Prolonged isolation may induce stress related bone loss, finds study

In order to identify the neural mechanism underlying chronic stress-induced bone loss, the research team used a mouse model where mice were subjected to unpredictable chronic mild stress.

They found that after four to eight weeks of chronic stress, the mice displayed significant anxiety behaviors. The bone mineral density of the mice in the stress group was significantly lower than in the control group.

These results confirmed the correlation between stress-induced anxiety and bone loss in experimental animals, and provided a good animal model for follow-up neural mechanism analysis.

Through extensive experiments, researchers identified a population of inhibitory neurons expressing somatostatin in the brain nucleus that are known as the bed nucleus of the stria terminalis (BNST) in the forebrain. These neurons were activated when animals showed anxiety behaviors and transmitted "anxiety" information to the neurons in the ventromedial hypothalamus (VMH).

"Activating the BNST-VMH neural circuit can simultaneously induce anxiety-like behaviors and generate bone loss in the mice, whereas inhibition of this circuit can prevent stress-induced anxiety and bone loss at the same time," said Prof. YANG Fan from SIAT, the co-first and co-corresponding author of the study.

Furthermore, the researchers discovered that glutamatergic neurons in nucleus tractus solitaries (NTS) and the sympathetic system were employed to regulate stress-induced bone loss.

"This study provides a new perspective for the systematic study of the regulatory mechanism of brain homeostasis on metabolism and endocrine function of the body in special environments," said Prof. WANG Liping, Director of the Brain Cognition and Brain Disease Institute of SIAT.

https://www.jci.org/articles/view/136105