Increased dietary cholesterol enhances cold tolerance in Drosophila melanogaster

For many years, non-freezing cold shock injury has been associated with damage to the cell membrane. In this study, we enhanced membrane cholesterol levels of Drosophila melanogaster by raising larvae on a cholesterol-augmented diet. Diet augmentation significantly increased the amount of cholesterol in the cell membranes of the adult flies (1.57 ± 0.17 nmol mg⁻¹ vs. 0.93 ± 0.11 nmol mg⁻¹). Flies on the cholesterol-augmented diet exhibited a greater intrinsic cold tolerance: this group had a higher survival rate after a 2-h cold shock of −5°C than did the control group (71.0 ± 6.6% vs. 36.0 ± 8.1%). Cholesterolaugmented flies also had a significantly greater capacity to rapidly cold-harden to −7°C (36.7 ± 4.4%) compared to flies on a control diet (20.0 ± 2.9%). These results suggest a mechanistic link between protection from chilling or cold shock injury and modifications to the cellular membrane.