Abstract
Purpose: :
To determine the concentrations of the proteolytic enzyme MMP–9 and the inflammatory interleukins IL–1ß and IL–6 in the tear film of patients with different ocular surface disorders using ELISA and HPLC.
Methods: :
The concentration of matrix metalloproteinase 9 (MMP–9) was measured by enzyme–linked immunoadsorbent assay (ELISA) in five groups: 1) control, 2) blepharitis, 3) ocular allergic disease, 4) dry eye and 5) cataract surgery (immediate postoperative period). Interleukin 1ß (IL–1ß) and interleukin 6 (IL–6) concentrations were determined by high performance liquid chromatography (HPLC) in four groups: 1) control, 2) blepharitis, 3) ocular allergic disease and 4) cataract surgery. IL–1ß and IL–6 were determined in tear film from the same patients, whereas MMP–9 was measured in different patients. Statistical comparisons between groups were performed using the Mann–Whitney U test (level of significance: P<0.05).
Results: :
MMP–9 levels were significantly elevated in ocular allergic disease (5.6 fold; 132.33 ± 77.99 ng/ml; P<0.001), dry eye (4.1 fold; 97.25 ± 49.5 ng/ml; P<0.001), cataract surgery (3.6 fold; 83.7 ± 61.59 ng/ml; P<0.001) and blepharitis (2.5 fold; 58.56 ± 30.1 ng/ml; P=0.013), compared with controls (23.61 ± 17.4 ng/ml). The concentration of IL–1ß was significantly elevated only in the blepharitis group (1.9 fold; 450 ± 183.89 µg/ml; P=0.027) compared with controls (238.45 ± 77.56 µg/ml). The concentration of IL–6 was significantly elevated only in ocular allergic disease (2.8 fold; 1.59 ± 0.28 µg/ml; P=0.006; vs. 0.56 ± 0.28 µg/ml in controls).
Conclusions: :
These results indicate a distinct involvement of MMP–9, IL–1ß and IL–6 in the pathogenesis of ocular surface disorders. MMP–9 seems to play a more general role, since increased levels of this molecule were found in all pathological groups. In contrast, IL–1ß and IL6 appear to be more specifically associated with blepharitis and ocular allergic disease respectively.
Keywords: cornea: tears/tear film/dry eye • clinical laboratory testing • cornea: basic science