Changes in skin temperature of ovariectomized rats under different incubation temperatures

Effects of Guizhi and Erxian Decoction on menopausal hot flashes: insights from the gut microbiome and metabolic profiles

AIMS

To examine the influence of GED on the gut microbiota and metabolites using a bilateral ovariectomized (OVX) rat model. We tried to elucidate the underlying mechanisms of GED in the treatment of menopausal hot flashes.

METHODS AND RESULTS

16S rRNA sequencing, metabonomics, molecular biological analysis, and fecal microbiota transplantation (FMT) were conducted to elucidate the mechanisms by which GED regulates the gut microbiota. GED significantly reduced OVX-induced hot flashes and improved disturbances in the gut microbiota metabolites. Moreover, FMT validated that the gut microbiota can trigger hot flashes, while GED can alleviate hot flash symptoms by modulating the composition of the gut microbiota. Specifically, GED upregulated the abundance of Blautia, thereby increasing l(+)-ornithine levels for the treatment of menopausal hot flashes. Additionally, GED affected endothelial nitric oxide synthase and heat shock protein 70 (HSP70) levels in the hypothalamic preoptic area by changing the gut microbiota composition.

CONCLUSIONS

Our study illuminated the underlying mechanisms by which GED attenuated the hot flashes through modulation of the gut microbiota and explored the regulatory role of the gut microbiota on HSP70 expression in the preoptic anterior hypothalamus, thereby establishing a foundation for further exploration of the role of the gut-brain axis in hot flashes.

Transient receptor potential M2 channel in the hypothalamic preoptic area and its impact on thermoregulation during menopause

BACKGROUND

Decreased estrogen levels can cause abnormal thermosensitivity of the preoptic area (POA) in the hypothalamus during menopause, which may cause hot flashes. Thermosensitive transient receptors (ThermoTRPs) affect the thermosensitivity of neurons. It is worth exploring whether ThermoTRPs change under low estrogen state and participate in the abnormal thermoregulation of POA.

METHODS

Adult female Sprague-Dawley rats were randomly divided into sham operation (SHAM), ovariectomy (OVX) and estrogen treatment after ovariectomy (OVX+E) groups. Under 10 ℃, 18 ℃, 25 ℃, 37 ℃ and 45 ℃ incubations, their skin temperature was monitored and the expression of TRPA1, TRPM8, TRPM2, and TRPV1 in POA were investigated.

RESULTS

The skin temperature of ovariectomized rats changed faster and more dramatically under different incubation temperatures. The results at mRNA level show that only the expression of TRPM2 decreased in POA of OVX group compared with the other two groups at 25 ℃, TRPA1 expression in POA of the three groups increased at 10 ℃, TRPM8 increased at 10 ℃ and 18 ℃, TRPV1 increased at 10 ℃ and 45 ℃, while the expression of TRPM2 decreased at 10 ℃ and 18 ℃ and increased at 37 ℃ and 45 ℃. In all these cases, the magnitudes of the changes were less in the OVX group relative to the other two groups. The further immunohistochemical and Western blot results of TRPM2 and the activated TRPM2 positive cells labeled by c-Fos were consistent with the results of mRNA level.

CONCLUSIONS

The expression and thermosensitivity of TRPM2 in POA changed greatly under different incubation temperatures, but the changes in ovariectomized rats were less. This may be the key factor triggering thermoregulation dysfunction under low estrogen and may cause hot flashes.

Bubble plastic use in rats hernioplasty: Uso do plástico bolha em hernioplastias de ratos

Purpose

Despite the high frequency of hernioplasties worldwide, their complications and recurrences are still a challenge to be overcome. The search for prostheses that aim to promote the correction of hernia defects has been a challenge. For this purpose, the materials used in hernioplasties must be biocompatible, promote the formation of little or no peritoneal adhesion, possess compatible texture and flexibility, providing the necessary resistance to protect the viscera and allow the movement of the abdomen.

Methods

The aim of the present study was to evaluate the effectiveness of bubble plastic (low density polyethylene, LDPE) as a material for the correction of hernia in the abdominal wall. For this, twenty male rats (Rattus norvegicus, Wistar variety) were used and divided into four groups of five animals. The animals were evaluated at 7, 15, 30 and 90 days after surgery according to clinical, thermographic and morphological parameters (macroscopic and microscopic).

Results

The results showed that the bubble plastic induced inflammatory reaction in the initial period (7 day), followed by a reduction (30 day) to increase considerably at 90 days after the operation.

Conclusion

So, bubble plastic can be used for temporary implants (up to 30 days).

Transient Receptor Potential Melastatin 2 Thermosensitive Neurons in the Preoptic Area Involved in Menopausal Hot Flashes in Ovariectomized Mice

INTRODUCTION

Menopausal hot flashes are related to hypothalamic preoptic area (POA) dysfunction. Thermosensitive transient receptor potential channels (ThermoTRPs) are involved in temperature sensing and regulation of thermosensitive neurons (TSNs) in the POA. Whether ThermoTRP-TSNs in the POA, particularly the non-noxious thermoreceptor, transient receptor potential melastatin 2 (TRPM2), are involved in the occurrence of hot flashes is still unclear.

METHODS

Twenty wild-type and 50 Trpm2-Cre adult female mice were randomly divided into sham (SHAM) and ovariectomy (OVX) groups. In the POA, ERα, ERβ, GPR30, TRPA1, TRPM8, TRPM2, and TRPV1 expression was detected by Western blot or/and quantitative real-time polymerase chain reaction and the number of TSNs expressing TRPM2 (TRPM2-TSNs) by immunofluorescence. Before and after TRPM2-TSN activation/inhibition, back (BST) and tail skin temperature (TST) and the proportion of glutamatergic and GABAergic neurons among TRPM2-TSNs were recorded.

RESULTS

Compared with SHAM, the expression of ERα, ERβ, TRPM2, and TRPM8 in the POA of the OVX group decreased, with a significantly larger change range for TRPM2 than TRPM8. In addition, the number of TRPM2-TSNs showing TRPA1, TRPM8, and TRPV1 expression in the OVX group decreased, and the proportion of glutamatergic and GABAergic neurons in TRPM2-TSNs decreased and increased, respectively. Meanwhile, BST and TST increased. After activating or inhibiting TRPM2-TSNs, the proportions of glutamatergic and GABAergic neurons in TRPM2-TSNs changed, along with the BST and TST.

CONCLUSION

In menopause, the abnormal quantity and function of TRPM2-TSNs in the POA is key for the development of hot flashes, characterized by an imbalance in heat dissipation and production due to the corresponding imbalance in glutamatergic and GABAergic neurons.