(A) Drosophila flies were reared aboard the ISS in a customized Nanoracks vented fly box (VFB) containing 15 vials of flies and food (bottom, left). Each vial contained 10 virgin females and 5 males when launched. Vials remained in the VFB for the duration of the microgravity exposure.
(B) End-diastolic diameters (EDDs) in hearts from females (red, top) and males (blue, bottom) were significantly decreased in female, but not male, space flown (SF) Canton-S flies compared with ground controls (GCs). EDDs recovered in hearts from female flies born in space but cultured as adults in 1g (space flight recovery [SFR]). EDDs in all sei/hERG mutant flies were reduced relative to Canton-S flies; genetic background controls were not significantly affected by microgravity.
(C) End systolic diameters (ESDs) were also reduced in sei/hERG/hERG mutant flies under both gravity conditions relative to Canton-S flies.
(D and E) Fractional shortening (D), a measure of contractility, and cardiac output (E) were significantly reduced in hearts from both male and female Canton-S flies under microgravity and showed partial recovery in flies born in space and reared as adults in 1g (SFR). Heart function parameters were analyzed using a two-way ANOVA with Tukey’s multiple comparison post hoc test. p values are shown. Fly numbers are indicated in the bars in (B).