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ABSTRACT
Methods A total of 30 nasal primary pterygium tissues from patients who underwent pterygium excision surgery and 30 nasal normal conjunctival tissues from patients who underwent strabismus correction surgery were collected from the First Affiliated Hospital of Harbin Medical University between January 2022 and March 2023, serving as the pterygium group and normal control group, respectively.LRG1 protein expression in both groups was detected by immunofluorescence staining.The mRNA and protein levels of LRG1 and transforming growth factor-β1 (TGF-β1) were evaluated by quantitative real-time PCR (qRT-PCR) and Western blot.Primary HPFs were cultured from excised pterygium tissues using tissue block adhesion method, and cell morphology was observed.Vmentin and cytokeratin were identified by immunofluorescence staining.HPFs were divided into recombinant human LRG1 (rhLRG1) group and blank control group treated with or without 10 μg/ml rhLRG1 for 24 hours, respectively, and cell migration was evaluated via scratch assay.Additionally, HPFs were divided into blank control group, LRG1 overexpression group and LRG1 knockdown group.HPFs in LRG1 overexpression group and LRG1 knockdown group were transfected with LRG1 overexpression plasmids and small interfering RNA for 24 hours, respectively.TGF-β1 mRNA level was evaluated by qRT-PCR and expression of TGF-β1, fibronectin (FN), type Ⅲ collagen (COL3), and α-smooth muscle actin (α-SMA) proteins were evaluated by Western blot.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the First Affiliated Hospital of Harbin Medical University (No.2022IIT026).Written informed consent was obtained from each subject.
Results HPFs were successfully isolated, exhibiting spindle-shaped morphology with whorled arrangement, positive identification for vimentin, and negative immunofluorescence staining for cytokeratin.The migration rate of the rhLRG1 group was (83.01±2.56)%, significantly higher than (50.32±4.97)% of the blank control group ( t=9.59, P<0.001).Immunofluorescence staining results showed that compared with normal conjunctival tissue, LRG1 protein was significantly higher expressed in pterygium tissue and was widely distributed in fibrous connective tissue and epithelial layer.Both mRNA and protein levels of LRG1 and TGF-β1 were significantly higher in the pterygium group than in the normal control group (mRNA: t=10.18, 6.15, both P<0.05.protein: t=6.83, 8.79, both P<0.05).In the LRG1 overexpression group, mRNA level of TGF-β1, and protein levels of FN, COL3 and α-SMA were significantly increased compared with the blank control and LRG1 knockdown groups (all P<0.05).
Conclusions LRG1 promotes fibrosis and enhances the migration ability in HPFs, and its mechanism may be associated with the upregulation of the TGF-β1 signaling pathway.