Cytokine and chemokine levels in tears and in corneal fibroblast cultures before and after excimer laser treatment

Purpose

To measure multiple cytokine and chemokine production in tears of myopic patients before and after laser in situ keratomileusis (LASIK) and in human corneal fibroblast (HCF) cultures before and after excimer laser treatment.

Setting

Department of Neuroscience, Ophthalmology Unit, University of Padua, Italy and Vissum-Instituto de Oftalmológico de Alicante, Alicante, Spain

Methods

Tear samples were obtained from 15 myopic patients before LASIK and 1 and 24 hours after LASIK. Quiescent HCF cultures were treated using the same laser energy. Culture medium was collected before treatment and after 1 and 24 hours. Cytokine concentrations were determined using multiplexed bead analysis.

Results

Compared with baseline values, interleukin (IL)-12 tear levels were significantly increased 1 hour after surgery and eotaxin levels were significantly increased at 24 hours (both P<.05). Culture medium of HCF contained high levels of IL-6, IL-8, and monocyte chemotactic protein (MCP)-1 and low levels of IL-1, eotaxin, and regulated on activation, normal T expressed, and secreted (RANTES) cytokine. One hour after treatment, levels of all cytokines were significantly reduced. At 24 hours, IL-1, IL-6, IL-8, and MCP-1 levels were significantly increased compared with values at baseline and at 1 hour while RANTES cytokine and eotaxin levels had returned to baseline levels.

Conclusions

In vivo and in vitro studies showed that after excimer laser treatment, cytokines are released to modulate the wound-healing process; however, they can potentially induce inflammation. However, these types of in vitro studies, although useful for evaluating changes in cytokine profiles before and after treatment, only partially reproduce in vivo corneal behavior.