The effect of pressure therapy on the formation of hypertrophic scar and TGF-β1/Smad signaling pathway
10.3760/cma.j.cn114453-20220215-00038
- VernacularTitle:压力对增生性瘢痕形成及TGF-β1/Smad信号通路的影响
- Author:
Peng CAO
1
;
Yunwei WANG
;
Ming YAO
;
Shaohui LI
;
Yang CHEN
;
Chan ZHU
;
Qian LENG
;
Liying REN
;
Hao GUAN
Author Information
1. 宁夏医科大学总医院烧伤整形美容科，银川 750004
- Keywords:
Cicatrix;
Pressure therapy;
Hypertrophic scar;
Transforming growth factor beta1;
Smad3 protein;
Signaling pathway
- From:
Chinese Journal of Plastic Surgery
2022;38(7):804-813
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To observe the effect of pressure therapy on the formation of hypertrophic scars(HTS) and transforming growth factor beta 1 (TGF-β1) / Sma and Mad homolog proteins (Smad) signaling pathway.Methods:Twelve adult healthy New Zealand white rabbits(provided by the Animal Experiment Center of the Air Force Military Medical University) were wounded with 1 cm round punch on 4 sites of the ventral side of each ear. Round scalpels were used to make incisions along the marked lines, dissect the skin and perichondrium. The remaining tissue was scraped off to expose the wound surface. Scar formation was observed on the 28th day after surgery. After the establishment of rabbit ear HTS models, the right ears were used as self-controls, while the left ears were set as the experimental group. Two hypertrophic scars were randomly selected from each rabbit ear, 24 per group. Experimental group: 4-0 nylon silk thread was used to sew the pressure pad on the circular NdFeB magnets pad with a diameter of 1.5 cm to the rabbit ear cartilage. Flexiforce pressure sensor was used to measure the pressure, and the pads were adjusted to maintain a pressure of 20-25 mmHg (1 mmHg=0.133 kPa) for more than 23 h per day. Control group: no treatment. On the 40th day of pressure therapy, the general morphology of rabbit ear scars were observed, and the tissues were harvested for hematoxylin and eosin (HE) staining and Masson’s Trichrome staining for histological study. The scar elevation index (SEI), the number of fibroblasts, and the thickness of the stratum corneum were calculated. The relative mRNA expression levels of TGF-β1, Smad3, collagen type (Collagen )Ⅰ, Collagen Ⅲ, α-smooth muscle actin (α-SMA) were measured with qPCR; Western blotting was used to detect the relative protein expression levels of TGF-β1, Collagen Ⅰ, Collagen Ⅲ, α-SMA and the phosphorylation level of Smad3 (the ratio of p-Smad3 and Smad3 proteins). Statistical analysis was performed with Excel 2019 and GraphPad Prism 8.0. The measurement data conformed to normal distribution and was expressed as Mean±SD. Student’s t-test was used for the comparison between two groups. P<0.05 was considered statistically significant. Results:A total of 96 wounds were formed in 12 rabbits, 27 wounds had no obvious hyperplasia, and the remaining 69 wounds formed hypertrophic scar tissue blocks with a prominent skin surface, firm texture, and dark red appearance. The scars formation rate was 71.9% (69/96). On the 40th day after the application of pressure, the scars in the experimental group were significantly reduced, softer, and the color was slightly lighter compared with the control group. The results of HE staining and Masson’s Trichrome staining showed that the thickness of the stratum corneum, SEI, and the number of fibroblasts were (69.33±6.03) μm, 1.30±0.08, and (236.30±14.64) cells/field, respectively, which were significantly lower than those in the control group [(114.00±10.15) μm, 1.72±0.05, (320.30±14.57) cells/field] (all P<0.01). Abundance in capillaries, inflammatory cells, and fibroblasts were not observed in the dermal layer. The collagen fibers were orderly arranged and sparse. The results of fluorescence quantitative PCR showed that the relative expression levels of TGF-β1, Smad3, Collagen Ⅰ, Collagen Ⅲ, and α-SMA mRNA in the experimental group were 0.48±0.08, 0.58±0.05, 0.04±0.01, 0.15±0.02, 0.31±0.03, respectively, lower than those of the control group(1.00±0.07, 1.00±0.05, 1.00±0.08, 1.00±0.10, 1.00±0.06) (all P<0.01). The results of Western blotting showed that the relative protein expression of TGF-β1, Collagen Ⅰ, Collagen Ⅲ, α-SMA and the phosphorylation level of Smad3 in the experimental group were 0.65±0.03, 0.07±0.01, 0.43±0.03, 0.53±0.03, 0.54±0.03, all lower than the control group’s 1.02±0.06, 0.93±0.05, 0.92±0.03, 0.82±0.03, 0.92±0.03 (all P<0.01). Conclusions:Pressure therapy can significantly inhibit the hyperplasia of scars, improve the structure of HTS tissue, facilitate the normal arrangement of collagen fiber, and reduce the excessive deposition of collagen. Pressure therapy may inhibit scar proliferation by regulating the TGF-β1/Smad signaling pathway.
