Effects of Photobiomodulation in Mrna Expression of Extracellular Matrix Components of Cardiac Fibrosis in Experimental Post‐infarcted Myocardial in Rats

IntroductionMyocardial infarction (MI) is due to irreversible cell death (necrosis) of the heart muscle, secondary to a prolonged inhibition of oxygen supply (ischemia). Fibrosis is the major histologic marker, resulting in heart failure from myocardial infarction. Recently, low intensity laser (LBI) has become an alternative therapy to modulate various biological processes and depending on the wavelength, dosage and condition of the irradiated tissue, has anti‐inflammatory effect, reduces pain and speeds up cell proliferation.ObjectiveTo evaluate the effect of photobiomodulation on genes involved in the formation of post‐MI cardiac fibrosis by analyzing the mRNA of Col1a1, Col3a1, MMP‐1, MMP‐2, MMP‐9 and TIMP‐1 and TIMP‐2.Materials and MethodsFifteen female Wistar rats were divided into three groups: Sham (5), IM (5) and IM + Laser (5) (Ethics Committee: 0015–2012). The infarction induction was made by occlusion of the descending left coronary artery, the laser being applied for 60 seconds at the occlusion site immediately after the infarction. Left ventricle samples from the experimental animals were collected 72h after infarction. Modifications in gene expression of genes: Edn1, Ace, Agtr1a and Ace2 were analyzed by Real‐Time PCR.ResultsThere was a significant increase in the expression of Col1a1 and Col3a1 in 1270.0% and 605.0%, respectively, in the IM group compared to the SHAM group. In contrast, the expression of Col1a1 and Col3a1 was decreased by 51.68 %% and 42.70%, respectively, in the IM + Laser group, when compared to the IM group. There was a significant increase in the expression of MMP‐1, MMP‐2 and MMP‐9 by 240%, 166% and 295%, respectively, in the IM group compared to the SHAM group. Photobiomodulation was able to reduce the expression of all genes mentioned above in 64.12%, 62.78 and 76.71% respectively. We also observed a reduction in TIMP‐1 and TIMP‐2 mRNA expression in 32% and 35%, respectively, in the IM group compared to the SHAM group.ConclusionPhotobiomodulation was able to reduce the expression of COL1A1 and COL3A1 in the IM + Laser group when compared to the IM group, and also related to the reduction of MMPs expression and increase of TIMP‐1 and TIMP‐2 inhibitors, demonstrating the effects of laser therapy in reducing collagen deposition.Support or Funding InformationFAPESP, CNPq, CAPES, UNINOVEThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.