Intradermal Hypoxia MSC Secretome Modulates Filaggrin and Loricrin in SLS-Induced Xerosis-Like Wistar Rats

Background: Xerosis cutis is characterized by epidermal barrier dysfunction and reduced expression of filaggrin (FLG) and loricrin (LOR). Current management mainly relies on emollients and moisturizers that provide symptomatic relief without restoring the barrier. However, the effect of intradermal hypoxia-conditioned mesenchymal stem cell secretome (SH-MSCs) on these proteins remains unclear. This study evaluated the effect of intradermal SH-MSCs on FLG and LOR expression in a sodium lauryl sulfate (SLS)-induced xerosis-like Wistar rat model.Materials and methods: Thirty male Wistar rats were randomized and divided into 6 groups. Xerosis model was prepared with topical application of 5% SLS twice daily for 9 days. Xerosis rats were treated with NaCl/100-300 µL of SH-MSC. Skin tissue was observed and documented macroscopically and dermoscopically. In addition, skin samples were collected on day 22, mRNA was isolated, FLG and LOR mRNA expression was quantified by qPCR using the 2−ΔΔCt method relative to GAPDH.Results: SLS induced dryness, scaling, erythema, fissuring, and epidermal thickening. LOR expression differed significantly among groups (F(5, 24) = 20.629, p<0.001), with the lowest level in the xerosis and the highest in the 300 µL group. FLG expression also differed significantly (F(5, 24)=18.266, p<0.001). Both FLG and LOR were increased dose-dependently.Conclusion: Intradermal SH-MSC enhanced the expression of epidermal barrier-related genes in an SLS-induced xerosis-like rat model. Under the conditions tested, the 300 µL SH-MSC dose appeared to be the most effective for modulating both FLG and LOR expression. These findings could suggest the potential relevance of hypoxia-conditioned MSC secretome as a cell-free strategy for barrier restoration. Keywords: xerosis cutis, sodium lauryl sulfate, hypoxia-conditioned mesenchymal stem cell secretome, intradermal injection, filaggrin, loricrin