To discuss the effects of osthol (Ost) on melanocyte loss in vitiligo mice by regulating the Wnt/β-catenin signaling pathway.

A mouse model of vitiligo was established by applying hydroquinone cream. The successfully modeled mice were divided into model group (only modeling), low-dose experimental group (15 mg·kg^-1 Ost), high-dose experimental group (45 mg·kg^-1 Ost), positive control group (50.4 mg·mL^-1 vitiligo capsules) and inhibitor group (45 mg·kg^-1 Ost + 10 mg·kg^-1 XAV939). The control group was given an equal volume of normal saline. Each group consisted of 10 mice. After the intervention, the degree of skin depigmentation in the treatment area was scored; orbital blood was collected, and the levels of malondialdehyde (MDA), α-melanocyte-stimulating hormone (α-MSH), tyrosinase (TYR) and tumor necrosis factor-α (TNF-α) in the serum were detected by enzyme-linked immunosorbent assay (ELISA); skin lesion tissues were collected, and the number of melanin-containing hair follicles and melanocytes in the basal layer were evaluated by hematoxylin-eosin (HE) and Masson staining; the positive expression levels of tyrosinase-related protein (TRP) 1 and TRP2 in the skin lesion tissues was detected by immunohistochemistry; the mRNA expression levels of tyrosinase (TYR) and microphthalmia-associated transcription factor (MITF) mRNA in the skin lesion tissues were detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction (qRT-PCR); the protein expression levels of β-catenin and phosphorylated glycogen synthase kinase-3β (p-GSK-3β)/GSK-3β in the skin lesion tissues were detected by Western blotting.

The depigmentation scores of control group, model group, low-dose experimental group, high-dose experimental group, positive control group and inhibitor group were (0±0), (4.11±0.52), (2.41±0.28), (0.77±0.09), (0.55±0.07) and (2.55±0.28) score, respectively; the levels of α-MSH were (26.53±2.84), (7.56±0.84), (12.62±1.36), (22.91±2.44), (23.51±2.48) and (13.05±1.38) μg·L^-1, respectively; the levels of MDA were (2.05±0.24), (7.94±0.85), (4.31±0.49), (2.27±0.25), (2.19±0.24) and (4.28±0.45) nmol·mg prot^-1, respectively; the levels of TNF-α were (38.52±4.02), (105.65±10.94), (68.84±7.05), (42.84±4.45), (41.85±4.37) and (70.05±7.21) ng·mL^-1, respectively; the levels of TYR were (105.62±11.14), (45.22±4.67), (65.41±6.77), (98.62±9.98), (97.65±9.89) and (66.08±6.81) μg·L^-1, respectively; the numbers of melanocytes in the basal layer were (148.62±15.08), (52.11±5.34), (68.84±6.91), (108.64±11.14), (112.08±11.44) and (70.54±7.21) cells, respectively; the numbers of melanin-containing hair follicles were (98.64±9.98), (41.52±4.31), (62.05±6.37), (95.62±9.74), (96.05±9.78) and (61.08±6.29) cells, respectively; the positive expression levels of TRP1 were 17.05±1.94, 4.62±0.77, 8.05±0.85, 14.98±1.58, 15.22±1.64 and 8.11±0.88, respectively; the positive expressions levels of TRP2 were 14.32±1.55, 3.05±0.33, 5.74±0.66, 10.42±1.15, 11.05±1.17 and 6.05±0.62, respectively; the relative expression levels of TYR mRNA were 1.09±0.12, 0.19±0.02, 0.49±0.05, 0.79±0.08, 0.88±0.09 and 0.55±0.07, respectively; the relative expression levels of MITF mRNA were 0.98±0.11, 0.24±0.03, 0.44±0.05, 0.81±0.09, 0.85±0.10 and 0.51±0.06, respectively; the relative expression levels of β-catenin were 1.25±0.13, 0.34±0.05, 0.68±0.08, 1.07±0.11, 1.11±0.12 and 0.71±0.09, respectively; the relative expression levels of p-GSK-3β/GSK-3β were 0.85±0.09, 0.22±0.03, 0.44±0.06, 0.71±0.08, 0.79±0.09 and 0.42±0.05, respectively. There were statistically significant differences between model group and control group, between low, high dose experimental group and model group, and between inhibitor group and high-dose experimental group (all P<0.05).

Ost reduces melanocyte loss in vitiligo mice by activating the Wnt/β-catenin signaling pathway.