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Neuroprotective effect of magnolol in the hippocampus of senescence-accelerated mice (SAMP1)
International Congress Series 1260 (2004) 405 – 408
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Neuroprotective effect of magnolol in the hippocampus of senescence-accelerated mice (SAMP1) Masaaki Akagi a,*, Toshimasa Tada a, Akiko Shirono a, Yoshiyasu Fukuyama a, Kousuke Nakade a, Haifeng Zhai a, Yumiko Yasui a, Reiko Akagi b a
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihama-bouji, Yamashiro-cho, Tokushima 770-8514, Japan b Faculty of Health and Welfare Science, Okayama Prefectural University, Kuboki, Souzya 719-1197, Japan Received 19 June 2003; received in revised form 19 June 2003; accepted 10 September 2003
Abstract. We investigated age-dependent neuronal loss in the hippocampus and the protective effect of magnolol using SAMP1 mice in comparison with SAMR1. SAMP1 and SAMR1, 2 to 10 months old, were used. Magnolol (2 and 5 mg/kg) was orally administered once a day for 7 days to 2-monthold mice and evaluation was carried out at 4 months. The density of neurofibrils and axons decreased with aging in the CA1 and CA3 regions of the hippocampus. The rate of decrease in SAMP1 was greater than that of SAMR1. Treatment with magnolol dose-dependently prevented the decrease of density in CA1 and CA3 at 4 months. However, until the age of 4 months, SAMP1 animals did not behaviorally differ from SAMR1 either with or without magnolol. It has been suggested that imbalance between the rates of generation and utilization of reactive oxygen species (ROS) and organic free radicals may be one of the main reasons for accelerated aging of SAMP1 animals. These findings suggest that the antioxidant and free radical scavenging activity of magnolol may contribute to the protective effect against neuronal loss in the hippocampus. D 2003 Elsevier B.V. All rights reserved. Keywords: Magnolol; Hippocampus; Senescence; SAMP1
1. Introduction Magnolol (5,5V-di-2-propenyl-1,1V-biphenyl-2,2V-diol), which was originally extracted from the Chinese medicinal herb Magnolia officinalis, in used as an anti-allergy and anti-asthma compound with a wide spectrum of pharmacological activities [1]. Magnolol possesses potent antioxidant and free radical scavenging activities [2]. It has also been reported to be 1000 times more potent than alpha-tocopherol in inhibiting * Corresponding author. Tel.: +81-88-622-9611; fax: +81-88-655-3051. E-mail address: [email protected] (M. Akagi). 0531-5131/ D 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0531-5131(03)01679-0
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M. Akagi et al. / International Congress Series 1260 (2004) 405–408
lipid peroxidation in rat heart mitochondria and 50 000 times more potent than glutathione in reversing the iron-induced reduction of beating frequency in the human sperm tail [3,4]. The SAMP1 mouse, separated from several SAMP strains, is characterized by senile amyloidosis and age-related decline in antibody-forming capacity [5,6]. In the present study, we investigated the age-dependent neuronal loss in the hippocampus and the protective effect of magnolol using SAMP1 in comparison with SAMR1. 2. Materials and methods All experiments were conducted in accordance with the Guiding Principles for the Care and Use of Laboratory Animals approved by The Japanese Pharmacological Society. The substrains of SAM, SAMP1 and SAMR1 were originally obtained from the Institute for Frontier Medical Sciences in Kyoto University and bred in the Faculty of Health and Welfare Science in Okayama Prefectural University. Mice were kept in an air-conditioned room maintained at 25 F 1 jC with humidity of 55 F 5%. The animals were given food and water ad libitum. SAMP1 and SAMR1, 2 to 10 months old, were used. Mice were anesthetized with ether, perfused with 5% formalin solution and excision of the whole brain was performed for histological examination. The hippocampus was isolated and fixed in a buffered 15% formalin solution (pH 7.4) for 3 days, then embedded in paraffin and thin-sectioned at 6 Am. These sections were stained with Bodian’s silver staining and the morphometric analysis of the sections was carried out by measuring the density of neurofibrils or axons, and neurofibrillary tangles were examined with Lumina Vision and MACROSCOPE software (MITANI). Magnolol was isolated from the stem bark of Magnolia obovata in our laboratory, dispersed in a sterilized physiological saline containing 0.5% ethanol and orally admin-
Fig. 1. Changes of the density of the neurofibris and the axons in CA1 and CA3 from 2 to 10 months in mice. Each value is presented as the mean F S.E.M. (n = 3 – 5).
M. Akagi et al. / International Congress Series 1260 (2004) 405–408
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Fig. 2. Effect of magnolol on the density of the neurofibrils and the axons in CA1 and CA3 of SAMP1 mice. Each value is presented as the mean F S.E.M. (n = 3 – 5).
istered at 2 and 5 mg/kg once a day for 7 days to 2-month-old mice. Each value is expressed as means F standard error of the mean (S.E.M). Statistical significance was evaluated by the unpaired Student’s t-test with p < 0.05 regarded as significant. 3. Results Many neurofibrils, axons and cell bodies were observed in the hippocampus. However, when the density of the neurofibris and the axons was measured in CA1 and CA3, it decreased with age from 2 to 10 months. The rate of decrease in SAMP1 was greater than that in SAMR1, and especially the difference between SAMP1 and SAMR1 in CA1 was greater than that in CA3 (Fig. 1). When magnolol was orally administered once a day for 7 days to 2-months-old mice, the decrease of density in CA1 and CA3 regions at 4 months was dose-dependently prevented (Fig. 2). However, until the age of 4 months, SAMP1 animals did not behaviorally differ from SAMR1 either with or without magnolol. 4. Discussion Magnolol possesses potent antioxidant and free radical scavenging activities [2]. Magnolol has been also reported to increase extracelluar acetylcholine release in rat hippocampus [7], and to reduce the increased production of prostaglandin E2 caused by chemical hypoxia in neurons [8]. Brain mitochondrial fraction is characterized by two-fold elevated monoamine oxidase h activity compared to the control line (SAMR1) [9]. The activation of these systems can cause increased generation of reactive oxygen species (ROS) in the SAMP1 brain. At the same age, more intensive accumulation of end products of lipid peroxidation was noted in SAMP1 animals, including lipid hydroperoxides in tissues and increased production of ROS accompanied by increased frequency of chromosomal aberrations in bone stem cells [9].
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M. Akagi et al. / International Congress Series 1260 (2004) 405–408
It has been suggested that imbalance between the rates of generation and utilization of reactive oxygen species and organic free radicals may be one of the main reasons for accelerated aging of SAMP1 animals [9]. These findings suggest that the antioxidant and free radical scavenging activity of magnolol may contribute to the protective effect against neuronal loss in the hippocampus. References [1] C. Taniguchi, M. Homma, Takano, et al., Pharmacological effects of urinary products obtained after treatment with saiboku-to, a herbal medicine for bronchial asthma on type IV allergic reaction, Planta Med. 66 (2000) 607 – 611. [2] Y.M. Lee, G. Hsiao, H.R. Chen, Y.C. Chen, J.R. Sheu, M.H. Yen, Magnolol reduces myocardial ischemia/ reperfusion injury via neutrophil inhibition in rats, Eur. J. Pharmacol. 422 (2001) 159 – 167. [3] Y.C. Lo, C.M. Teng, C.F. Chen, C.C. Chen, C.Y. Hong, Magnolol and honokiol isolated from Magnolia officinalis protect rat heart mitochondria against lipid peroxidation, Biochem. Pharmacol. 47 (1994) 549 – 553. [4] M.H. Lin, H.T. Chao, C.Y. Hong, Magnolol protects human sperm motility against lipid peroxidation: a sperm head fixation method, Arch. Androl. 34 (1995) 151 – 156. [5] S. Takeshita, M. Hosokawa, M. Irino, K. Higuchi, K. Shimizu, K. Yasuhira, T. Takeda, Spontaneous ageassociated amyloidosis in Senescence-Accelerated Mouse (SAM), Mech. Ageing Dev. 20 (1982) 13 – 23. [6] M. Hosokawa, M. Hosono, K. Higuchi, A. Aoike, K. Kawai, T. Takeda, Immune responses in newly developed short-lived SAM mice: I. Age-associated early decline in immune activities of cultured spleen cells, Immunology 62 (1987) 419 – 423. [7] M.T. Hsieh, F.Y. Chueh, S.M. Lin, F.S. Chueh, C.F. Chen, M.T. Lin, Catecholaminergic mechanism-mediated hypothermia induced by magnolol in rats, Jpn. J. Pharmacol. 78 (1998) 501 – 504. [8] M.M. Lee, H.M. Huang, M.T. Hsieh, et al., Anti-inflammatory and neuroprotective effects of magnolol in chemical hypoxia in rat cultured cortical cells in hypoglycemic media, Chin. J. Physiol. 43 (2000) 61 – 67. [9] T. Kawamata, I. Akiguchi, K. Maeda, C. Tanaka, K. Higuchi, M. Hosokawa, T. Takeda, Age-related changes in the brains of senescence-accelerated mice (SAM): association with glial and endothelial reactions, Microsc. Res. Tech. 43 (1998) 59 – 67.
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Neuroprotective effect of magnolol in the hippocampus of senescence-accelerated mice (SAMP1) Masaaki Akagi a,*, Toshimasa Tada a, Akiko Shirono a, Yoshiyasu Fukuyama a, Kousuke Nakade a, Haifeng Zhai a, Yumiko Yasui a, Reiko Akagi b a
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihama-bouji, Yamashiro-cho, Tokushima 770-8514, Japan b Faculty of Health and Welfare Science, Okayama Prefectural University, Kuboki, Souzya 719-1197, Japan Received 19 June 2003; received in revised form 19 June 2003; accepted 10 September 2003
Abstract. We investigated age-dependent neuronal loss in the hippocampus and the protective effect of magnolol using SAMP1 mice in comparison with SAMR1. SAMP1 and SAMR1, 2 to 10 months old, were used. Magnolol (2 and 5 mg/kg) was orally administered once a day for 7 days to 2-monthold mice and evaluation was carried out at 4 months. The density of neurofibrils and axons decreased with aging in the CA1 and CA3 regions of the hippocampus. The rate of decrease in SAMP1 was greater than that of SAMR1. Treatment with magnolol dose-dependently prevented the decrease of density in CA1 and CA3 at 4 months. However, until the age of 4 months, SAMP1 animals did not behaviorally differ from SAMR1 either with or without magnolol. It has been suggested that imbalance between the rates of generation and utilization of reactive oxygen species (ROS) and organic free radicals may be one of the main reasons for accelerated aging of SAMP1 animals. These findings suggest that the antioxidant and free radical scavenging activity of magnolol may contribute to the protective effect against neuronal loss in the hippocampus. D 2003 Elsevier B.V. All rights reserved. Keywords: Magnolol; Hippocampus; Senescence; SAMP1
1. Introduction Magnolol (5,5V-di-2-propenyl-1,1V-biphenyl-2,2V-diol), which was originally extracted from the Chinese medicinal herb Magnolia officinalis, in used as an anti-allergy and anti-asthma compound with a wide spectrum of pharmacological activities [1]. Magnolol possesses potent antioxidant and free radical scavenging activities [2]. It has also been reported to be 1000 times more potent than alpha-tocopherol in inhibiting * Corresponding author. Tel.: +81-88-622-9611; fax: +81-88-655-3051. E-mail address: [email protected] (M. Akagi). 0531-5131/ D 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0531-5131(03)01679-0
406
M. Akagi et al. / International Congress Series 1260 (2004) 405–408
lipid peroxidation in rat heart mitochondria and 50 000 times more potent than glutathione in reversing the iron-induced reduction of beating frequency in the human sperm tail [3,4]. The SAMP1 mouse, separated from several SAMP strains, is characterized by senile amyloidosis and age-related decline in antibody-forming capacity [5,6]. In the present study, we investigated the age-dependent neuronal loss in the hippocampus and the protective effect of magnolol using SAMP1 in comparison with SAMR1. 2. Materials and methods All experiments were conducted in accordance with the Guiding Principles for the Care and Use of Laboratory Animals approved by The Japanese Pharmacological Society. The substrains of SAM, SAMP1 and SAMR1 were originally obtained from the Institute for Frontier Medical Sciences in Kyoto University and bred in the Faculty of Health and Welfare Science in Okayama Prefectural University. Mice were kept in an air-conditioned room maintained at 25 F 1 jC with humidity of 55 F 5%. The animals were given food and water ad libitum. SAMP1 and SAMR1, 2 to 10 months old, were used. Mice were anesthetized with ether, perfused with 5% formalin solution and excision of the whole brain was performed for histological examination. The hippocampus was isolated and fixed in a buffered 15% formalin solution (pH 7.4) for 3 days, then embedded in paraffin and thin-sectioned at 6 Am. These sections were stained with Bodian’s silver staining and the morphometric analysis of the sections was carried out by measuring the density of neurofibrils or axons, and neurofibrillary tangles were examined with Lumina Vision and MACROSCOPE software (MITANI). Magnolol was isolated from the stem bark of Magnolia obovata in our laboratory, dispersed in a sterilized physiological saline containing 0.5% ethanol and orally admin-
Fig. 1. Changes of the density of the neurofibris and the axons in CA1 and CA3 from 2 to 10 months in mice. Each value is presented as the mean F S.E.M. (n = 3 – 5).
M. Akagi et al. / International Congress Series 1260 (2004) 405–408
407
Fig. 2. Effect of magnolol on the density of the neurofibrils and the axons in CA1 and CA3 of SAMP1 mice. Each value is presented as the mean F S.E.M. (n = 3 – 5).
istered at 2 and 5 mg/kg once a day for 7 days to 2-month-old mice. Each value is expressed as means F standard error of the mean (S.E.M). Statistical significance was evaluated by the unpaired Student’s t-test with p < 0.05 regarded as significant. 3. Results Many neurofibrils, axons and cell bodies were observed in the hippocampus. However, when the density of the neurofibris and the axons was measured in CA1 and CA3, it decreased with age from 2 to 10 months. The rate of decrease in SAMP1 was greater than that in SAMR1, and especially the difference between SAMP1 and SAMR1 in CA1 was greater than that in CA3 (Fig. 1). When magnolol was orally administered once a day for 7 days to 2-months-old mice, the decrease of density in CA1 and CA3 regions at 4 months was dose-dependently prevented (Fig. 2). However, until the age of 4 months, SAMP1 animals did not behaviorally differ from SAMR1 either with or without magnolol. 4. Discussion Magnolol possesses potent antioxidant and free radical scavenging activities [2]. Magnolol has been also reported to increase extracelluar acetylcholine release in rat hippocampus [7], and to reduce the increased production of prostaglandin E2 caused by chemical hypoxia in neurons [8]. Brain mitochondrial fraction is characterized by two-fold elevated monoamine oxidase h activity compared to the control line (SAMR1) [9]. The activation of these systems can cause increased generation of reactive oxygen species (ROS) in the SAMP1 brain. At the same age, more intensive accumulation of end products of lipid peroxidation was noted in SAMP1 animals, including lipid hydroperoxides in tissues and increased production of ROS accompanied by increased frequency of chromosomal aberrations in bone stem cells [9].
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M. Akagi et al. / International Congress Series 1260 (2004) 405–408
It has been suggested that imbalance between the rates of generation and utilization of reactive oxygen species and organic free radicals may be one of the main reasons for accelerated aging of SAMP1 animals [9]. These findings suggest that the antioxidant and free radical scavenging activity of magnolol may contribute to the protective effect against neuronal loss in the hippocampus. References [1] C. Taniguchi, M. Homma, Takano, et al., Pharmacological effects of urinary products obtained after treatment with saiboku-to, a herbal medicine for bronchial asthma on type IV allergic reaction, Planta Med. 66 (2000) 607 – 611. [2] Y.M. Lee, G. Hsiao, H.R. Chen, Y.C. Chen, J.R. Sheu, M.H. Yen, Magnolol reduces myocardial ischemia/ reperfusion injury via neutrophil inhibition in rats, Eur. J. Pharmacol. 422 (2001) 159 – 167. [3] Y.C. Lo, C.M. Teng, C.F. Chen, C.C. Chen, C.Y. Hong, Magnolol and honokiol isolated from Magnolia officinalis protect rat heart mitochondria against lipid peroxidation, Biochem. Pharmacol. 47 (1994) 549 – 553. [4] M.H. Lin, H.T. Chao, C.Y. Hong, Magnolol protects human sperm motility against lipid peroxidation: a sperm head fixation method, Arch. Androl. 34 (1995) 151 – 156. [5] S. Takeshita, M. Hosokawa, M. Irino, K. Higuchi, K. Shimizu, K. Yasuhira, T. Takeda, Spontaneous ageassociated amyloidosis in Senescence-Accelerated Mouse (SAM), Mech. Ageing Dev. 20 (1982) 13 – 23. [6] M. Hosokawa, M. Hosono, K. Higuchi, A. Aoike, K. Kawai, T. Takeda, Immune responses in newly developed short-lived SAM mice: I. Age-associated early decline in immune activities of cultured spleen cells, Immunology 62 (1987) 419 – 423. [7] M.T. Hsieh, F.Y. Chueh, S.M. Lin, F.S. Chueh, C.F. Chen, M.T. Lin, Catecholaminergic mechanism-mediated hypothermia induced by magnolol in rats, Jpn. J. Pharmacol. 78 (1998) 501 – 504. [8] M.M. Lee, H.M. Huang, M.T. Hsieh, et al., Anti-inflammatory and neuroprotective effects of magnolol in chemical hypoxia in rat cultured cortical cells in hypoglycemic media, Chin. J. Physiol. 43 (2000) 61 – 67. [9] T. Kawamata, I. Akiguchi, K. Maeda, C. Tanaka, K. Higuchi, M. Hosokawa, T. Takeda, Age-related changes in the brains of senescence-accelerated mice (SAM): association with glial and endothelial reactions, Microsc. Res. Tech. 43 (1998) 59 – 67.