EJMS

Abstract

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,4,7,8 Pentachloro-dibenzofuran (PeCDF) are widely distributed and persistent organic pollutants (POPs) in the environment with hazardous side effects on the tissues especially the liver. This study aimed to clarify their toxic effect on the histological and immunohistochemical structure of the liver of adult male albino rats and the possibility of improvement after cessation of their administration. Also, to evaluate the possible protective effect of green tea administration. Forty-eight adult male albino rats were classified into four groups; control group (I), dioxins treated group (II): received a mixture of TCDD at 100ng/kg/day and PeCDF at 200 ng/kg/day (in corn oil: acetone 99:1) five days a week for 13 weeks. Recovery group (III): the animals were given dioxin and furan in the same dose and duration as in group (II) then they were sacrificed four weeks after cessation of treatment. Group (IV): the animals received in the same doses of dioxin and furan followed by green tea extract at a dose of 40 mg/kg/day for the same duration as in group (II). Samples from the liver were stained with H&E, PAS and immunohistochemical detection of aryl hydrocarbon receptors (AhR). Morphometrical and statistical analysis were also done. Examinations of dioxins treated group revealed loss of lobular architecture. Also, marked cytoplasmic vacuolations were evident. Congested dilated blood sinusoids and bile duct proliferations with cellular infiltrations were clearly observed. These changes were associated with increased immunohistochemical expression of AhR. Some of these changes persisted after stoppage of TCDD and PeCDF administration. On the other hand, green tea supplementation showed a protective effect against TCDD and PeCDF induced hepatotoxicity with restoration of many hepatic lobules. Although, hepatocytes were mostly similar to control group; yet sinusoidal wall remained dilated. These results suggested that TCDD and PeCDF have potent hepatotoxic effects which could be ameliorated to a great extent with simultaneous supplementation with green tea.