[The toxic effect of N-methyl-N- nitrosourea on retina in rats].
OBJECTIVE
To observe the toxic effect of N-methyl-N-nitrosourea (MNU) on photoreceptor cells within retina of SD rats.


METHODS
At 50 days of age, 100 female rats received a single intraperitoneal injection of MNU at different doses of 50 mg/kg, 60 mg/kg, 70 mg/kg and 80 mg/kg body weight, respectively. Each group had 6 rats and 4 untreated rats were used as normal control. At 24, 48 and 72 hours and 7 days after the administration of MNU, the animals were sacrificed and both eyes were enucleated immediately and processed for histological examination.


RESULTS
It was found that all doses of MNU could sequentially damage the central and peripheral retina. The first evidence of retinapathy 24 hours after the application of MNU was pyknosis and disruption of photoreceptor cells nuclei and the disorientation of the photoreceptor outer segments; loss of photoreceptor cell deteriorated significantly at 48 hours or 72 hours; the outer nuclear layer and photoreceptor layer were almost completely lost at 7 days.


CONCLUSIONS
The results demonstrated that MNU could selectively damage the photoreceptor cells in the retina of the rats, which was dose-dependent and time-dependent.
Yang
Jinnan
J
Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China.
Lin
Shaochun
S
Hu
Shixing
S
Chen
Kang
K
Deng
Xinguo
X
D000818:Animals; D005260:Female; D008770:Methylnitrosourea / Q000008:administration & dosage / Q000633:toxicity*; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000187:drug effects / Q000473:pathology
D008770:Methylnitrosourea