Low-Level Laser Therapy Decreases Renal Interstitial Fibrosis
Abstract
Objective: the purpose of this study was to investigate the effect of low-level laser therapy (LLLT) on chronic kidney disease (CKD) in a model of unilateral ureteral obstruction (UUO).
Background data: Regardless of the etiology, CKD involves progressive widespread tissue fibrosis, tubular atrophy, and loss of kidney function. This process also occurs in kidney allograft. At present, effective therapies for this condition are lacking. We investigated the effects of LLLT on the interstitial fibrosis that occurs after experimental UUO in rats.
Methods: The occluded kidney of half of the 32 Wistar rats that underwent UUO received a single intraoperative dose of LLLT (AlGaAs laser, 780 nm, 22.5 J/cm2, 30 mW, 0.75 W/cm2, 30 sec on each of nine points). After 14 days, renal fibrosis was assessed by Sirius red staining under polarized light. Immunohistochemical analyses quantitated the renal tissue cells that expressed fibroblast (FSP-1) and myofibroblast (α-SMA) markers. Reverse transcriptase polymerase chain reaction (RT-PCR) was performed to determine the mRNA expression of interleukin (IL)-6, monocyte chemotactic protein-1 (MCP-1), transforming growth factor (TGF)-β1 and Smad3.
Results: The UUO and LLLT animals had less fibrosis than the UUO animals, as well having decreased expression inflammatory and pro-fibrotic markers.
Conclusions: For the first time, we showed that LLLT had a protective effect regarding renal interstitial fibrosis. It is conceivable that by attenuating inflammation, LLLT can prevent tubular activation and transdifferentiation, which are the two processes that mainly drive the renal fibrosis of the UUO model.
Jitao Yang, MM,1 Zhenfeng Huang, MM,1 Yuyang Zhou, MM,1 Shunping Sai, BSc,2 Fangtao Zhu, MM,1 Ruitao Lv, MM,1 and Xian’en Fa, MD1
Abstract
Objective: The purpose of this study was to assess the effects of low-level laser irradiation (LLLI) on the expression of oxygen free radicals (OFR) and ventricular remodeling (VR) in the model of rat myocardial infarction (RMMI). Background data: LLLI reduces the infarct size and formation of scar tissue in the rat heart after myocardial infarction (MI). However, the exact mechanism has not been demonstrated so far. Methods: RMMI was induced by ligating the left anterior descending coronary artery (LAD). After 3 weeks, LLLI (635 nm, 6mW laser, 7.64mW/cm2, 125 sec, 0.96 J/cm2) was applied to the surface of heart directly. Four to six rats were euthanized at 1 h, 24 h, 48 h, 72 h, and 1 week after LLLI, and the infarcted myocardia were excised for the measurement of the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA). At the end of 4 weeks after MI, the hearts were harvested for histological analysis.
Results: Myocardial SOD activity with LLLI was lower compared with control ( p < 0.05), and myocardial MDA content with LLLI was higher compared with control ( p < 0.05), at all the time points. In all rats, the activity of SOD was down to the minimum and the content of MDA was up to the peak at 48 h after laser irradiation. The infarct size was reduced (35 – 10% vs. 18 – 9%, p < 0.05), the left ventricular wall thickness was increased (0.31 – 0.03 vs. 0.84 – 0.02mm, p < 0.05) and the percentage of collagen fibers in the infarcted area was attenuated (64.34 – 2.20% vs. 30.97 – 2.60%) by LLLI.
Photomedicine and Laser Surgery Volume 30, Number 12, 2012
Low-Level Laser Therapy Decreases Renal Interstitial FibrosisFabiana Aparecida Mayrink Oliveira, M.D.,1,2 Ana Carolina Meneghin Moraes, M.D.,1,2 Amanda Povoa Paiva, M.D.,1,2 VaÃ�â€&xnbsp; nia Schinzel, M.D.,1,2 Matheus Correa-Costa, Ph.D.,3,4 Patricia Semedo, Ph.D.,4 AngeÃ�â€&xnbsp; la Castoldi, B.S., M.Sc.,4 Marcos Antonio Cenedeze,4 Roberto Sotto-Maior Fortes Oliveira, Ph.D.,2 Marcus Gomes Bastos, M.D., Ph.D.,1 Niels Olsen Saraiva CaÃ�â€&xnbsp; mara, M.D., Ph.D.,3,4 and Helady Sanders-Pinheiro, M.D., Ph.D.1ââ�¬â€�4
Objective: The purpose of this study was to investigate the effect of low-level laser therapy (LLLT) on chronic kidney disease (CKD) in a model of unilateral ureteral obstruction (UUO).
Background Data:Regardless of the etiology, CKD involves progressive widespread tissue fibrosis, tubular atrophy, and loss of kidney function. This process also occurs in kidney allograft. At present, effective therapies for this condition are lacking. We investigated the effects of LLLT on the interstitial fibrosis that occurs after experimental UUO in rats.
Methods: The occluded kidney of half of the 32 Wistar rats that underwent UUO received a single intraoperative dose of LLLT (AlGaAs laser, 780 nm, 22.5 J/cm2, 30mW, 0.75W/cm2, 30 sec on each of nine points). After 14 days, renal fibrosis was assessed by Sirius red staining under polarized light. Immunohistochemical analyses quantitated the renal tissue cells that expressed fibroblast (FSP-1) and myofibroblast (a-SMA) markers. Reverse transcriptase polymerase chain reaction (RT-PCR) was performed to determine the mRNA expression of interleukin (IL)-6, monocyte chemotactic protein-1 (MCP-1), transforming growth factor (TGF)-b1 and Smad3.
Results: The UUO and LLLT animals had less fibrosis than the UUO animals, as well having decreased expression inflammatory and pro-fibrotic markers.
Conclusion: For the first time, we showed that LLLT had a protective effect regarding renal interstitial fibrosis. It is conceivable that by attenuating inflammation, LLLT can prevent tubular activation and transdifferentiation, which are the two processes that mainly drive the renal fibrosis of the UUO model.
