Cardioprotective effects of triiodothyronine supplementation against ischemia reperfusion injury by preserving calcium cycling proteins in isolated rat hearts
Authors: Jian Lu
Zhiping Xu
Lichao Fang
Shigang Qiao
Lijun Liu
Lei Hong
Jianzhong An
Journal: Experimental and Therapeutic Medicine (2019)
Discipline: CLINICAL MEDICINE
Keywords: calcium cycling protein; cardiac function; high-energy phosphate; ischemic reperfusion injury; triiodothyronine.
Affiliations: Department of Emergency Medicine, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China., Intensive Care Unit, Suzhou Xiangcheng People Hospital, Suzhou, Jiangsu 215131, P.R. China., Institute of Clinical Medicine Research, The Affiliated Suzhou Science and Technology Town Hospital of Nanjing Medical University, Suzhou, Jiangsu 215153, P.R. China.

Abstract:  Hypothyroidism is associated with profound left ventricular dysfunction. Triiodothyronine (T3) supplementation may improve cardiac function after ischemic reperfusion (I/R) injury. In the present study, the effect of T3 on major calcium cycling proteins and high-energy phosphate content during I/R was evaluated. Isolated perfused rat hearts were divided into 5 groups: Sham Control (Sham, n=10), Control (n=8), T3 10 nM (T3-10, n=10), T3 25 nM (T3-25, n=10) and T3 50 nM (T3-50, n=10). T3 was administrated for 60 min before 30 min of ischemia and 120 min of reperfusion. The protein contents of Ca2+-release channels (RyR2), Ca2+-adenosine triphosphatase (SERCA2a), phospholamban (PLB), sarcolemmal Ca2+-adenosine triphosphatase (PMCA) and sodium-calcium exchanger (NCX), as well as the high-energy phosphate content in heart tissues were measured by western blot analysis. The results revealed that T3 improved the contractile recovery (left ventricular developed pressure; +dP/dt, -dP/dt) after I/R. Western blotting assays demonstrated that I/R depressed the contents of RYR2, SERCA2a and phosphorylated RYR2 and PLB; there were no effects on the contents of PLB, PMCA and NCX. T3 reversed I/R-induced degradation of RyR2 and SERCA2a, restored the phosphorylation of RyR2 and PLB, and preserved the high-energy phosphate contents of ATP and creatine phosphate. T3 supplementation protected the heart against I/R injury via the preservation of Ca2+-cycling proteins and high-energy phosphate content. 

Retracted: No

PubPeer comments:
 Figure 2A and 4A. * Red boxes: The GAPDH panel of Figure 2A (also that in 3A) looks remarkably similar to the PMCA panel in Figure 4A, albeit shown at different exposures. ![file] , 
 And what s going on here in the bottom right of figure 4A? ![file] , 
 Correction, 16 December 2020: https: www.spandidos-publications.com 10.3892 etm.2020.9581  *Subsequently to the publication of the above article, an interested reader drew to the authorsu2019 attention that the GAPDH panel of the western blots shown in Figs. 2A and 3A appeared to be remarkably similar to the PMCA data panel shown in Fig. 4A, albeit at different exposures.* *The authors have reviewed the original data, and realized that, during the preparation of the figures submitted in the original manuscript, incorrect data were selected for the PMCA data panel in Fig. 4A. Consequently, a corrected version of Fig. 4 is shown opposite, containing the correct data for the PMCA experiment.* *Note that this error did not affect the overall conclusions reported in the paper. The authors sincerely apologize for the error caused by the inadvertent selection of incorrect data in Fig. 4A, and thank the reader for drawing this error to their attention. The authors also apologize to the Editor of Experimental and Therapeutic Medicine and to the readership for any inconvenience caused.* Of note, in the corrected figure, not only the PMCA panel has been replaced, but also the GAPDH panel. Could the authors please comment on that? The Correction Notice does not mention this. ![file] , 
 #2 If we look closely, several bands in this panel showed a similar situation. It may be due to: uneven distribution of developing solution; a longer exposure time, relatively large amount of protein results in a darker background; a low image resolution; repeated application of antibodies leads to insufficient efficacy, and the glue concentration is not uniform in that part. We are not sure whether this problem is caused by one or more factors and will need to be clarified in future experiments. #3 When we corrected the error of PMCA panel, we also found the inadequacy of the GAPDH band pointed out by Dr. John A Loadsman (see above), so the original panel was replaced by another GAPDH panel, which was run by same original samples under same conditions. Your question is appreciated, and it is pity that it was not mentioned in the Corrigendum. ,