The aim of this article is to study the effect of tumor necrosis factor alpha (TNF-α) on the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in keratoconus fibroblasts in vitro. Normal cornea and keratoconus fibroblasts were extracted using enzyme digestion method and were cultured in the medium containing TNF-α (0, 10 and 100 ng/mL). The expression of MMPs proteins in the supernatant of corneal fibroblasts and the expression of TIMPs in the normal cornea and keratoconus fibroblasts were detected by Western blot and real-time quantitative polymerase chain reaction respectively. The active form of MMP1 could be detected in the supernatant of keratoconus fibroblasts and upregulated by TNF-α. TNF-α could increase the protein expression of MMP2, MMP3, MMP9 in the supernatant of keratoconus fibroblasts and decrease the gene expression of TIMP1, TIMP2 in keratoconus fibroblasts. The increased MMPs and the decreased TIMPs can increase the degradation of the extracellular matrix. TNF-α may play an important role in the occurrence and development of keratoconus by regulating the expression of MMPs/TIMPs.
Study of the mechanical properties of in vivo corneal materials is an important basis for further study of corneal physiological and pathological phenomena by means of finite element method. In this paper, the elastic coefficient (E) and viscous coefficient (η) of normal cornea and keratoconus under pulse pressure are calculated by using standard linear solid model with the data provided by corneal visualization scheimpflug technology. The results showed that there was a significant difference of E and η between normal cornea and keratoconus cornea (P < 0.05). Receiver operating characteristic curve analysis showed that the area under curve (AUC) for E, η and their combined indicators were 0.776, 0.895 and 0.948, respectively, which indicated that keratoconus could be predicted by E and η. The results of this study may provide a reference for the early diagnosis of keratoconus and avoid the occurrence of keratoconus after operation, so it has a certain clinical value.