This in vitro study evaluated the detrimental effect of acute gamma (gamma)-irradiation on rat immature hippocampal neurons. Rat immature hippocampal neurons (0.5 day in vitro) were irradiated with 0~4 Gy gamma-rays. Cytotoxicity was analyzed using a lactate dehydrogenase release assay at 24 h after gamma-irradiation. Radiation-induced cytotoxicity in immature hippocampal neurons increased in a dose-dependent manner. Pre-treatments of pro-apoptotic caspase inhibitors and anti-oxidative substances significantly blocked gamma-irradiation-induced cytotoxicity in immature hippocampal neurons. The results suggest that the caspase-dependent cytotoxicity of gamma-rays in immature hippocampal cultured neurons may be caused by oxidative stress.
Amifostine/pharmacology ; Animals ; Antioxidants/pharmacology ; Caspase 3/metabolism/radiation effects ; Catechin/analogs & derivatives/pharmacology ; Cell Survival/radiation effects ; Cells, Cultured/cytology/enzymology/*radiation effects ; Dose-Response Relationship, Radiation ; Female ; *Gamma Rays ; Hippocampus/cytology/enzymology/*radiation effects ; L-Lactate Dehydrogenase/radiation effects ; Neurons/cytology/enzymology/*radiation effects ; Poly(ADP-ribose) Polymerases/drug effects ; Pregnancy ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effect of pulsed electromagnetic fields (PEMs) on inducing osteoclastic like cell (OLC) formation changes and apoptosis in ovariectomized (OVX) rats bone marrow culture in vitro.

METHODSThirty healthy three-month-old female Wistar rats were either sham-operated (Sham) or ovariectomized (OVX) and randomly divided into three groups: group A (OVX + PEMs, 18 rats), group B (OVX, 6 rats) and group C (Sham, 6 rats); group A was again randomly divided into three groups: A1, A2, A3. The frequencies adopted were 1.5, 2, 75 Hz and 30 minutes for once a day. All rats were fed with normal diet for 3 months, then the bone marrow of all rats were cultured, 2 days later, group A cells (including group A1, A2, A3) were collected and exposed to different frequencies PEMs for 2 weeks (30 min/day). In order to observe the changes of osteoclasts and count their numbers, cells were taken for Wright Giemsa staining, tartrate-resistance acid phosphatase (TRAP) staining and Hoechst 33258 staining.

RESULTSTRAP staining results indicated the number of OLC in group C was the least, then was group A2, A3, A1, B. The number of OLC in group B was remarkably increased (P < 0.01; vs group C, A2). The number of OLC in group B was significantly increased (P < 0.05; vs group A1, A3). Hoechst 33258 staining results indicated the number of apoptosis of OLC in group C was more than other groups, which of group C, A2 was significantly increased (P < 0.05; vs group B).

CONCLUSIONPEMs had decreased the formation of OLC and increased the number of apoptosis of OLC in ovariectomized (OVX) rats bone marrow culture in vitro, the effects of 2 Hz was the best. PEMs would be a new way of osteoporosis therapy.

Acid Phosphatase ; metabolism ; Animals ; Apoptosis ; radiation effects ; Bone Marrow Cells ; cytology ; enzymology ; radiation effects ; Cells, Cultured ; Electromagnetic Fields ; Female ; Isoenzymes ; metabolism ; Osteoclasts ; cytology ; enzymology ; radiation effects ; Ovariectomy ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Rats, Wistar ; Tartrate-Resistant Acid Phosphatase