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Uemura M1,2, Sugimoto M1, Yoshikawa Y1, Hiramatsu T1, Inoue T3, Matsuo M1
1Kobegakuin University, Department of Rehabilitation, Kobe, Japan, 2Yoshida Hospital, Department of Rehabilitation, Kobe, Japan, 3Hyogo College of Medicine, Department of Emergency, Disaster and Critical Care Medicine, Nishinomiya, Japan
Background: The electrical stimulation (ES) therapy is recommended for pressure injury healing in some guidelines and many clinical studies showed the effects of the ES on wound healings. Migration, proliferation, and differentiation from fibroblasts to myofibroblasts are important factors for pressure injury healing. Our previous studies revealed that the monophasic pulsed current of 200 µA and 2 Hz promoted the migration and proliferation of human dermal fibroblasts (HDFs). It is necessary to set proper duty cycle because total current depends on duty cycle. However, the most effective duty cycle on wound healing is not clear.
Purpose: The purpose of this study is to investigate the effect of the difference of duty cycles on differentiation of HDFs.
Methods: HDFs were electrical stimulated for 24 hours (intensity; 0 or 200 µA, frequency; 2 Hz). Duty cycles were adapted 10, 50, or 90%. The expressions of α-smooth muscle actin (SMA) and transforming growth factor (TGF)-β1 mRNAs, the crucial factors for differentiation, were examined by taqman real-time polymerase chain reaction, and cell viability is assessed by trypan blue staining. Collagen gel contraction assay was performed, and the area of collagen gels were measured before and after the ES.
Results: The expressions of α-SMA mRNA in 50% and 90% groups were significantly higher than in control and 10% groups (p 0.01) and were nearly five times as high as that in control group. The expression of TGF-β1 mRNA in 50% group was significantly higher than in control group (p 0.05). However, cell viability in 50% and 90% groups were significantly less than in control group (p 0.01). Collagen contraction rates after the ES were significantly less than before the ES in each group (in control group; p 0.05, in the ES groups; p 0.01). Compared with the control group, collagen contraction rates after the ES in the ES groups were less (control group; 78.6%±8.6, 10% group; 62.3%±6.7%, 50% group; 61.1±0.63%, 90%group; 68.1±12.9%) but there were no significantly differences.
50% pulsed current promoted the expressions of α-SMA and TGF-β1 mRNA, leading to HDF differentiation to myofibroblasts and it may accelerate healings of pressure injuries, however long duration ES could damage on the tissues.
Conclusion(s): Monophasic 50% pulsed current can promote differentiation of HDFs and accelerate pressure injury healings, however, cytotoxicity may be increased as duty cycle approaches 100% (direct current). in vivo study is needed to analyze the optimal electrical stimulation condition for wound healings.
Implications: The present study suggests that monophasic 50% pulsed current could accelerate pressure injury healings through promotion of differentiation of HDFs.
Keywords: pressure ulcer, wound healing, micro current
Funding acknowledgements: This work was supported by JSPS KAKENHI Grant Number 16K01529.
Purpose: The purpose of this study is to investigate the effect of the difference of duty cycles on differentiation of HDFs.
Methods: HDFs were electrical stimulated for 24 hours (intensity; 0 or 200 µA, frequency; 2 Hz). Duty cycles were adapted 10, 50, or 90%. The expressions of α-smooth muscle actin (SMA) and transforming growth factor (TGF)-β1 mRNAs, the crucial factors for differentiation, were examined by taqman real-time polymerase chain reaction, and cell viability is assessed by trypan blue staining. Collagen gel contraction assay was performed, and the area of collagen gels were measured before and after the ES.
Results: The expressions of α-SMA mRNA in 50% and 90% groups were significantly higher than in control and 10% groups (p 0.01) and were nearly five times as high as that in control group. The expression of TGF-β1 mRNA in 50% group was significantly higher than in control group (p 0.05). However, cell viability in 50% and 90% groups were significantly less than in control group (p 0.01). Collagen contraction rates after the ES were significantly less than before the ES in each group (in control group; p 0.05, in the ES groups; p 0.01). Compared with the control group, collagen contraction rates after the ES in the ES groups were less (control group; 78.6%±8.6, 10% group; 62.3%±6.7%, 50% group; 61.1±0.63%, 90%group; 68.1±12.9%) but there were no significantly differences.
50% pulsed current promoted the expressions of α-SMA and TGF-β1 mRNA, leading to HDF differentiation to myofibroblasts and it may accelerate healings of pressure injuries, however long duration ES could damage on the tissues.
Conclusion(s): Monophasic 50% pulsed current can promote differentiation of HDFs and accelerate pressure injury healings, however, cytotoxicity may be increased as duty cycle approaches 100% (direct current). in vivo study is needed to analyze the optimal electrical stimulation condition for wound healings.
Implications: The present study suggests that monophasic 50% pulsed current could accelerate pressure injury healings through promotion of differentiation of HDFs.
Keywords: pressure ulcer, wound healing, micro current
Funding acknowledgements: This work was supported by JSPS KAKENHI Grant Number 16K01529.
Topic: Electrophysical & isothermal agents; Older people
Ethics approval required: No
Institution: Kobe Gakuin University
Ethics committee: Kobe Gakuin Ethics Committee
Reason not required: The present study used the cells that were purchased from a distributor.
All authors, affiliations and abstracts have been published as submitted.
