Abstract： AIM:To explore the relationship of miR-126 and miR-325 in serum and vitreous with the severity of proliferative vitreoretinopathy(PVR).METHODS:A total of 100 cases(100 eyes)with PVR who were treated in our hospital from October 2019 to October 2022 were selected and retrospectively studied.They were divided into a mild group(42 eyes)and a severe group(58 eyes)according to the degree of retinopathy,and another 30 cases(30 eyes)that underwent vitrectomy without retinopathy due to eye trauma in our hospital during the same period were selected as the control group.Fluorescence quantitative PCR was used to detect the expression levels of miR-126 and miR-325 in serum and vitreous;ELISA was used to detect the levels of transforming growth factor β(TGF-β),platelet-derived growth factor(PDGF),vascular endothelial growth factor(VEGF),and tumor necrosis factor α(TNF-α)in serum and vitreous;and Pearson's method was used to analyze the correlation between the serum and vitreous levels of miR-126 and miR-325 correlated with the levels of TGF-β,PDGF,VEGF,and TNF-α;Logistic multifactorial analysis was used to analyze the influencing factors for the occurrence of severe PVR.RESULTS:Compared with the control group,miR-126 levels in serum and vitreous of PVR patients were decreased and lower in the severe PVR group than in the mild PVR group(both P＜0.05);miR-325 levels were increased and higher in the severe PVR group than in the mild PVR group(both P＜0.05).TGF-β,PDGF,VEGF,and TNF-α levels in serum and vitreous were increased in the severe PVR group compared to the mild PVR group(all P＜0.05).The miR-126 levels in serum and vitreous of patients with PVR were negatively correlated with miR-325,TGF-β,VEGF,TNF-α,and PDGF levels(all P＜0.05),and miR-325 was positively correlated with TGF-β,VEGF,TNF-α,and PDGF levels(all P＜0.05).Logistic regression analysis showed that miR-325,TGF-β,PDGF,and TNF-α were all independent risk factors for the development of severe PVR in serum and vitreous,and miR-126 was an independent protective factor for the development of severe PVR in serum and vitreous(P＜0.05).CONCLUSION:With the aggravation of PVR,miR-126 expression in serum and vitreous decreased while miR-325 expression increased and correlated with TGF-β,TNF-α,VEGF,and PDGF.