[Experimental study on the prevention of after cataract by heparin drug delivery system]

Heparin drug delivery system (HEP DDS) was developed and applied to the experimental animals for the prevention of after cataract.

Thirty New Zealand rabbits (30 eyes) received phacoemulsification, and were randomly divided into 3 groups: normal saline eye dripping (Group A); posterior chamber implantation of carrier drug delivery system (Group B) or HEP DDS (Group C). All eyes were examined by slit-lamp microscopy, the blood and aqueous humor heparin concentrations were measured and the wet weight of posterior capsules was weighed.

(1) In the 12th week after the operation, the number of eyes developed posterior capsule opacification in Groups A, B, and C was 10, 10 and 4, respectively; with statistically very significant difference (chi(2) = 14.09, P = 0.001). (2) Twelve weeks after operation, the average wet weight of the posterior capsules in these 3 groups was (158 +/- 5) mg, (160 +/- 9) mg and (20 +/- 3) mg, respectively; with statistically very significant difference (F = 1 168.99, P = 0.000). (3) The average value of the aqueous humor heparin concentration in group C was (26 +/- 12) mg/L. (4) Light and electron microscopy did not revealed any active cell proliferation in the posterior capsules in Group C; the conjunctiva, cornea, iris, ciliary body and retina remained intact, without obviously toxic reaction. (5) No intraocular hemorrhage occurred during the follow-up period.

The implantation of HEP DDS into the posterior chamber can raise the aqueous humor heparin concentration to a high level and remained for a long period. This procedure can effectively inhibit the occurrence of after cataract, has few toxic and side effects, and is proved to be a safe and effective procedure.