Fundamental Toxicological Sciences

Paper Details

Fundamental Toxicological Sciences
Vol. 7 No. 6 December 24, 2020 p.287-289
Inhibitory effects of L-NAME, a nitric oxide synthase inhibitor, on decidual cell proliferation in mid-to-late pregnant rats
  • Tatsuya Takizawa (Graduate School of Veterinary Medicine, Azabu University /
Wataru Ishikawa , Shugo Kazama , Takehito Suzuki , Rei Yamana , Yoko Miyazaki , Kazuaki Tanaka , Makoto Usami , Tatsuya Takizawa
Graduate School of Veterinary Medicine, Azabu University
Keywords: BrdU, Cell proliferation, Decidua, Nitric oxide, Rat

The effects of NG-Nitro-L-arginine-methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthase, on decidual cell proliferation were examined to investigate possible NO depletion-mediated mechanisms of reproductive toxicity. Mid-to-late pregnant rats were injected intraperitoneally with L-NAME (100 mg/kg body weight) and 5-bromo-2′-deoxyuridine (BrdU, 100 mg/kg body weight) at 12 hr and 1 hr before sacrifice, respectively, on day 13.5, 17.5, or 21.5, and the BrdU-positive proliferating decidual cells were detected. In control rats, proliferating decidual cells were observed sporadically on days 13.5 and 17.5; however, fewer such cells were observed at day 21.5. L-NAME reduced the number of proliferating decidual cells by approximately half at days 13.5 and 17.5 but not at day 21.5. These results suggested that in mid-to-late pregnant rats, decidual cell proliferation was maintained by a mechanism involving NO signaling, and NO depletion reduced it only to a limited extent. The absent effect at day 21.5 may be due to the low incidence of proliferating decidual cells or the changing role of NO near the term of pregnancy.