Changes in the Cardiotoxic Effects of Lead Intoxication in Rats Induced by Muscular Exercise

Figure 1. Superposition of the force development time course for steady-state isometric contractions of right ventricular trabecules (A) and papillary muscles (B) from male rats of the control group and the three exposed groups (here and in the following figures, designations are given in the legend, and the number of preparations is given in brackets). Force is given in units normalized to amplitude. Muscle length is 95% Lmax.

Figure 2. The relationships between passive tension amplitude and relative muscle length of trabecules (A) and papillary muscles (B) in the experimental groups. The number of preparations is given in brackets. Muscle length is shown in Lmax units. Data are shown as mean ± S.D. There are significant differences (by Mann–Whitney U-test): *—“Running” vs. “Control”; +—“Pb” vs. “Control”; #—“Pb + Running” vs. “Control”; □—“Pb + Running” vs. “Pb”.

Figure 3. The relationships between active tension amplitude and relative muscle length of trabecules (A) and papillary muscles (B) in the experimental groups. The number of preparations is given in brackets. Muscle length is shown in Lmax units. Data are presented as mean ± S.D. There are significant differences (by Mann–Whitney U-test): +—“Pb” vs. “Control”.

Figure 4. The relationships between maximal normalized rate and relative muscle length of trabecules (A) and papillary muscles (B) in the experimental groups. The number of preparations is given in brackets. Muscle length is shown in Lmax units. Data are presented as mean ± S.D. There are significant differences (by Mann–Whitney U-test): #—Pb + “Running“ vs. “Control”; ●—“Pb + Running” vs. “Running”; ○—“Pb” vs. “Running”.

Figure 5. The relationships between normalized rate of force relaxation and relative muscle length of trabecules (A) and papillary muscles (B) in the experimental groups. The number of preparations is given in brackets. Muscle length is shown in Lmax units. Data are presented as mean ± S.D. There are significant differences (by Mann–Whitney U-test): *—“Running” vs. “Control”; +—“Pb” vs. “Control”; #—“Pb + Running” vs. “Control”; ●—“Pb + Running” vs. “Running”; ○—“Pb” vs. “Running”.

Figure 6. Isometric contraction time parameters of trabecules (A,C) and papillary muscles (B,D) in the experimental groups. The number of preparations is given in brackets. Muscle length is shown in Lmax units. Data are presented as mean ± S.D. There are significant differences (by Mann–Whitney U-test): +—“Pb” vs. “Control”; #—“Pb + Running” vs. “Control”; ●—“Pb + Running” vs. “Running”; ○—“Pb” vs. “Running”.

Figure 7. The force–velocity relationships of trabecules (A) and papillary muscles (B) in the experimental groups. Velocity is shown in relative units according to a muscle’s working length. The number of preparations is given in brackets. Data are presented as mean ± S.D. There are significant differences (by Mann–Whitney U-test): +—“Pb” vs. “Control”; ●—“Pb + Running” vs. “Running”; □—“Pb + Running” vs. “Pb”; ○—“Pb” vs. “Running”.

Figure 8. The end-systolic length–afterload relationships of trabecules (A) and papillary muscles (B) in the experimental groups. The number of preparations is given in brackets. Data are presented as mean ± S.D. There are significant differences (by Mann–Whitney U-test): *—“Running” vs. “Control”; +— “Pb” vs. “Control”; #—“Pb + Running” vs. “Control”; □—“Pb + Running” vs. “Pb”; ○—“Pb” vs. “Running”.

Figure 9. The work–afterload relationships of trabecules (A) and papillary muscles (B) in the experimental groups. The number of preparations is given in brackets. Data are presented as mean ± S.D.

Figure 10. Representative examples of electropherograms showing the ratio of α- and β-MHC extracted from the RV rat myocardium. Left to right: “Control”; “Pb”; “Running”; “Pb + Running”.

Figure 11. Variability of combined action of running and lead intoxication on (A) total Ca (from additive action towards subadditivity) and (B) VEGF (from single-factor action of exercise, through synergism, to additivity) in blood serum. Regression equations are y=2.543−0.155x1−0.136x2−0.165x1x2 for (A) and y=6.046−0.912x1+2.332x2+5.120x1x2 for (B).

Figure 12. Variability of combined action of running and lead intoxication on (A) isoline amplitude (2 lead, opposite action), (B) amplitude T (2 lead, complicated picture: from subadditive action at low doses of lead and exercise, through antagonism, to synergism at high doses), (C) inspiratory time (complicated picture: same as in (B)). Regression equations are y=−0.063−0.007x1+0.002x2+0.006x1x2 for (A), y=0.127+0.019x1+0.013x2−0.028x1x2 for (B) and y=202.7−14.283x1−22.568x2+35.570x1x2 for (C).