Objective To detect the expressions of microRNA-182-5p (miR-182-5p) and signal transduction molecule 7 (SMAD7) in pterygium, and to explore their correlations with clinicopathological characteristics and prognosis of patients.

Methods A total of 150 primary pterygium tissue specimens removed by surgery in the Department of Ophthalmology of authors' hospital from June 2018 to June 2021 were collected for study, and 60 normal bulbar conjunctiva specimens obtained from cataract surgery in the same period were collected as controls. The expression levels of miR-182-5p and SMAD7 mRNA in the samples were measured by real-time fluorescence quantitative polymerase chain reaction (qRT-PCR); the expression level of SMAD7 protein was measured by immunohistochemical staining; the correlation between miR-182-5p and expression level of SMAD7 mRNA in pterygium tissue was analyzed by Pearson method; the dual-luciferase reporter gene experiment was used to verify the targeting relationship between miR-182-5p and SMAD7.

Results In pterygium tissue, the expression level of miR-182-5p was (2.26±0.45), which was higher than (1.05±0.12) in normal conjunctival tissue; the expression level of SMAD7 mRNA was (0.67±0.12), which was lower than (1.03±0.15) in normal conjunctival tissue; the positive expression rate of SMAD7 protein was 23.33%, which was lower than 71.67% in normal conjunctival tissue; the between-group differences mentioned above were statistically significant (P < 0.05). Correlation analysis showed that the expression of miR-182-5p was negatively correlated with SMAD7 mRNA in pterygium tissue (r=-0.536, P < 0.05); the result of dual-luciferase reporter gene experiment confirmed that there was a targeting relationship between miR-182-5p and SMAD7; the expression level of miR-182-5p in the progressive phase was significantly higher than that in the quiescent phase, and the positive expression of SMAD7 in the progressive phase was significantly lower than that in the quiescent phase (P < 0.05); compared with the cured group, the expression level of miR-182-5p in pterygium tissue in the recurrent group was significantly higher, while the expression level of SMAD7 mRNA and the positive expression rate of SMAD7 were significantly lower (P < 0.05).

Conclusion In pterygium tissue, the miR-182-5p is highly expressed while the SMAD7 is low expressed, and both of the two indexes are related to the clinicopathological characteristics and prognosis of patients, which may become the therapeutic targets of pterygium.