Name: SAMYA MERE LIMA RODRIGUES
Publication date: 06/05/2019
Advisor:
Name |
Role |
|---|---|
| EDUARDO HERTEL RIBEIRO | Co-advisor * |
| IVANITA STEFANON | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ALESSANDRA SIMAO PADILHA | Internal Examiner * |
| AURÉLIA ARAÚJO FERNANDES | External Examiner * |
| EDUARDO HERTEL RIBEIRO | Co advisor * |
| IVANITA STEFANON | Advisor * |
| NAZARE SOUZA BISSOLI | Internal Examiner * |
Summary: This study aimed to identify if the production of reactive oxygen species by NADPH oxidase and mitochondria trigger the dysfunction in this model of female sex hormone deprivation for 60 days. Wistar rats with ≈7 weeks old and randomly divided into 4 groups: Sham, Ovx, Ovx + Apocynin (Ovx + Apo) and Ovx + Spironolactone (Ovx + Spiro). The results showed that Apo was able to prevent body weight gain in the animals. Spiro was unable to prevent body weight gain. Evaluating myocardial contractility, we observed that
Apo treatment was able to prevent the reduction of myocardial contractility observed in Ovx animals (Sham: 605.4 ± 10.37 g - Ovx: 358.3 ± 21.23 * g / Ovx + Apo (dF / dt +: Sham mg vs. Ovx * mg / Ovx + Apo # mg / mg p <0.01) and ( dF / dt-Sham mg vs. Ovx * mg / Ovx + Apo # mg / mg, p <0.01); and the treatment with Spiro also presented preventive
capacity (Sham: 712 ± 14.31 g - Ovx: 281.3 ± 7.99 * g / Ovx + Spiro: 726.1 ± 4.39 # g / g, p <0.01). All groups showed positive inotropic strength in response to Ca 2+ and Isoproterenol, but the Ovx groups treated with Apo and / or Spiro presented similar responses to the Sham group and in the Ovx group such responses were reduced (Ca2+-1.25-Sham: 484 ± 20.52 g vs Ovx: 247 ± 12.23 * g vs. Ovx + Apo: 494 ± 32.40 g / g, p<0.01) - (Ca2+- 1.25-Sham: 450.81 ± 38, 08 g vs. Ovx: 285.29 ± 23.89 * g vs Ovx + Spiro: 544.71 ± 57.06 # g / g, p <0.01). Response to the β-adrenergic agonist isoproterenol in the Ovx group treated with Apo was similar to the Sham group and the untreated Ovx animals showed reduction in the contractile response (Iso Log [M] 10-3-Sham: 592.73 ± 26.59 gOvx: 345.43 * ± 31.12g / Ovx + Apo: 627.51 ± 21.44 # g / g, p <0.05). In the Ovx animals the response to Iso was reduced compared to Sham and the treatment with Spiro prevented such eduction (Iso Log [M] 10-3 -Sham: 607.19 ± 22.87 g - Ovx: 304.98 ± 28, 68
* g / Ovx + Spiro: 666.12 ± 71.24 g / g, p <0.05). Expression of Serca 2a protein was reduced, and expression of phospholabam (PLB) and Nox4 were increased in Ovx animals compared to Sham and Apo and / or Spiro treatment reversed the reduction of Serca 2a expression (Sham: 1.39 ± 0.12 - Ovx: 0.86 ± 0.05 * / Ovx + Apo: 1.26 ± 0.08 # - Ovx + Spiro: 1.28 ± 0.10 # p <0.05) and reduced PLB and Nox4 (PLB-Sham: 1.12 ± 0.06 - Ovx: 1.63 ± 0.08 * / Ovx + Apo: 0.99 ± 0.07 # - Ovx + Spiro: 1 , 0.64 ± 0.05 - Ovx: 1.22 ± 0.15 * / Ovx + Apo: 0.64 ± 0.07, - Ovx + Spiro: 0.65 ± 0.10%, p <0.05). Ovx animals had higher superoxide anion production when compared to Sham, and Apo and Spiro treatments reduced this increase (Sham: 3.85 ± 0.40 - Ovx: 9.74 ± 1.03 * / Ovx + Apo: 4.16 ± 0.48 # - Ovx + Spiro: 2.99 ± 0.21 #, p <0.01). The maximum mitochondrial respiration rate in response to the substrates (glutamate + malate: G + M, palmitoyl Lcarnitine: PC and pyruvate: P + M) of the IFM subpopulations in State 3 were reduced in the Ovx vs Sham group, and the treatments with Apo and Spiro prevented such reduction
(Ovx vs. Ovx Apo / or Spiro Ovx, p <0.05) in the SSM subpopulations in State 3 only in response to the G + M substrate the maximum respiration rate was shown reduced in the Ovx vs Sham animals and preventive treatments with Apo / Spiro reversed the reduction of the maximum respiration rate. In State 4 of the IFM and SSM subpopulations the maximal respiration rate was increased in the Ovx vs Sham groups in the presence of all substrates and the Apo / or Spiro treatments reduced this increase. A reduction in the expression of
the mitochondrial complexes I, IV and III in the Ovx subpopulation IFM was observed, and the non-reversible Apo / or Spiro treatments were able to reverse the reduction (Complex I: Sham: 0.96 ± 0.08- Ovx: 0.53 ± 0.08 / Ovx + Apo: 0.75 ± 0.11 * -Ovx + Spiro: 0.59 ± 0.08 * μg - Complex IV: Sham: 1.22 ± 0.17- Ovx: 0.80 ± 0.09 * / Ovx + Apo: 0.95 ± 0.09 * -Ovx + Spiro: 0.70 ± 0.07 * μg - Complex III: Sham: 1.19 ± 0.17 -Ovx: 0.79 ± 0.09 * / Ovx + Apo: 0.74 ± 0.09 * -Ox + Spiro: 0.73 ± 0.05 * μg, p <0.05). In the SSM subpopulation of the Ovx + Spiro group there was a reduction in the expression of Complexes I, IV and III (Complex I: Sham: 1.30 ± 0.18- Ovx: 0.99 ± 0.18 / Ovx + Apo: 1.07 ± 0.06-Ovx + Spiro: 0.93 ± 0.09 * μg, p <0.05 - Complex IV: Sham: 1.30 ± 0.20-Ovx: 0.99 ± 0.13 / Ovx + Apo: 0.86 ± 0.09 * - Ovx + Spiro: 0.79 ± 0.08 * μg, p <0.05 - Complex III: Sham: 1.33 ± 0.19-Ovx: 0.99 ± 0.12 / Ovx + Apo: 1.08 ± 0.08-Ovx + Spiro: 0.02 ± 0.07 * μg, p <0.05). Expression of the MnSOD and Catalase antioxidant proteins were reduced in the Ovx vs. Sham rats and Apo or Spiro treatments prevented the reduction of the expression of the proteins mitochondrial CTE Tfam and PGC1α were reduced Ovx vs Sham and Apo or Spiro treatments prevented
such reduction. Our results confirmed that estrogen hormone deprivation increases oxidative stress both by NADPH oxidase and mitochondria, and the preventive treatments with Apocynin and Spironolactone had antioxidant action and were able to prevent damage in myocardial contractility.
