Effects of the special Cimicifuga racemosa extract BNO 1055 on hot flashes on ovariectomized rats

Hot flashes occur due to the lack of estrogens and are the most common climacteric complaint. Hormone replacement therapy is the gold standard treatment but now its use is limited due to severe side effects. It is well established that extracts of Cimicifuga racemosa (CR) ease climacteric complaints but solid animal experimental data supporting such effects are not available. The availability of temperature sensitive transponders enables experiments in rats to establish whether they have hot flashes following ovariectomy (ovx) and if so, whether they can be influenced by the extract CR BNO 1055. Intact Sprague Dawley rats (n=16) were implanted with transponders under the skin of the nape. Subcutaneous temperature was measured in 5min intervals for 3h. Thereafter, the rats were ovx and fed either with soy free (sf) or CR BNO 1055 (11.3mg/animal/day) food. Temperature was recorded again after acute and sub-acute application of CR. In intact animals temperature was stable over the 3h recording period. Following ovx temperature pulses appeared with peaks occurring every 20–40min. These fluctuations were not seen in intact or CR BNO 1055 treated animals resulting in significantly higher mean temperatures. The reduction of hot flashes by BNO 1055 outlasted the experimental period of 3 weeks. These results suggest that the ovx rats and the new temperature sensitive transponders may be useful for the study of hot flashes. Furthermore they prove that the CR BNO 1055 exerts hot flash reducing effects.