Studies demonstrated that matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinases-1 (TIMP-1) exhibit important role in corneal defect of rats with alkali burns.OBJECTIVE:
To observe the promoting effect of recombinant human epidermal growth factor (rhEGF) on rats' corneas following alkali burns, in addition, to explore the effect and significance of rhEGF on the expression of MMP-1 and TIMP-1 in alkali burned rats.DESIGN, TIME AND SETTING:
A randomized controlled animal experiment was performed at the Laboratory Animal Center, Liaoning Medical College from March 2008 to May 2009.MATERIALS:
Sixty healthy SD rats, weighting 180-210 g, with 6-8 weeks old, half male and half female. All rats were confirmed that no anterior segment disease before the experiment with slit lamp microscope examination.METHODS:
Sixty rats were randomly divided into experimental and control groups, with 30 animals in each group. After the preparation of corneal alkali burn models, cornea of rats in the experimental and control groups were given rhEGF eye drops, and physiological saline eye drops respectively, fourth a day, consecutive for 21 days. Six rats of each group were killed at days 1, 4, 7, 14 and 21 after operation.MAIN OUTCOME MEASURES:
①Changes of cornea after alkali burned was observed by slit lamp microscope. ②The expressions of MMP-1 and TIMP-1 in cornea were detected with immunohistochemistry and computer image analysis system at different time points.RESULTS:
The slit lamp microscope results showed that the area of corneal ulcer in the experimental group was obvious smaller than the control group at the corresponding time points. The expression of MMP-1 gradually increased and reached a peak level at 14 days after surgery, then began to decrease. TIMP-1 expressed in the early phrase, but later, its activity gradually decreased, reached the lowest level at 14 days, then began to increase, and peaked at 21 days. The level of MMP-1 in the experimental group was greatly lower than that in the control group at each time points. However, the level of TIMP-1 of the experimental group was greatly higher compared with the control group.CONCLUSION:
The rhEGF eye drops can improve effectively the healing of corneal epithelial defect by adjusting the proportion of matrix metalloproteinase and its tissue inhibitor.