Objective

2

To explore the possible mechanism of

Pizhan Powder

（皮粘散） in the treatment of chronic skin ulcer and the formula composition significance.

Methods

2

Twenty-four SD rats were randomly divided into model group，

Pizhan Powder

group，buffalo skin group， and borax group， with six rats in each group. The rat model of chronic skin ulcer was made by smear of glacial acetic acid on defective wounds. After modeling， 0.2 g of corresponding medicinal powder was given to the wounds in the

Pizhan Powder

group， the buffalo skin group and the borax group， respectively， while the model group was not treated， and the dressing was changed once a day for 21 consecutive days. Before treatment and on the 7th， 14th， and 21st day of medication， the skin ulcer wound area， ulcer color， ulcer secretion and granulation tissue of rats were recorded， and the healing rate was calculated. On the next day of last treatment， hematoxylin and eosin （HE） staining was used to observe the full-thickness pathological changes of skin tissue， and immunofluorescence was used to detect the expression of platelet-endothelial cell adhesion molecule （CD31） and type Ⅲ collagen （Collagen Ⅲ） in local ulcer tissue of rats； the mRNA expression of Wnt/β-catenin signaling pathway related genes in skin ulcer wound tissue of rats， including Wnt family protein 4 （Wnt4）， catenin β1 （Ctnnb1）， G1/S-specific cyclin-D1 （cyclin-D1）， and neural cadherin （Cdh2） were detected by real-time fluorescence quantitative （RT-qPCR）.

Results

2

Compared to those measured at the previous timepoint in the same group， the ulcer wound area and the main symptom scores of skin ulcers in the

Pizhan Powder

group， buffalo skin group and borax group significantly decreased on the 7th， 14th and 21st day， and the healing rate significantly increased on the 14th and 21st day （

P

＜0.05）. Compared to those in the model group measured at the same timepoint， the ulcer wound area and the main symptom scores of skin ulcers on the 7th， 14th and 21st day in the

Pizhan Powder

group significantly decreased， while the healing rate increases （

P

＜0.05）. Immunofluorescence showed strong fluorescence signals of CD31 and Collagen Ⅲ with good alignment on the 21st day in the

Pizhan Powder

group； HE staining showed that collagen fibers were more closely arranged， and inflammatory cell infiltration was significantly reduced， with formulation of a large amount of new capillaries； the mRNA expressions of Wnt4， Ctnnb1， Ccnd1 and Cdh2 significantly increased （

P

＜0.05）. Compared to those in the

Pizhan Powder

group measured at the same timepoint， the ulcer area of buffalo skin group and borax group on the 7th， 14th， and 21st day significantly increased， and the healing rate significantly decreased （

P

＜0.05）； the color score and granulation tissue score of ulcers in the borax group significantly increased on the 7th， 14th， and 21st day， and the ulcer secretion score on the 14th and 21st day increased （

P

＜0.05）. HE staining showed that the infiltration of inflammatory cells in the buffalo skin group and the borax group significantly increased compared to that in the

Pizhan Powder

group， and more increases were seen in the borax group. Immunofluorescence showed weak fluorescence signals of CD31 and Collagen Ⅲ in the borax group than the buffalo skin group； and mRNA expressions of Wnt4， Ctnnb1， Ccnd1 and Cdh2 significantly decreased in the borax group than the

Pizhan Powder

group （

P

＜0.05）.

Conclusion

2

Pizhan Powder

has a good therapeutic effect on chronic skin ulcer wound of rats， and the combination of buffalo skin and borax has a coordination effect. The mechanism of action may be related to the up-regulation of the expression of CD31 and Collagen Ⅲ in wound tissues by regulating the Wnt/β-catenin signaling pathway.