Changes in the Histomorphometric and Biomechanical Properties of the Proximal Femur of Ovariectomized Rat after Treatment with the Phytoestrogens Genistein and Equol

Mohammad Tezval; Stephan Sehmisch; Dana Seidlová-Wuttke; Thomas Rack; Leila Kolios; Wolfgang Wuttke; Klaus Michael Stuermer; Ewa Klara Stuermer

doi:10.1055/s-0029-1186136

Planta Medica, Table of Contents

Planta Med 2010; 76(3): 235-240
DOI: 10.1055/s-0029-1186136

Pharmacology

Original Papers
© Georg Thieme Verlag KG Stuttgart · New York

Changes in the Histomorphometric and Biomechanical Properties of the Proximal Femur of Ovariectomized Rat after Treatment with the Phytoestrogens Genistein and Equol

Mohammad Tezval¹ , Stephan Sehmisch¹ , Dana Seidlová-Wuttke² , Thomas Rack¹ , Leila Kolios¹ , Wolfgang Wuttke² , Klaus Michael Stuermer¹ , Ewa Klara Stuermer¹

¹Department of Trauma Surgery, Plastic and Reconstructive Surgery, Georg-August-University of Goettingen, Goettingen, Germany
²Department of Clinical and Experimental Endocrinology, Georg-August-University of Goettingen, Goettingen, Germany

Abstract

The isoflavonoids found in soy have attracted great interest as dietary phytoestrogens that might be effective for postmenopausal hormone replacement therapy. Special attention has been devoted to the hormonal effects of various isoflavonoids, like genistein (GEN) and daidzein's (DAID) potent metabolite, equol (EQ). Here we aimed to investigate the short-term effects of genistein and equol on the proximal femur of ovariectomized (OVX) rats. Forty-eight, 3-month-old female Sprague-Dawley rats were ovarectomized; after eight weeks the bilateral osteotomy and osteosynthesis (OS) of their tibiae was performed and the rats were randomly divided into the following four groups: OVX control group (C), treated with estradiol-17beta (E2) ‐benzoate (E; daily intake 0.086 mg/d per animal), genistein (GEN; daily intake 12.7 mg/d per animal) and equol (EQ; daily intake 4.65 mg/d per animal). At 5 weeks postoperatively (OS), the breaking test was performed on the trochanteric region of femur. Additionally, histomorphometric assessment, and trabecular and cortical bone microstructure analyses were performed. The relative gain of body weight (BW) in the EQ (24 %) group was significantly (p < 0.05) lower than in the C (33 %) and GEN (30 %) groups. After treatment for 5 weeks, the maximal load (F_max) and yield load (yL) were higher (p < 0.05 for the weight-adapted results) in the E (188.4 N resp. 113.1 N) and EQ (177.3 N resp. 112 N) groups as compared to C (162.8 N resp. 109.1 N) and GEN (165.7 N resp. 108.8 N). In the histomorphometric tests the E- (trabecular area (Tb.Ar) = 74.93 %, trabecular nodes/mm² (N.Nd/mm²) = 48.65) and EQ-treated (Tb.Ar = 63.13 %, N.Nd/mm² = 43.72) animals showed significant improvement with regard to Tb.Ar and trabecular connectivity (N.Nd./mm²) in comparison to C (Tb.Ar = 46.84, N.Nd/mm² = 31.86) and GEN (Tb.Ar = 48.22 %, N.Nd/mm² = 34.15). There were no differences in relative cortical width (Ct.Wi) among the four groups. The treatment with EQ resulted in improved biomechanical and histomorphometric properties as compared to the treatment with GEN. Thus, of the studied substances, EQ seems to be a possible alternative to hormone replacement therapy, but further studies are needed.

Key words

osteoporosis - rat femur - isoflavonoids - genistein - equol - biomechanical test

Full Text

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Dr. Mohammad Tezval

Department of Trauma Surgery, Plastic and Reconstructive Surgery
Georg-August-University Hospital

Robert Koch Str. 40

37075 Goettingen

Germany

Phone: + 49 5 51 39 61 14

Fax: + 49 5 51 39 89 81

Email: mtezval@med.uni-goettingen.de