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Protective effects of sulforaphane on acetaminophen-induced hepatotoxicity in mice
S238
Abstracts / Toxicology Letters 221S (2013) S59–S256
P23-15 Protective effects of sulforaphane on acetaminophen-induced hepatotoxicity in mice Yasuhiro Masubuchi ∗ , Ayano Shiiki, Astushi Matsumura, Masahiro Makita Chiba Institute of Science, Choshi, Japan Purpose: Sulforaphane (SFN) is a natural dietary isothiocyanate contained in broccoli, which has been proposed as a hepatoprotective compound. SFN activates nuclear factor E2-related factor 2 (Nrf2), possibly providing its hepatoprotective effect against xenobiotics. Here, we examined the effects of SFN on acetaminophen (APAP) hepatotoxicity, which could be suppressed by Nrf2regulated enzymes such as glutamate-cysteine ligase (GCL), a rate-limiting enzyme in glutathione (GSH) synthesis. Methods: Male CD-1 mice were given SFN intraperitoneally 16 or 1 h prior to APAP administration. Hepatotoxicity was assessed by histoochemistry and serum leakage of alanine aminotransferase. GSH levels were determined by the dithionitrobenzoic acid-glutathione disulfide reductase recycling assay. GCL catalytic subunit (GCLC) mRNA expression was assayed by real-time RT-PCR. Results and discussion: Pretreatment of mice with early SFN treatment (16 hr before APAP) resulted in protection against APAP hepatotoxicity, but late SFN treatment (1 hr before APAP) did not provide the hepatoprotection. Hepatic GSH depleted rapidly after APAP administration in the both SFN-treated groups and untreated mice, whereas its recovery was more pronounced in the mice with early SFN treatment. Treatment of mice with SFN alone resulted in a temporary decrease in GSH levels. APAP administration as well as SFN induced hepatic GCLC, whereas early or late SFN treatment did not cause an additional GCLC induction in APAP-treated mice. These results suggest that the SFN-induced rapid recovery of hepatic GSH is involved in the protection against APAP hepatotoxicity, while Nrf2-regulated transcripts other than GCLC should also contribute to the rapid GSH recovery. http://dx.doi.org/10.1016/j.toxlet.2013.05.583
P23-16 TCDD-induced sebaceous gland atrophy in mice: Kinetics of restoration following end of treatment Fabienne Fontao ∗ , Frédérique Ino, Olivier Sorg, Jean-Hilaire Saurat Swiss Centre for Applied Human Toxicology, University of Geneva, Switzerland 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was shown to induce the atrophy of sebaceous glands and the development of cutaneous hamartomas in a man suffering from TCDD intoxication (Toxicol. Sci. 125, 310–317, 2012). To analyse this process and a possible restoration of normal skin, TCDD (0.2 g/ml) was applied on the back of SKH-1 hairless mice 3 times per week for 4 weeks. The density of sebaceous glands decreased to 6% of vehicle-treated mice, but no hamartoma was observed. TCDD penetrated through the skin and reached the bloodstream, leading to a 55% decrease of liver vitamin A. A longer treatment was not possible due to liver toxicity. To decrease the systemic toxicity, we applied TCDD at 0.5 g/ml for 5 weeks on C57BL/6 mouse ears to analyse the sebaceaous glands. The density of sebaceous glands and differentiated sebocytes decreased to 18% and 35% of vehicle-treated
mice, respectively, whereas the average size of sebaceous glands decreased to 60% of vehicle-treated mice. Eight weeks following the end of TCDD application, the density of sebaceous glands and differentiated sebocytes reached 53% and 88% of vehicle-treated mice, whereas the average size of sebaceous glands returned to the size of vehicle-treated mice. These data lead to the following conclusions: (i) the atrophy of sebaceous glands and their replacement by skin hamartomas, at least in our mouse model, are distinct processes; (ii) the atrophy of sebaceous glands is reversible; however, in humans, due to the long half-life of TCDD (7–10 years), this restoration is expected to take several years. http://dx.doi.org/10.1016/j.toxlet.2013.05.584
P23-17 Study of benzophenone induced oxidative stress in the cytomorphological alterations of rat lung Uma Dutta P.G. Dept. of Zoology, Cotton College State University, Pan Bazar, Guwahati, Assam 781001, India Application of sunscreens during daylight hours has been well accepted due to awareness of health threats from skin cancer induced by sunlight. Benzophenone (BZ) is used as a primary ingredient in commercial sunscreen formulations. Thus consumers are exposed to this chemical daily through its cosmetic products. On metabolic biotransformation, BZ generates ROS that leads to oxidative stress (OS) condition. The present study was designed to evaluate the possible OS effect on the lungs of albino rat chronically exposed to BZ at sublethal dose (15 mg/ml/kg body wt./day) for 17 weeks. The assessment was based on cytomorphological alterations at cellular and subcellular levels following routine techniques. The striking histopathological changes manifested in the lungs were emphysema, extensive hemorrhages with heart failure cells and peribronchial lymphoidal hyperplasia. Presence of bronchogenic carcinoma in some larger bronchioles was characterized by proliferated hyperchromic neoplastic cells forming a solid sheet. SEM studies revealed oxidative damage in the alveolar cytomembrane characterized by perforated lesions in swollen and thickened aleveolar septa. Undifferentiated cubodial pneumocytic cells with elongated microvilli, and pulmonary macrophages with extensive membrane ruffles indicated hyperplastic effect of the chemical. Ultramicroscopical changes showed mitochondrial swelling with partial cristiolysis and disrupted membrane. Whorls formation by extensive dilated smooth ER around a degenerated mitochondrion and preponderance of rough ER suggested that the chemical exerted OS in the organelle. The study concluded that BZ is a potent agent of OS causing damage in the cytomembrane of pneumocytic cell, which may in the long run bring about irreversible respiratory disorder. http://dx.doi.org/10.1016/j.toxlet.2013.05.654
Abstracts / Toxicology Letters 221S (2013) S59–S256
P23-15 Protective effects of sulforaphane on acetaminophen-induced hepatotoxicity in mice Yasuhiro Masubuchi ∗ , Ayano Shiiki, Astushi Matsumura, Masahiro Makita Chiba Institute of Science, Choshi, Japan Purpose: Sulforaphane (SFN) is a natural dietary isothiocyanate contained in broccoli, which has been proposed as a hepatoprotective compound. SFN activates nuclear factor E2-related factor 2 (Nrf2), possibly providing its hepatoprotective effect against xenobiotics. Here, we examined the effects of SFN on acetaminophen (APAP) hepatotoxicity, which could be suppressed by Nrf2regulated enzymes such as glutamate-cysteine ligase (GCL), a rate-limiting enzyme in glutathione (GSH) synthesis. Methods: Male CD-1 mice were given SFN intraperitoneally 16 or 1 h prior to APAP administration. Hepatotoxicity was assessed by histoochemistry and serum leakage of alanine aminotransferase. GSH levels were determined by the dithionitrobenzoic acid-glutathione disulfide reductase recycling assay. GCL catalytic subunit (GCLC) mRNA expression was assayed by real-time RT-PCR. Results and discussion: Pretreatment of mice with early SFN treatment (16 hr before APAP) resulted in protection against APAP hepatotoxicity, but late SFN treatment (1 hr before APAP) did not provide the hepatoprotection. Hepatic GSH depleted rapidly after APAP administration in the both SFN-treated groups and untreated mice, whereas its recovery was more pronounced in the mice with early SFN treatment. Treatment of mice with SFN alone resulted in a temporary decrease in GSH levels. APAP administration as well as SFN induced hepatic GCLC, whereas early or late SFN treatment did not cause an additional GCLC induction in APAP-treated mice. These results suggest that the SFN-induced rapid recovery of hepatic GSH is involved in the protection against APAP hepatotoxicity, while Nrf2-regulated transcripts other than GCLC should also contribute to the rapid GSH recovery. http://dx.doi.org/10.1016/j.toxlet.2013.05.583
P23-16 TCDD-induced sebaceous gland atrophy in mice: Kinetics of restoration following end of treatment Fabienne Fontao ∗ , Frédérique Ino, Olivier Sorg, Jean-Hilaire Saurat Swiss Centre for Applied Human Toxicology, University of Geneva, Switzerland 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was shown to induce the atrophy of sebaceous glands and the development of cutaneous hamartomas in a man suffering from TCDD intoxication (Toxicol. Sci. 125, 310–317, 2012). To analyse this process and a possible restoration of normal skin, TCDD (0.2 g/ml) was applied on the back of SKH-1 hairless mice 3 times per week for 4 weeks. The density of sebaceous glands decreased to 6% of vehicle-treated mice, but no hamartoma was observed. TCDD penetrated through the skin and reached the bloodstream, leading to a 55% decrease of liver vitamin A. A longer treatment was not possible due to liver toxicity. To decrease the systemic toxicity, we applied TCDD at 0.5 g/ml for 5 weeks on C57BL/6 mouse ears to analyse the sebaceaous glands. The density of sebaceous glands and differentiated sebocytes decreased to 18% and 35% of vehicle-treated
mice, respectively, whereas the average size of sebaceous glands decreased to 60% of vehicle-treated mice. Eight weeks following the end of TCDD application, the density of sebaceous glands and differentiated sebocytes reached 53% and 88% of vehicle-treated mice, whereas the average size of sebaceous glands returned to the size of vehicle-treated mice. These data lead to the following conclusions: (i) the atrophy of sebaceous glands and their replacement by skin hamartomas, at least in our mouse model, are distinct processes; (ii) the atrophy of sebaceous glands is reversible; however, in humans, due to the long half-life of TCDD (7–10 years), this restoration is expected to take several years. http://dx.doi.org/10.1016/j.toxlet.2013.05.584
P23-17 Study of benzophenone induced oxidative stress in the cytomorphological alterations of rat lung Uma Dutta P.G. Dept. of Zoology, Cotton College State University, Pan Bazar, Guwahati, Assam 781001, India Application of sunscreens during daylight hours has been well accepted due to awareness of health threats from skin cancer induced by sunlight. Benzophenone (BZ) is used as a primary ingredient in commercial sunscreen formulations. Thus consumers are exposed to this chemical daily through its cosmetic products. On metabolic biotransformation, BZ generates ROS that leads to oxidative stress (OS) condition. The present study was designed to evaluate the possible OS effect on the lungs of albino rat chronically exposed to BZ at sublethal dose (15 mg/ml/kg body wt./day) for 17 weeks. The assessment was based on cytomorphological alterations at cellular and subcellular levels following routine techniques. The striking histopathological changes manifested in the lungs were emphysema, extensive hemorrhages with heart failure cells and peribronchial lymphoidal hyperplasia. Presence of bronchogenic carcinoma in some larger bronchioles was characterized by proliferated hyperchromic neoplastic cells forming a solid sheet. SEM studies revealed oxidative damage in the alveolar cytomembrane characterized by perforated lesions in swollen and thickened aleveolar septa. Undifferentiated cubodial pneumocytic cells with elongated microvilli, and pulmonary macrophages with extensive membrane ruffles indicated hyperplastic effect of the chemical. Ultramicroscopical changes showed mitochondrial swelling with partial cristiolysis and disrupted membrane. Whorls formation by extensive dilated smooth ER around a degenerated mitochondrion and preponderance of rough ER suggested that the chemical exerted OS in the organelle. The study concluded that BZ is a potent agent of OS causing damage in the cytomembrane of pneumocytic cell, which may in the long run bring about irreversible respiratory disorder. http://dx.doi.org/10.1016/j.toxlet.2013.05.654