Endothelin-1 increase in aqueous humour caused by frequency-doubled Nd:YAG laser trabeculoplasty in rabbits

Eye (Lond). 2001 Dec;15(Pt 6):781-5. doi: 10.1038/eye.2001.249.


Purpose: To study the effect of Nd:YAG laser trabeculoplasty (LT) on endothelin-1 (ET-1) concentration of aqueous humour and intraocular pressure (IOP) in rabbits.

Methods: One eye of each of 18 pigmented rabbits was subjected to 360 degrees LT with a frequency-doubled Nd:YAG laser (532 nm), and IOP was measured with a Tono-Pen tonometer before treatment. Post-LT IOP measurements followed by aqueous humour aspiration were performed under general anaesthesia at 3 and 12 h and 1, 3 and 7 days after the treatment. The concentration of ET-1 in aqueous humour was measured by means of a radioimmunoassay.

Results: In the eyes that had undergone LT, the concentrations of ET-1 in the aqueous humour were significantly increased at 3, 12 and 24 h after the treatment compared with the contralateral eyes. ET-1 concentrations at 3 and 7 days after LT, however, did not differ significantly from the corresponding contralateral control values. IOP increased following the treatment at 3 and 12 h. IOP values were significantly lower in the treated eyes at 1, 3 and 7 days after the treatment than in the control eyes.

Conclusions: The results show that LT in rabbits was followed by an immediate and short-term increase in aqueous humour ET-1 that might be caused by leakage from uveal tissue. This may be responsible for the release of prostaglandins causing the IOP increase and inflammatory complications of LT.

MeSH terms

  • Animals
  • Aqueous Humor / chemistry
  • Aqueous Humor / metabolism*
  • Endothelin-1 / analysis
  • Endothelin-1 / metabolism*
  • Intraocular Pressure
  • Laser Therapy*
  • Rabbits
  • Radioimmunoassay / methods
  • Time Factors
  • Trabeculectomy*


  • Endothelin-1