Relative biological effectiveness of fast neutrons for apoptosis in mouse hair follicles.

Hae-June Lee; Sung-Ho Kim

This study compared the effects of high linear energy transfer (LET) fast neutrons on the induction of apoptosis in the hair follicles of ICR mice with those of low LET 60Co γ-rays. The changes that occurred from 0 to 24 h after exposing the mice to either 2 Gy of γ-rays (2 Gy/min) or 0.8 Gy of neutrons (94 mGy/min, 35 MeV) were examined. The maximum frequency was found at 12 h (γ-rays) or 8 h (neutrons) after irradiation. The mice that received 0-8 Gy of γ-rays or 0-1.6 Gy of neutrons were examined 8 h after irradiation. The dose-response curves were analyzed using the best-fit curve model. The dose-response curves were linear-quadratic, and a significant relationship was found between the frequency of apoptotic cells and the dose. The morphological findings in the irradiated groups were typical apoptotic fragments in the matrix region of the hair follicle, but the spontaneous existence of apoptotic fragments was rarely observed in the control group. In the presence of an apoptosis frequency between 2 and 14 per follicle, the relative biological effectiveness values of neutrons in small and large follicles were 2.09 ± 0.30 and 2.15 ± 0.18, respectively.

NEUTRONS; APOPTOSIS; HAIR follicles; DOSE-response relationship in biochemistry; ENERGY storage; LABORATORY mice

Journal of Veterinary Science, 2007, Vol 8, Issue 4, p335

1229-845X

Academic Journal

10.4142/jvs.2007.8.4.335