Pubertal immune stress transiently alters spatial memory processes in adulthood.

Area of Science:

• Neuroscience
• Immunology
• Endocrinology

Background:

• Pubertal immune challenges can cause lasting cognitive changes, particularly in hippocampus-dependent memory.
• The role of gonadal hormones in mediating these cognitive effects after pubertal immune challenges is not fully understood.

Purpose of the Study:

• To investigate if pubertal immune challenge affects adult hippocampus-dependent memory.
• To determine if gonadal steroid hormones regulate these cognitive alterations.
• To explore sex-specific effects of pubertal immune challenge on memory and neurogenesis.

Main Methods:

• Mice received lipopolysaccharide (LPS) or saline during puberty, followed by gonadectomy or sham surgery.
• Adult cognitive function was assessed using open field, Barnes maze, and Morris water maze tests.
• Hippocampal tissue was analyzed for neurogenesis and cellular proliferation markers.

Main Results:

• Pubertal LPS exposure impaired adult learning in both sexes.
• Castrated males showed increased CA1 cellular proliferation post-LPS.
• Gonadectomy worsened Morris water maze performance, and Barnes maze deficits were more pronounced, suggesting stress-dependency.

Conclusions:

• Cognitive processes during puberty are sensitive to immune challenges, potentially leading to adult learning difficulties.
• Gonadal hormones may play a role, but stress appears to exacerbate LPS-induced cognitive deficits.
• Specific hippocampal regions and neurogenesis markers were differentially affected by pubertal immune challenge and gonadectomy.