Depression is a common and severely debilitating neuropsychiatric disorder. Multiple studies indicate a strong correlation between the occurrence of immunological inflammation and the presence of depression. The basolateral amygdala (BLA) is crucial in the cognitive and physiological processing and control of emotion. However, due to the lack of detection tools, the neural activity of the BLA during depression is not well understood. In this study, a microelectrode array (MEA) based on the shape and anatomical location of the BLA in the brain was designed and manufactured. Rats were injected with lipopolysaccharide (LPS) for 7 consecutive days to induce depressive behavior. We used the MEA to detect neural activity in the BLA before modeling, during modeling, and after LPS administration on 7 consecutive days. The results showed that after LPS treatment, the spike firing of neurons in the BLA region of rats gradually became more intense, and the local field potential power also increased progressively. Further analysis revealed that after LPS administration, the spike firing of BLA neurons was predominantly in the theta rhythm, with obvious periodic firing characteristics appearing after the 7 d of LPS administration, and the relative power of the local field potential in the theta band also significantly increased. In summary, our results suggest that the enhanced activity of BLA neurons in the theta band is related to the depressive state of rats, providing valuable guidance for research into the neural mechanisms of depression.

Menopausal hormone therapy (MHT) has been widely used for the clinical treatment of symptoms associated with menopause in women. However, the exact nature of the relationship between MHT and the increased risk of breast cancer has not been fully elucidated. The results of the Women’s Health Initiative’s randomized controlled clinical studies showed that estrogen monotherapy was associated with a lower incidence of breast cancer as compared to estrogen-progesterone combined therapy, with an elevated risk of breast cancer. The evidence currently available from randomized trials and observational studies is based on data from different populations, drug formulations, and routes of administration. Even though the risks of MHT and breast cancer have received a great deal of attention, information regarding the unpredictable toxicological risks of estrogen and progestogen metabolism needs to be further analyzed. Furthermore, the diversity and complexity of the metabolic pathways of estrogen and different progestogens as well as the association of the different estrogen and progestogen metabolites with the increased risk of breast cancer need to be adequately studied. Therefore, this review aimed to describe the biological effects of estrogen, progesterone, and their metabolites on the proliferation of breast cancer cells, based on relevant basic research and clinical trials, to improve our understanding of the biological functions of estrogen and progestogen as well as the safety of MHT.