title: Retinal nitric oxide and malonyldialdehyde levels following photodynamic therapy.
abstract: BACKGROUND
  To determine the retinal nitric oxide (NO) and malonyldialdehyde (MDA) levels following photodynamic therapy (PDT).
  
  
  METHODS
  Seven Dutch-belted rabbits received dextrose, while seven others received 2 mg/kg verteporfin infusion over a period of 15 minutes in a dim-lit room. Irradiation to a 1.5 mm diameter intact chorioretinal area in the right eye of verteporfin-infused rabbits, was started 5 minutes after the end of infusion. Three groups were control (dextrose infusion), infusion with verteporfin (left eyes were not irradiated), and irradiation after verteporfin injection (right eyes were irradiated). On the fifth day of the experiment, the eyes were enucleated. The retinas were subsequently frozen and homogenized. Nitrite, a stable end-product of NO and MDA, was measured using the spectrophotometer. Protein concentrations were measured by the Lowry method. Tissue NO and MDA levels were expressed as μmol/gprt and nmol/mgprt, respectively.
  
  
  RESULTS
  The mean retinal NO and MDA levels of the control, infusion, and irradiation groups were 24.67 ± 6.66, 0.11 ± 0.02; 45.90 ± 15.52, 0.21 ± 0.09; and 84.43 ± 14.96 μmol/gprt, 0.58 ± 0.14 nmol/mgprt, respectively. The mean retinal NO levels were significantly elevated in the infusion and irradiation groups compared with the control group ( p :0.004; p :0.001). The mean retinal MDA levels were significantly elevated in the infusion and irradiation groups compared to the control one ( p :0.026; p :0.001). Also the mean retinal NO and MDA levels in the irradiation group were found to be significantly higher than the infusion group ( p :0.018; p :0.018).
  
  
  CONCLUSIONS
  Not only PDT, but also verteporfin infusion alone resulted in NO and MDA level increments in the retina, which might be toxic.
authors.affiliation: Department of Ophthalmology, Firat University School of Medicine, Elazig, Turkey. peykan74@yahoo.com
authors.forename: Peykan
authors.initials: P
authors.lastname: Turkuoglu
authors.forename: Cem
authors.initials: C
authors.lastname: Ozturkmen
authors.forename: Nevin
authors.initials: N
authors.lastname: Ilhan
authors.forename: Julide
authors.initials: J
authors.lastname: Kurt
authors.forename: Orhan
authors.initials: O
authors.lastname: Aydemir
authors.forename: Ulku
authors.initials: U
authors.lastname: Celiker
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Ibrahim
authors.forename: Aymen
authors.initials: A
authors.lastname: Rashid
mesh_terms: D000818:Animals; D008315:Malondialdehyde / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D010778:Photochemotherapy; D011166:Porphyrins / Q000494:pharmacology*; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000378:metabolism*; D015854:Up-Regulation; D000077362:Verteporfin
chemical_list: D011166:Porphyrins; D000077362:Verteporfin; D009569:Nitric Oxide; D008315:Malondialdehyde