Acta Pharmacologica Sinica 2006 January; 27 (1): 50-58; doi: 10.1111/j.1745-7254.2006.00252.x

Acta Pharmacologica Sinica 2006 January; 27 (1): 59-65; doi: 10.1111/j.1745-7254.2006.00258.x

Original Article

Soybean isoflavones alter parvalbumin in hippocampus of mid-aged normal female, ovariectomized female, and normal male rats¹

In Koo HWANG^2,7, Yoon-bok LEE^{3, 7}, Ki-yeon YOO², Tae-cheon KANG², Soon Sung LIM⁴, Sang Moo KIM⁵, Heon-soo SOHN³, Woo-jung KIM⁶, Hyun Kyung SHIN⁴, Moo Ho WON^{2,8 2}

Department of Anatomy, College of Medicine, Hallym University, Chunchon 200-702, Korea; ³Department of Laboratory Animal Research, Central Research Institute, Dr Chung's Food Co Ltd, Cheongju 361-782, Korea; ⁴Division of Life Science and Silver Biotechnology Research Center, Hallym University, Chunchon 200-702, Korea; ⁵Faculty of Marine Bioscience and Technology, Kangneung National University, Kangneung 210-702, Korea; ⁶Faculty of Food Science and Technology, College of Life Sciences, Sejong University, Sejong 143-747, Korea

Aim: To investigate the long-term effect of soybean isoflavones on changes in parvalbumin (PV) immunoreactivity in the hippocampus in normal female, ovariectomized (OVX) female and normal male rats.

Methods: Ten-month-old rats were assigned to one of 9 groups (n=7 in each group) based on body weight using a randomized complete-block design. The groups were: control diet-treated females, OVX females, and males; 0.3 g/kg isoflavone-treated females, OVX females, and males; and 1.2 g/kg isoflavone-treated females, OVX females, and males. The PV immunostaining was conducted by using the standard avidin-biotin complex method.

Results: PV immunoreactivity and the number of PV-immunoreactive neurons in all the groups after isoflavone treatment were significantly changed in the hippocampal CA1 region and in the dentate gyrus, but not in the hippocampal CA2/3 region. PV immunoreactivity and the number of PV-immunoreactive neurons in the control diet OVX females were similar to those in the control diet, and were greater than those in the control diet normal females. PV immunoreactivity and the number of PV-immunoreactive neurons in all the isoflavone-treated groups decreased dose-dependently after isoflavone treatment.

Conclusion: Long-term administration of isoflavones may induce a reduction of PV in interneurons in the hippocampal CA1 region and in the dentate gyrus. The reduction of PV in these regions suggests that the long-term administration of isoflavones may cause a change in calcium homeostasis in the hippocampal CA1 region and in the dentate gyrus.

Keywords: isoflavones; ovariectomy; hippocampus; immunohistochemistry

¹Project supported by the Technology Development Program for Agriculture and Forestry, Ministry of Agriculture and Forestry (202015-03-2-CG000), and Repu-blic of Korea, Korea Science and Engineering through the Silver Biotechnology Research Center at Hallym University (R12-2001-047-02003-0). This work was also supported by a grant from Hallym Univer-sity, Korea.

⁷These authors contributed equally to this article.
⁸Correspondence to Prof Moo Ho WON.
Phn 82-33-248-2522.
Fax 82-33-256-1614.
E-mail mhwon@hallym.ac.kr
Received 2005-07-20 Accepted 2005-09-28

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