Effect of daidzein, 4-methylbenzylidene camphor or estrogen on gastrocnemius muscle of osteoporotic rats undergoing tibia healing period

Abstract

The effect of daidzein (D), 4-methylbenzylidene camphor (4-MBC) or estradiol-17b-benzoate (E 2 ) on muscle of osteoporotic rats during fracture healing was studied. After performing a metaphyseal tibia osteotomy in 96 osteoporotic 5-month-old female Sprague-Dawley rats, they received daily 50 mg D, 200 mg 4-MBC or 0 . 4 mg E 2 per kg body weight, or soy free (SF) diet up to 36 and 72 days. Mitochondrial activity, fiber area, and capillary density were analyzed in M. gastrocnemius. Osseous callus bridging of fracture was observed in half of the rats after 36 days. By day 72, fracture was healed in most of the animals. State 3 mitochondrial respiration significantly enhanced in E 2 , 4-MBC and D groups versus SF after 36 days (30, 32 and 32 vs 23 pmol O 2 /s per mg). It declined after 72 days, however, in E 2 group it was still at a higher level versus SF (25, 23 and 21 vs 20 pmol O 2 /s per mg). Size of fast oxidative glycolytic (FOG) and fast glycolytic (FG) fibers, capillary density did not differ significantly between the groups, however, at day 36 an increase in D and 4-MBC groups was detectable. FOG diameter was 64, 66, 68, and 58 mm and FG diameter was 88, 98, 95, and 89 mm in SF, D, 4-MBC, and E 2 groups. The ratio of capillaries to muscle fiber was 1 . 1, 1 . 4, 1 . 3, and 1 . 1 in SF, D, 4-MBC and E 2 groups by day 36. D and 4-MBC react similar to estrogen thereby improving oxidative cell metabolism in severe osteoporotic rats. The level of mitochondrial activity was higher, though no significant morphological differences could be shown.

Impact of 4-methylbenzylidene camphor, daidzein, and estrogen on intact and osteotomized bone in osteopenic rats

“…and 4-MBC groups. Estrogen supplementation increased uterine weight significantly, whereas daidzein and 4-MBC supplementation showed no effect (Komrakova et al 2009). Treatment with 4-MBC or E 2 resulted in an enhanced BMD of vertebral body after 10 weeks, whereas calcium to orthophosphate ratio was increased after both 5 and 10 weeks.…”

“…This paper also included preliminary qualitative analysis of tibia healing. Lower rates of complete healing were detected in rats treated with 4-MBC and estrogen compared with daidzein-treated rats or untreated Ovx rats (Komrakova et al 2009). …”

“…They are already commercially available as a dietary supplement, though they may have the potential for effectively functioning as endocrine disruptors (Mueller et al 2004). Daidzein and genistein are the prevalent phytoestrogens in soy and are under investigation because of their estrogen-like effect (Picherit et al 2000, Setchell & Lydeking-Olsen 2003, Komrakova et al 2009). Genistein has been demonstrated to inhibit bone resorption and stimulate bone mineralization; however, it was not favorable for tibia healing (Setchell & Lydeking-Olsen 2003, Kolios et al 2009).…”

“…Though 4-MBC has been reported to be an endocrine disruptor (Carou et al 2009), it is approved for use in the European Union for cosmetic products and non-food products. 4-MBC is relevant not only from a toxicological point of view but is also interesting because of its protective effect on osteoporotic bone and muscle , Komrakova et al 2009). …”

“…However, the impact of these substances on the healing processes of fractured bone has not been studied so far. Part of this study has been presented in Komrakova et al (2009) showing a positive effect of estrogen, 4-MBC, and daidzein on muscle tissue. This paper also included preliminary qualitative analysis of tibia healing.…”