic degeneration, intensely acidophilic cells with picnotic nuclei, hyaline cylinders, congestion, vascular ectasia and perivascular edema were observed in the kidneys.

REFERENCES Mezes M, Balogh K. Prooxidant mechanisms of selenium toxicity - a review. Acta Biologica Szegediensis 2009; 53:15-18. National Toxicology Program. NTP technical report on toxicity studies of sodium selenate and sodium selenite administered in drinking water to F344/N rats and B6C3F1 mice, In: Toxicity Report Series No. 38. NIH Publication 94-3387, Bethesda, Maryland: National Institutes of Health, 1994. Reilly C. Selenium in food and health, 2nd edition. New York: Springer, 2006. Schrauzer GN. Selenomethionine: a review of its nutritional significance, metabolism and toxicity. J Nutr 2000; 130:1653-1656. Zhang J, Wang H, Yan X, Zhang L. Comparison of short-term toxicity between Nano-Se and selenite in mice. Life Sci 2005; 76: 1099-1109.

CONCLUSIONS

These data indicate a dose-dependent effect of sodium selenite on pathological changes in biochemical parameters and in histological architecture. Oval cells were significantly present only in the livers of the rats receiving the highest dose of selenite (3 mg Se+4/kg body weight). At the lowest dose it could be possible that the induced hepatic histopathological changes could be reversible.

Biochemical parameters Control Se1 Se3ALT (IU/l) 46,60±4,47 119,50±34,29 181,66±44,75AST (IU/l) 125,60±7,69 213,00±38,98 265,00±33,70Serum iron (μg/dl) 232,75±8,02 303,00±19,65* 290,40±46,18*Total bilirubin (mg/dl) 0,16±0,01 0,18±0,02 0,42±0,08Direct bilirubin (mg/dl) 0,01±0,00 0,05±0,00* 0,16±0,04GGT (IU/l) 1,00±0,00 1,00±0,00 4,75±1,03*Total cholesterol (mg/dl) 61,80±3,13 65,25±5,76 76,75±5,34HDL-cholesterol (mg/dl) 19,40±0,87 28,20±4,29 24,50±1,55*LDL-cholesterol (mg/dl) 4,20±0,37 6,40±1,28 6,50±0,86Serum urea (mg/dl) 38,00±4,03 41,25±0,94 37,20±0,96Serum creatinine (mg/dl) 0,61±0,01 0,61±0,00 0,56±0,01*Serum uric acid (mg/dl) 0,97±0,05 1,12±0,10 1,05±0,08

Results are mean ± SEM of 5 animals in each group; * - significantly different compared to control (p < 0,05)

Table I. Effect of sodium selenite on some biochemical parameters

Rat no.

Areas of necrosis

Oval cells in the portal spacesb

(no.)

Intralobular oval cellsb

(no. of groups)

Perivascular oedema and

vascular ectasia

Hydropic degeneration

1 + 80 6/8 +++ ++++2 ++ 79 4/6 +++ ++++3 ++ 89 3/5 ++++ ++++4 + 87 6/9 +++ ++++5 +++ 91 4/7 ++++ ++++

+ = low intensity and/or occurrence; ++ = moderate intensity and/or occurrence; +++ = high intensity and/or occurrence; ++++ = very high intensity and/or occurrence;b - a number of 10 microscopic fields of view were analyzed, in which the cells/elements of interest were counted;

Table IV. Hepatic lesions in the Se3 group

Rat no.

Anuclear cellsa

(no./100 cells)

Intensely acidophilic cells with picnotic

nucleia

(no./100 cells)

Cells with apoptotic

bodiesa

(no.)

Perivascular edema

Hydropic degeneration

1 28,7 3 4 + +2 27,6 13 4 + ++3 31,3 9 1 + ++4 29,5 6 3 + +5 30,1 11 2 + ++

+ = low intensity and/or occurrence; ++ = moderate intensity and/or occurrence; +++ = high intensity and/or occurrence; ++++ = very high intensity and/or occurrence; a – a number of 10 microscopic fields of view were analyzed, in which the modified cells/elements of interest were counted and reported to the total number of cells observed in these areas;

Table III. Hepatic lesions in the Se1 group

Haematological parameters Control Se1 Se3White blood count (WBC) ; (No./μl) 4341±334 2756±312* 3591±669

Red blood count (RBC) ; (No./μl) 8440±271 8136±219 7125±301*Haemoglobin (HGB) ; (g/dl) 15,52±0,28 14,62±0,25* 13,14±0,40*

Hematocrit (HCT) ; (%) 44,80±0,74 44,3±0,66 39,82±0,99*Mean corpuscular haemoglobin

(MCH) ; (pg)18,34±0,25 18,00±0,30 18,50±0,29

Mean corp. haemoglobin conc. (MCHC) ; (g/dl)

34,64±0,38 32,98±0,33* 32,98±0,19*

Results are mean ± SEM of 5 animals in each group; * - significantly different compared to control (p < 0,05)

Table II. Effect of sodium selenite on some haematological parameters