Effects of different concentrations of human umbilical cord mesenchymal stem cells to ameliorate psoriasis-like skin lesions in BALB/c mice

BACKGROUND: Psoriasis is an immune-mediated chronic, recurrent, inflammatory skin disease. In view of the research on the relationship between stem cells and the pathogenesis of psoriasis, stem cells may be a new breakthrough in the systemic treatment of psoriasis. METHODS: The BALB/c mouse psoriasis-like model induced by imiquimod was established and animals were randomly divided into a control group, model group, human umbilical cord mesenchymal stem cells (hUC-MSCs) group with different concentrations (injected separately with umbilical cord stem cells 1×10(7)/kg, 2×10(7)/kg, 4×10(7)/kg through the caudal vein) and fresh hUC-MSCs group (injected with fresh umbilical cord stem cells 2×10(7)/kg through the tail vein). The Psoriasis Area and Severity Index (PASI) score was used to observe the changes in skin lesions. The epidermal thickness, degree of keratinization and infiltration of inflammatory cells were observed by HE staining. The concentrations of TNF-α, IFN-γ, IL-17A, IL-23 and other cytokines in serum and skin of mice were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Mice treated with hUC-MSCs showed a good dose-response dependence compared with the control group. As the concentration of hUC-MSCs increased, so did the spleen index. According to the PASI integral trend chart, hUC-MSCs can delay the appearance of skin lesions and accelerate the recovery of skin lesions. HE staining showed that the number of parakeratosis cells in the hUC-MSCs treatment group was significantly decreased, and the degree of dermal hyperplasia and inflammatory cell infiltration in erythrocyte extravasation was significantly lower than in the model group. The higher the concentration of hUC-MSCs, the lower the concentration of the four cytokines in serum and skin tissue. CONCLUSIONS: hUC-MSCs had an obvious therapeutic effect on imiquimod-induced psoriasis in mice, and a high concentration of hUC-MSCs had the best therapeutic effect. This effect intensity is dose-dependent, and hUC-MSCs at high concentrations have better therapeutic effect.