Comparative Analysis of HPA-Axis Dysregulation and Dynamic Molecular Mechanisms in Acute Versus Chronic Social Defeat Stress

Prolonged stress-related hormonal signaling can reduce the ability of the immune system to maintain balance, which may lead to a higher likelihood of autoimmune conditions.

In male mice, prolonged social stress is linked to lower levels of GABA and higher levels of glutamate in a brain region called the hypothalamus, which may disrupt normal brain signaling and lead to lasting anxiety-like behaviors, similar to changes seen in humans with major depression.

When male mice experience a short, intense social stress, specific genes and inflammatory molecules become active across key stress-response organs—hypothalamus, pituitary, and adrenal gland—but this activity stops within a day and does not occur with long-term stress.

In male mice, prolonged social stress reduces the production of the stress hormone corticosterone in the adrenal gland by decreasing the activity of specific enzymes involved in its synthesis, whereas short-term stress temporarily increases corticosterone levels, suggesting a change in how the stress response system functions over time.

In male mice, prolonged exposure to social stress leads to increased activity in specific immune-related molecules in the brain region that regulates emotion, and this change is linked to lasting behaviors that resemble anxiety.