Hippocampal dysfunctions in tumor-bearing mice

Area of Science:

• Neuroscience
• Oncology
• Molecular Biology

Background:

• Cancer patients often experience depression and cognitive decline.
• The underlying mechanisms of cancer-related hippocampal dysfunction remain unclear.

Purpose of the Study:

• To investigate how peripheral tumors affect emotional behavior, memory, and hippocampal function in an animal model.
• To explore the molecular and cellular changes in the hippocampus associated with tumor presence.

Main Methods:

• Adult mice were inoculated with colon carcinoma cells (CT26) or vehicle.
• Behavioral tests (tail suspension, object recognition) were performed.
• Hippocampal neurogenesis, pro-inflammatory cytokines (IL-6, TNF-α), BDNF, COX-2, and stress markers (corticosterone) were analyzed.

Main Results:

• Tumor-bearing mice exhibited increased depression-like behavior and memory impairment.
• Elevated hippocampal IL-6 and TNF-α mRNA, plasma IL-6, and corticosterone levels were observed.
• Reduced hippocampal neurogenesis (Ki-67, doublecortin positive cells) and lower BDNF and COX-2 mRNA levels were found.

Conclusions:

• A peripheral tumor can independently cause hippocampal dysfunction, leading to behavioral and cognitive deficits.
• Reduced neurogenesis and altered molecular signaling (BDNF, COX-2), along with increased inflammation and stress, likely contribute to these effects.