ABSTRACT
Objective To observe longitudinal changes in the intraocular pressure (IOP),the cornea and iris blood vessels in normal rats with bulb external scleral explants.Methods Totally 18 normal rats were enrolled in the experiment.Conjunctival incisions of the right eyes of these rats were performed,followed by the placement of a balloon catheter under the lateral rectus muscle and inflation at 4-5 ATM.The IOP was measured and iris images were taken longitudinally before and after pressuring and pressure withdrawing respectively.Results IOP was elevated to (40.66 ± 10.55) mm-Hg (1 kPa =7.5 mmHg) immediately after pressing,which was over the baseline (8.45 ± 1.23)mmHg (P=0.000),and then decreased gradually at 15 min,30 min,45min,60 min after pressing,but the IOPs were still greater than the baseline.There were significant differences in IOPs at 15 min,30 min,45 min after pressing and the baseline (all P ＜ 0.05),while no difference in this variable at 60 min after pressing and the baseline (P =0.929).However,the IOP was quickly reduced to (6.09 ± 0.49) mmHg at once after pressure withdrawing,which was below the baseline (P =0.000),and then gradually returned to the baseline at 15 min,30 min after pressure withdrawing.The corneal edema and dilation of iris vessels were observed after pressuring,and following corneal winkle and dilated iris vessels after pressure withdrawing.Conclusion Bulb external scleral explant can result in elevated IOP immediately,then decreased gradually.With the increase of compressing,the IOP of the contralateral eye tends to increase.Bulb external scleral explant may affect uveoscleral outflow pathway of aqueous humor in rats.
ABSTRACT
<p><b>BACKGROUND</b>There are ON- and OFF-pathways in the normal vertebrate retina. Short- and long-flash electroretinogram (ERG) are suitable methods to observe the function of ON- and OFF-pathways in vivo, respectively. It is clear that high intraocular pressure (IOP) might cause dysfunction of cone-dominated photopic negative response (PhNR) in monkeys with high IOP in ON-pathway. However, whether cone-dominated OFF-responses are also affected is less known. The aim of this study was to observe photopic OFF-responses of ERG in monkeys with high IOP.</p><p><b>METHODS</b>Nine monkeys were involved in the experiment from January 2006 to December 2016. High IOP was induced in the right eye by laser coagulation of the mid-trabecular meshwork in five monkeys. Six years after the laser coagulation, both short- and long-flash of the photopic ERG were recorded. Stimulus light was red flashes superimposed on a blue background. Four normal monkeys were examined under the same ERG protocols as controls. Paired t- test was used to compare the difference of each ERG parameter between the lasered eye and the fellow eye. Analysis of variance (ANOVA) with Tukey adjustment was adopted to calculate the differences among the lasered eye, the fellow eye, and the eyes of normal monkeys.</p><p><b>RESULTS</b>The mean amplitude of a-wave (11.73 ± 2.05) and PhNR (8.67 ± 2.44) in lasered eyes was significantly lower than that of a-wave (21.47 ± 3.15) and PhNR (22.05 ± 3.42) in fellow eyes (P = 0.03 and P = 0.01, respectively) in response to short flash. The mean amplitude of d-wave (1.60 ± 0.59) and i-wave (3.13 ± 0.64) was significantly reduced in the lasered eyes than that of d-wave (4.01 ± 0.56) and i-wave (8.79 ± 1.75) in the fellow eyes (P = 0.02 and P = 0.02, respectively) in response to long flash.</p><p><b>CONCLUSIONS</b>Reduced OFF-responses are recorded in monkeys with high IOP when dysfunction of photoreceptor is involved. The reduced OFF-responses to long-flash stimulus show evidence of anomalous retinal circuitry in glaucomatous retinopathy.</p>
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>