Penetrability of interleukin-1beta and its effect on the concentration of tumor necrosis factor-alpha and interleukin-6 in the aqueous humor of rabbits treated with interleukin-1beta / 中华医学杂志(英文版)

ABSTRACT

<p><b>BACKGROUND</b>Interleukin (IL)-1beta may effectively decrease introcular pressure (IOP) when administered by subconjunctival injection in normal rabbit. However, IL-1beta is a large molecular agent and an inflammation factor. The aim of this study was to evaluate the penetrability of IL-1beta, and the concentrations of both tumor necrosis factor (TNF)-alpha and IL-6 in the aqueous humor of normal rabbits treated with IL-1beta.</p><p><b>METHODS</b>A total of 170 rabbits were used in the study and were assigned to several different treatment groups as follows 125 of the rabbits were assigned to two groups. In one group, 33 rabbits were injected subconjunctivally with IL-1beta and 39 were injected with saline alone. In the other group, 27 rabbits were given eye drops containing IL-1beta (400 ng/ml) and 26 were given saline alone. Aqueous humor (AH) was drawn and the concentration of IL-1beta within the fluid measured. The IOP was measured in another six rabbits after administration of eye drops containing IL-1beta (400 ng/ml). A further 20 rabbits were assigned to 3 groups as follows eight untreated normal controls; six injected subconjunctivally with IL-1beta; and six injected subconjunctivally with saline alone. AH was drawn and the concentration of TNF-alpha in the fluid was measured. Another 19 rabbits were assigned to 3 groups as follows seven untreated normal controls; and six injected subconjunctivally with IL-1beta; and six injected subconjunctivally with saline alone. AH was drawn and the concentration of IL-6 in the fluid measured. Measurement of cytokine concentration was by radio-immunoassay in all cases.</p><p><b>RESULTS</b>The IL-1beta concentration in the AH was higher in those animals in which it had been administered subconjunctivally (P < 0.01). The IL-1beta concentration in the AH of the animals given eye drops was almost the same as that in the controls (P > 0.05). The administration of IL-1beta in the form of eye drops had little effect upon IOP reduction. Lower TNF-alpha concentrations were seen in the AH after the subconjunctival administration of IL-1beta, but the concentration of IL-6 was the same as in the normal controls.</p><p><b>CONCLUSIONS</b>IL-1beta shows good corneal penetrability after subconjunctival injection into normal rabbit eyes. The IOP reduction induced by IL-1beta is unlikely be associated with an inflammatory response.</p>