Human Umbilical Cord Mesenchymal Stem Cells Combined with Pirfenidone upregulates the Expression of RGS2 in the Pulmonary Fibrosis in Mice

Abstract: Objective The therapeutic effect of umbilical cord-derived mesenchymal stem cells(hUC-MSCs) in combination with pirfenidone(PFD) on pulmonary fibrosis in mice and its possible mechanism were investigated. Methods C57BL/6 mice were randomly divided into six groups: control group, model group, P₁₀ group, P₃₀ group, P₁₀₀ group and P₃₀₀ group. Modeled by tracheal intubation with 3 mg/kg bleomycin drip, each dose of PFD was given daily by gavage from day 7 onwards. Mice were observed continuously for 21 days and survival was recorded. Lung tissues were collected on day 21, and HE and Masson staining were performed to assess morphological changes and collagen deposition in the lungs. Collagen content was measured by Sircol method, and fibrosis marker levels were detected by PCR and Western Blot. Another batch of C57BL/6 mice was then randomly divided into five groups: hUC-MSCs control group, model group, P₁₀₀ group, hUC-MSCs treatment group and hUC-MSCs + P₃₀ group. 5×10⁵ hUC-MSCs were injected into the tail vein on day 7, and the mice were given PFD gavage daily from day 7 onwards, and their survival was recorded. Lung tissues were collected on day 21 to detect pathological changes and the expression of collagen content and regulator of G protein signaling 2(RGS2). Pulmonary myofibroblasts were divided into MFB group and MFB + hUC-MSCs group, and different doses of PFD were added to each group, and the levels of RGS2 and fibrosis markers were detected in each group. Results Compared with other doses of PFD groups, the P₁₀₀ group significantly improved mouse survival and lung pathology, and significantly reduced collagen and fibrosis marker levels (p < 0.05). The hUC-MSCs + P₃₀ group significantly improved mouse survival and lung pathology, significantly reduced collagen and fibrosis marker levels (p < 0.05), and the efficacy was better than that of the P₁₀₀ and hUC-MSCs groups (p < 0.05). RGS2 expression was significantly higher in the MSCs + P₃₀ group compared with the P₁₀₀ and hUC-MSCs groups (p < 0.05). PFD increased RGS2 expression in MFB (p < 0.05) in a dose-dependent manner. Fibrosis markers were more significantly reduced in the hUC-MSCs + PFD relative to the PFD alone group and the hUC-MSCs group. Conclusion The study suggested that hUC-MSCs combined with low-dose PFD showed a therapeutic effect better than that of the two treatments used separately. Its effect attenuating bleomycin-induced pulmonary fibrosis in mice is related with the increase of RGS2.