IGF-I Gene Therapy in Aging Rats Modulates Hippocampal Genes Relevant to Memory Function

Area of Science:

• Neuroscience
• Genetics
• Aging Research

Background:

• Normal aging in rats leads to cognitive decline, particularly in learning and memory.
• Aging rats exhibit impaired spatial memory, making them a valuable model for therapeutic interventions.
• Insulin-like growth factor-I (IGF-I) is known to enhance spatial memory in aged rodents, but its effects on the hippocampal transcriptome are unstudied.

Purpose of the Study:

• To investigate the impact of IGF-I gene therapy on spatial memory performance in aged female rats.
• To analyze the changes in the hippocampal transcriptome following IGF-I gene therapy in old rats.

Main Methods:

• Aged female rats received intracerebroventricular injections of an adenovector expressing rat IGF-I or a placebo adenovector.
• Spatial memory was assessed using the Barnes maze test.
• Hippocampal RNA sequencing was performed to compare gene expression profiles between treatment groups.

Main Results:

• IGF-I treated rats demonstrated significantly improved spatial memory, evidenced by increased exploratory frequency of the goal hole.
• Hippocampal RNA sequencing identified 219 differentially expressed genes (81 downregulated, 138 upregulated) in IGF-I treated rats compared to controls.
• A subset of these genes was identified as functionally relevant to hippocampal IGF-I expression, synaptic plasticity, and neuronal function.

Conclusions:

• IGF-I gene therapy effectively enhances spatial memory in aging rats.
• This study provides the first comprehensive analysis of IGF-I's effects on the aging rat hippocampus transcriptome.
• The findings offer insights into the molecular pathways mediating IGF-I's neuroprotective effects in the aging brain.