Constructive effect of exogenous melatonin against osteoporosis after ovariectomy in rats.
OBJECTIVE
To analyze histomorphometric, densitometric and biochemical effects of melatonin on osteoporosis in ovariectomized rats.


METHODS
Wistar rats were divided into 6 groups. Group C: control; Group I: bilateral ovariectomy (OVX); Group II: OVX + vehicle; Group III: OVX + 10 mg/kg/day melatonin (MLT); Group IV: OVX + 30 mg/kg/day MLT; Group V: sham + 10 mg/kg/day MLT. Cortex, trabecula, osteoblast and osteoclast numbers were evaluated on vertebra and femur histomorphometrically. Hydroxyproline analysis was used to determine collagen content of femur and vertebrae. Bone mineral density and bone mineral content were measured.


RESULTS
Trabecular thickness and trabecular area of vertebra and femur and cortical thickness of femur showed remarkable decrease after OVX, but increased after MLT treatment in the OVX+MLT groups. Following OVX, no statistically significant difference was found in number of osteoblasts or osteoclasts, trabecular number or levels of hydroxyproline after treatment with MLT. OVX caused significant decrease in bone mineral density, but treatment with MLT was unable to reverse this effect.


CONCLUSIONS
MLT may trigger microscopic changes in bone, and time of application is critical for clinical recovery. It can be effective in helping treat postmenopausal osteoporosis. However, it is contraindicated in women who have normal-functioning ovaries.
Uslu
Serap
S
Department of Histology and Embryology, Ege University School of Medicine, TR-35100 Izmir, Turkey.
Uysal
Ayşegül
A
Oktem
Gülperi
G
Yurtseven
Mine
M
Tanyalçin
Tijen
T
Başdemir
Gülçin
G
D000818:Animals; D015519:Bone Density; D005260:Female; D008159:Lumbar Vertebrae / Q000187:drug effects / Q000473:pathology; D008550:Melatonin / Q000627:therapeutic use*; D010024:Osteoporosis / Q000188:drug therapy*; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar
D008550:Melatonin