Long-term changes of prostacyclin secretion in radiation-induced myelopathy
Background: We have previously reported the short-term changes in prostacyclin profile after irradiation of rat cervical cord. Aim: Present research investigated the long-term changes of prostacyclin content. Materials/Methods: Wistar rats in groups of five were irradiated with doses of 2, 4, 6, 15, 25, 30Gy and a single group of 25 with 35Gy X-rays. After 26 and 39 weeks, prostacyclin content was quantified by 6-keto-prostaglandin-F1? (prostacyclin stabilized metabolite) . Specimens were stained routinely for histological studies. Results: The 50% latent period and effective dose were 14.86±1.16 weeks and 25.66±0.54Gy (p<0.0001), respectively. Average ratios of 6-keto-PG-F1? for doses of 2-30Gy were between 78.33-12.93% and 79.48-99.96% for 26 and 39 weeks, respectively. Prostacyclin level after 35Gy shows approximately a 7:1 ratio in comparison to the control group (p<0.002). Histopathological changes in glial and vascular tissues were diagnosed and scored. Prostacyclin bimodal profile was observed. Conclusions: Radiation can cause complex fluctuations of prostacyclin in association with marked histopathological changes.