Fig. 3

Lowered heart rate, ventricular dimensions, stroke volume and cardiac output in zebrafish embryos treated with cigarette smoke or snuff extracts. (A) Still images from a microscope video of a zebrafish larvae at 3days post-fertilization (dpf). The area indicated by a red box in the image to the left is enlarged and shown at end systole or end diastole in the middle or right images, respectively. A, Atrium; r_l, long-axis radius; r_s, short-axis radius; V, volume. (B,C) Quantification of the average volume of the ventricle at systole (B) or diastole (C) in 3dpf embryos treated with nothing, cigarette smoke extract at 1:30 dilution (CS), snuff extract at 1:50 dilution (Sn) or the anesthetic tricaine (Tri) at 0.2mg/ml. n=10, 3, 9 and 5 embryos (three measurements per embryo) in the control, CS, SN and Tri groups respectively. *P<0.05, ***P<0.001. (D) Quantification of the stroke volume in picoliters (pl) of the same 3dpf embryos as in B and C. **P<0.01, ***P<0.001. (E) Quantification of the average heart rate in beats per minute (beats/min) of the same 3dpf embryos as in B and C. **P<0.01, ***P<0.001. (F) Quantification of the cardiac output in nanoliters per minute (nl/min) of the same 3dpf embryos as in B and C. **P<0.01, ***P<0.001. The experiment was repeated with similar results. Results are shown as means±s.e.m. and statistical evaluation was done using Student’s two-tailed t-test assuming equal variance between the groups.