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Objective:To investigate the inhibitory effect and mechanisms of action of mucopolysaccharide polysulfate cream on hypertrophic scar formation.Methods:Circular full-thickness wounds with a diameter of 6 mm were made in both ears of 16 New Zealand white rabbits to establish a rabbit ear model of hypertrophic scar. There were 3 hypertrophic scars in each rabbit ear. About 14 days after the operation, scars on the left ear were topically treated with mucopolysaccharide polysulfate cream, and served as the experimental group; scars on the right ear were topically treated with the cream vehicle, and served as vehicle control group. The dosage of topical agents for one rabbit ear was approximately 0.4 g, which were given twice a day for 6 consecutive weeks. Scar tissues were collected on days 0, 14 and 42, that is, 14, 28 and 56 after operation respectively, and subjected to hematoxylin and eosin (HE) staining, Masson staining and immunohistochemical study, so as to evaluate histopathological scores, measure the scar thickness and collagen fiber density, and determine the expression of type Ⅰ and Ⅲ collagen and the ratio of type Ⅰ/Ⅲ collagen. The t test and one-way analysis of variance were used to compare the indices between groups. Results:Compared with pretreatment histopathological manifestations, HE staining showed extensive extracellular matrix deposition, inflammatory cell infiltration and local hyperemia in the control group after 42-day treatment, but no obvious changes in the experimental group. The pathological scores of scar tissues on the rabbit ears significantly increased over time in the control group (days 0, 14 and 42: 4.16 ± 1.61, 6.50 ± 1.46, 6.53 ± 1.34, respectively; F = 13.69, P = 0.001) , while there was no significant change in the experimental group (days 0, 14 and 42: 4.65 ± 1.52, 5.13 ± 1.83, 5.38 ± 1.60, respectively; F = 0.78, P > 0.05) . Masson staining showed extremely high content of dark blue-dyed collagen fibers in the control group on day 42, but there was a decrease in the content of collagen fibers in the experimental group; with the increase in treatment duration, the thickness of scar tissues significantly increased in the control group compared with that before treatment ( F = 5.64, P = 0.007) , while there was no significant change in the experimental group ( F = 1.48, P > 0.05) . Immunohistochemical study revealed no significant change in the expression of type Ⅲ collagen in either the experimental group or the control group at any of the above posttreatment time points compared with that on day 0 ( F = 0.22, 0.92, respectively, both P > 0.05) , but the expression of type Ⅰ collagen and the ratio of type Ⅰ/Ⅲ collagen significantly increased in the control group ( F = 7.47, P < 0.001; F = 4.70, P = 0.005, respectively) . On day 42, the expression of type Ⅰ collagen and the ratio of type Ⅰ/Ⅲ collagen significantly decreased in the experimental group compared with the control group ( t = 3.04, P = 0.007; t = 2.35, P = 0.030, respectively) . Conclusion:Topical mucopolysaccharide polysulfate cream is effective in preventing and inhibiting scar hypertrophy by reducing the scar thickness and inhibiting the collagen fiber hyperplasia and type I collagen expression.
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BACKGROUND@#Systemic lupus erythematosus (SLE) is a complex autoimmune disease, and the mechanism of SLE is yet to be fully elucidated. The aim of this study was to explore the role of two-pore segment channel 2 (TPCN2) in SLE pathogenesis.@*METHODS@#Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the expression of TPCN2 in SLE. We performed a loss-of-function assay by lentiviral construct in Jurkat and THP-1 cell. Knockdown of TPCN2 were confirmed at the RNA level by qRT-PCR and protein level by Western blotting. Cell Count Kit-8 and flow cytometry were used to analyze the cell proliferation, apoptosis, and cell cycle of TPCN2-deficient cells. In addition, gene expression profile of TPCN2-deficient cells was analyzed by RNA sequencing (RNA-seq).@*RESULTS@#TPCN2 knockdown with short hairpin RNA (shRNA)-mediated lentiviruses inhibited cell proliferation, and induced apoptosis and cell-cycle arrest of G2/M phase in both Jurkat and THP-1 cells. We analyzed the transcriptome of knockdown-TPCN2-Jurkat cells, and screened the differential genes, which were enriched for the G2/M checkpoint, complement, and interleukin-6-Janus kinase-signal transducer and activator of transcription pathways, as well as changes in levels of forkhead box O, phosphatidylinositol 3-kinase/protein kinase B/mechanistic target of rapamycin, and T cell receptor pathways; moreover, TPCN2 significantly influenced cellular processes and biological regulation.@*CONCLUSION@#TPCN2 might be a potential protective factor against SLE.