In an experimental tear-deficiency dry eye mouse model mimicking human non-Sjögren’s syndrome keratoconjunctivitis sicca study, IL-1β, tumor necrosis factor-α (TNF-α), and matrix metalloproteinase-9 (MMP-9) were significantly upregulated in the corneal and conjunctival epithelia [9,10], and both corticosteroid and doxycycline suppressed the expression of MMP-9, IL-1β, IL-1α, and TNF-α [11]. This evidence concerns the gene MMP9 and dry eye syndrome.