Fluoxetine effects on mitochondrial ultrastructure of right ventricle in rats exposed to cold stress.

OBJECTIVE

To assess fluoxetine effects on mitochondrial structure of the right ventricle in rats exposed to cold stress.

METHODS

The experimental study procedures were performed in 250-300g male EPM-Wistar rats. Rats (n=40) were divided into four groups: 1) Control group (CON); 2) Fluoxetine (FLU); 3) Induced hypothermia (IH) and; 4) Induced hypothermia treated with fluoxetine (IHF). Animals of FLU group were treated by the administration of gavages containing 0.75 mg/kg/day fluoxetine during 40 days. The induced hypothermia was obtained by maintaining the groups 3 and 4 in a freezer at -8 degrees C for 4 hours. The animals were sacrificed and fragments of the right ventricle (RV) were removed and processed prior to performing electron microscopic analysis.

RESULTS

The ultrastructural changes in cardiomyocytes were quantified through the number of mitochondrial cristae pattern (cristolysis). The CON (3.85%), FLU (4.47%) and IHF (8.4%) groups showed a normal cellular structure aspect with preserved cardiomyocytes cytoarchitecture and continuous sarcoplasmic membrane integrity. On the other hand, the IH (34.4%) group showed mitochondrial edema and lysis in cristae.

CONCLUSION

The ultrastructural analysis revealed that fluoxetine strongly prevents mitochondrial cristolysis in rat heart, suggesting a protector effect under cold stress condition.