The expression and significance of inflammatory cytokines and MMP-9 in the tears of the infected eye and contralateral uninfected eye in patients with fungal keratitis

Abstract

Background: We investigated bilateral tear cytokine levels including interleukin (IL)-1β, IL-10, IL-17, tumor necrosis factor (TNF)-α and Matrix metalloproteinase-9 (MMP-9) in patients with fungal keratitis(FK). Meanwhile, we evaluated the relationship between the changes of tear cytokines with corneal perception and pain in infected eyes, and the relationship between tear cytokines and tear film function in contralateral uninfected eyes .Methods : A total of 60(20 FK, 20 contralateral, 20 healthy controls) tear samples were collected prospectively and analyzed by enzyme linked immunosorbent assay(ELISA). Approximately 50 to 60 ul of tear samples in each case were collected. Meanwhile ,we analyzed the changes of visual analogue scale(VAS), tear breakup time (TBUT), Schirmer I test (SIT) and corneal perception compared with healthy controls. Results :The concentrations of IL-1β, IL-10 and IL-17 increased in bilateral eyes compared with healthy controls(P<0.05). The tear concentrations of MMP-9 , TNF-α only significantly increased in affected eyes (P <0.05). Patients with FK showed significant reduction in corneal perception of infected eyes compared with controls(P<0.05). Corneal perception of the normal eyes in FK patients was slightly lower than that of control group, but there was not statistical difference (P>0.05).TBUT and SIT of contralateral uninfected eyes were significantly lower than that of control group(P<0.05), which were significantly correlated with levels of IL-1β, IL-17(P<0.05). SIT were also negatively correlated with MMP-9(P<0.05), while the levels of IL-1β, IL-10, IL-17, TNF-α and MMP-9 in the tears of the healthy control group had no significant correlation with TBUT and SIT indicators(P>0.05).The corneal perception and VAS score of the affected FK eyes showed correlation with IL-1β, IL-17 and TNF-α(P<0.05).In addition, concentration of IL-10 inversely was correlated with VAS (P<0.05). Conclusion: Proinflammatory tear cytokines are elevated in bilateral eyes with unilateral FK as associated with tear film function ,pain and corneal sensitivity.