Expression of MMP and TIMP in cornea cells after LASIK with different residual stroma bed in rabbits

Objective To study the influence of different residual cornea bed of laser in situ keratomileusis (LASIK) on the collagenic construction of cornea through investigating the expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in cornea cells for different residual stroma bed after LASIK for six months. Methods Twenty -eight New Zealand white rabbits (56 eyes) were divided into four groups at random. Fourteen eyes were controled as group A. Rabbits in groups B, C and D were per- formed LASIK with residual stroma bed of the cornea 70% , 50% and 30% respectively. Six months after operation, aquired the cornea tissue to perform indirect enzyme-linked immuno-absordent assay (ELISA) for the quantity of Gelatinase, zymography for the activities of Gelatinase, reverse transcription-polymerase chain reac- tion (PT-PCR) for the expression of tissue inhibitors of metallopro- teinase-2 (TIMP-2) mRNA. The changes of cornea structures were observed by transmission electron microscope. Results ① Indirect enzyme-linked immuno-absordent assay (ELISA) proved that MMP-2 and MMP-9 were expressed in cornea cells in groups of A, B, C, D after LASIK for six months, and MMP-2 has no significant dif- ference between the four groups (F=0.456, P0.05), MMP-9 has no significant difference too (F=1.676, P0.05). ②Reverse tran- scription -polymerase chain reaction (PT -PCR) showed that the TIMP-2 mRNA was expressed in cornea cells in groups of A, B, C, D after LASIK for six months, and there was no significant difference between the four groups (F=0.003, P0.05). The expres- sion of the TIMP-2 mRNA was increase with the artherectomy in- tensity. Conclusion MMP-2, MMP-9 and TIMP-2 are expressed in normal cornea cell of rabbit, and there are no significant differ- ence between the four groups after LASIK for six months. If has the keratoconus occurrence because surgery itself causes the colla-gen degeneration to increase by no means causes, possibly it is re- lated to the heredity susceptivity and biological mechanics, affects the mechanism pending further to study specifically.