Effects of black cohosh and estrogen on core body and tail-skin temperatures in ovariectomized rats by telemetric monitoring with dual thermistor probes

Mapping the 5-HTergic neural pathways in perimenopausal mice and elucidating the role of oestrogen receptors in 5-HT neurotransmission

Perimenopausal syndrome (PMS) encompasses neuropsychiatric symptoms, such as hot flashes and depression, which are associated with alterations in the 5-HTergic neural pathway in the brain. However, the specific changes and mechanisms underlying these alterations remain unclear. In this study, ovariectomized mice were used to successfully establish a perimenopause model, and the changes in the expression of 5-HT and its receptors (5-HT1AR and 5-HT2AR) across 72 brain regions in these ovariectomized mice were assessed by immunohistochemistry. Although both 5-HT and 5-HT1AR were widely expressed throughout the brain, only a limited number of regions expressed 5-HT2AR. Notably, decreased expression of 5-HT was observed across almost all brain regions in the ovariectomy (OVX) group compared with the Sham group. Altered expression of both receptors was found within areas related to hot flashes (the preoptic area) or mood disorders (the amygdala). Additionally, reduced oestrogen receptor (ER)α/β expression was detected in cells in the raphe nucleus (RN), an area known to regulate body temperature. Results showed that ERα/β positively regulate the transcriptional activity of the enzymes TPH2/MAOA, which are involved in serotonin metabolism during perimenopause. This study revealed the changes in 5-HT neuropathways (5-HT, 5-HT1AR and 5-HT2AR) in perimenopausal mice, mainly in brain regions related to regulation of the body temperature, mood, sleep and memory. This study clarified that the expression of oestrogen receptor decreased in perimenopause, which regulated the transcription levels of TPH2 and MAOA, and ultimately led to the reduction of 5-HT content, providing a new target for clinical diagnosis and treatment of perimenopausal diseases.

Ameliorative effects of Kyung-Ok-Ko and its mixture with Pueraria lobata Ohwi on postmenopausal osteoporosis by promoting phytoestrogenic activity in rats

Introduction

Kyung-Ok-Ko (KOK) is a popular traditional medicine used as a natural alternative to hormone replacement therapy for treating postmenopausal symptoms in Asia. Pueraria lobata Ohwi (P. lobata) is rich in isoflavones and has been traditionally used in combination with other herbs to produce synergistic and pharmaceutical effects via a multi-target approach for disease treatment. We aimed to investigate the phytoestrogenic effects of KOK extract against postmenopausal symptoms in ovariectomized (OVX) rats and confirm its efficacy by mixing KOK and P. lobata extracts.

Methods

OVX rats were daily oral administrated with KOK and KOK + P. lobata mixture extracts (300-400 mg/kg) and their body weight and tail temperature were monitored for 12 weeks. The biochemical parameters, estradiol levels, and bone turnover markers were measured in the serum samples. Moreover, the estrogen receptor, ER-α and ER-β expression in the uterus and the uterus morphology were evaluated. AMPK, ATG1/ULK1, and mTOR protein expression in the liver were assessed.

Results

The 12-week treatment with KOK and KOK + P. lobata mixture extracts did not cause liver damage or hormonal changes in the OVX rats. The treatments reduced the high lipid accumulation-related body weight gain and the tail temperature increase that was induced by ovariectomy. Further, it exhibited protective effects against hyperlipidemia and osteoporosis. No significant difference was observed in uterine weight compared to the OVX-treated group, while endometrial thickness reduction inhibition was observed due to ovariectomy. Bone mineral density (BMD) and serum osteocalcin levels, which decreased in OVX rats, increased with both treatments. Western blotting analysis showed that ER-α and ER-β were not expressed in the treated rats, whereas these proteins were expressed in Sham-operated rats. No significant differences in the phosphorylation of AMPK were observed; however, the ATG1/ULK1 and mTOR protein phosphorylation levels were upregulated and downregulated in the treated rats compared to those of OVX rats, respectively.

Conclusion

This is the first in vivo study observing the efficacy and synergistic effects of the mixture of KOK and P. lobata. Our results suggest the potential of KOK and KOK + P. lobata mixture as an alternative therapy for alleviating menopausal symptoms.

Changes in skin temperature of ovariectomized rats under different incubation temperatures

AIM

This study aimed to investigate changes in skin temperature in the main body regions of ovariectomized rats under different incubation temperatures to identify regions that are similar to hot flashes experienced by menopausal women.

METHODS

A total of 96 adult female Sprague-Dawley rats were randomly divided into sham, ovariectomized and ovariectomized with estrogen treatment groups, with treatment lasting for 4 weeks. After 3 weeks of treatment, each group was randomly divided into five subgroups and placed in separate incubators set at 4, 15, 25, and 37°C. Changes in the skin temperature in seven main regions (head, neck, chest, abdomen, back, tail, and paws) for four time intervals (0-3 min, 3-5 min, 5-10 min and 10-15 min) were monitored using infrared thermography.

RESULTS

All rats showed rapid changes in skin temperature followed by a gradual slowdown under different incubation temperatures. However, changes in ovariectomized rats were significantly different from that in normal rats, and changes on the back, tail and paws were more rapid and lasted longer. Estrogen treatment effectively controlled these abnormalities of ovariectomized rats.

CONCLUSIONS

Temperature responses in the back, tail and paws in ovariectomized rats might be similar to the face, neck and upper chest in menopausal women, where the symptoms of hot flashes are most obvious, which suggests that the back, tail and paws could be regarded as the focus of research on hot flashes, and offer theoretical foundations for mechanisms behind the occurrence of hot flashes in specific regions. Geriatr Gerontol Int 2020; ••: ••-••.