[Direct measurement of nitric oxide levels in aqueous humor with selective iso-NO electrode under physiologic conditions and after extracapsular cataract extraction and artificial lens implantation with PMMA in experiments with rabbits].

PURPOSE

To estimate the level of the nitric oxide (NO) within the aqueous humor of the rabbit eye after ECCE and PMMA artificial lens implantation using selective, nitric oxide sensitive electrode Iso-NO. We analysed the NO level during early postoperative period between the 1st and the 5th day.

MATERIAL AND METHODS

We examined 30 gray rabbits (weighing 3.0-3.5 kg). Just before surgery, samples of aqueous humor were aspirated to control the NO level in physiological condition. Lens was extracted with ECCE (envelope) technique. In 15 eyes PMMA IOL were implanted and 15 eyes were left aphacic. The aqueous samples were also collected 1, 3, 5 days after surgery. Nitric oxide in each sample was estimated directly with selective, nitric oxide sensitive electrode Iso-NO. Changing values of the NO concentration during the examination were expressed using evaluation of field under curve in the absolute values. Such results were compared with control group.

RESULTS

During physiological conditions the mean value of the field under curve of the NO concentration was estimated as 4987.29 +/- 895.89. After ECCE with or without PMMA artificial lens implantation the levels of the NO were higher as compared to the control group. After ECCE and PMMA artificial lens implantation the highest level of NO was estimated on the 3rd postoperative day (7978.98 +/- 949.77). During the examinations the fields under curve of NO concentration were estimated as 6626.30 +/- 1176.53 and 6288.19 +/- 604.90 (on the 1st and the 5th days, respectively). On all postoperative days, values of the field under curve of NO were significantly higher as compared to the control group. In contrast, after ECCE without lens implantation the highest value of NO field under curve, was estimated on the 1st postoperative day as 11727.83 +/- 1032.44. During the examinations, the fields under curve of NO concentration were estimated as 9841.52 +/- 698.06 and 5446.96 +/- 568.47 (on the 3rd and the 5th postoperative days, respectively). Moreover, on all days of examination the value of NO fields under curve were significantly higher as compared to the control group.

CONCLUSION

The level of nitric oxide in aqueous humor after ECCE with or without artificial lens implantation was higher than in the control group. The highest value of the field under curve was estimated on the 3rd postoperative day after ECCE and PMMA artificial lens implantation and on the 1st postoperative day after ECCE without lens implantation. The use of direct selective electrode Iso-NO is a simple method of nitric oxide estimation in aqueous humor, but the interpretation of results seems to be very difficult. This method may be suitable for comparative estimations of NO during the experimental works.