Hypothermia induces micronuclei in mouse bone marrow cells

Area of Science:

• Toxicology
• Genetics
• Cell Biology

Background:

• Reserpine is used to induce hypothermia in animal models.
• Hypothermia's effect on genotoxicity, specifically micronucleus induction, requires further investigation.
• Previous in vitro studies showed reserpine did not induce chromosome aberrations.

Purpose of the Study:

• To investigate the genotoxic effects of reserpine-induced hypothermia.
• To determine if low body temperature is the primary cause of micronucleus induction.
• To explore potential mechanisms of hypothermia-induced genotoxicity.

Main Methods:

• Mice were administered varying doses of reserpine to induce hypothermia.
• Rectal temperatures were monitored post-administration.
• Micronucleated polychromatic erythrocyte frequencies were analyzed in bone marrow cells.
• Controlled environmental temperature experiments were conducted to maintain normal body temperature.

Main Results:

• Reserpine induced hypothermia (rectal temperature < 33.3°C) at doses of 10-1000 mg/kg.
• Significant increases in micronucleated erythrocytes were observed at these doses (p < 0.01).
• Maintaining normal body temperature prevented micronucleus induction, even with reserpine administration.
• Approximately 50% of induced micronuclei were relatively large.

Conclusions:

• Prolonged hypothermia (below 33°C for 40 hours) induces micronuclei in mouse bone marrow cells.
• The genotoxic effect appears to be directly related to low body temperature, not reserpine itself.
• Disturbance of the mitotic apparatus is a potential mechanism for hypothermia-induced genotoxicity.