Functional rescue of N-methyl-N-nitrosourea-induced retinopathy by nicotinamide in Sprague-Dawley rats.
OBJECTIVE
A single intraperitoneal injection of 60 mg/kg body weight of N-methyl-N-nitrosourea (MNU) into rats results in retinal degeneration over a 7-day period in all treated animals. The purpose of this study was to determine whether nicotinamide (NAM) can lead to a functional rescue of the MNU-induced retinopathy.


METHODS
NAM, a water-soluble B-group vitamin (vitamin B( 3)), was administered immediately after MNU injection, and retinas were examined morphologically and functionally.


RESULTS
Morphologically, 1000 mg/kg NAM completely suppressed and 50 mg/kg NAM partially suppressed the photoreceptor cell loss. Functionally, scotopic and photopic electroretinographic (ERG) recordings showed that both rod and cone photoreceptor cells were well protected from MNU damage by 1000 mg/kg NAM and partially protected by 50 mg/kg NAM.


CONCLUSIONS
NAM can protect photoreceptor cells from MNU-induced retinopathy both structurally and functionally.
Kiuchi
Katsuji
K
Department of Pathology, Kansai Medical University, Moriguchi, Osaka 570-8506, Japan.
Kondo
Mineo
M
Ueno
Shinji
S
Moriguchi
Kaei
K
Yoshizawa
Katsuhiko
K
Miyake
Yozo
Y
Matsumura
Miyo
M
Tsubura
Airo
A
D000477:Alkylating Agents; D000818:Animals; D004596:Electroretinography; D005260:Female; D008770:Methylnitrosourea; D009536:Niacinamide / Q000627:therapeutic use*; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000473:pathology; D012174:Retinitis Pigmentosa / Q000139:chemically induced* / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology
D000477:Alkylating Agents; D009536:Niacinamide; D008770:Methylnitrosourea