Effect of heparin on osteoprotegerin content and cells apoptosis in cervical loop zone of rat lower incisors

Abstract

Objective To investigate the effect of heparin on osteoprotegerin (OPG) content and cells apoptosis in the rat cervical loop zone of rat lower incisors.Methods Twenty-four Sprague-Dawley (SD) rats aged 4 weeks were divided into two groups randomly.The experimental group was subcutaneously injected with heparin at the abdomen per day by the dose of 1 U/g,and the control group was injected with normal sodium (NS) by the same volume.All of the rats were sacrificed after 4 weeks,their right femurs were obtained for measurement of the bone mineral density (BMD),and the mandibles were harvested,decalcified and made into paraffin sections,which would be dealt with hematoxylin and eosin (HE)staining,OPG immunohistochemical staining,and TdT-mediated dUTP nick end labeling (TUNEL) staining.The professional software Image Pro Plus was used to semi-quantitatively analyze the content of OPG.The lower incisor cerv;ical loops were separated and prepared to be observed by transmission electron microscopy (TEM).Results The right femur BMD [(0.185 ±0.006) g/cm2] in experimental group was lower than that in control group [(0.196 ±0.011) g/cm2,P ＜0.05].The Absorbance (A) value of OPG was 0.235 3 ± 0.035 0 in the experimental group and 0.267 3 ± 0.044 4 in control group (P ＞ 0.05).A few odontoblasts and stratum intermedium cells in control group were apoptosis-positive by TUNEL staining;in contrast,there was no apoptosis in the experimental group.The results of TEM examination were similar with TUNEL staining.Conclusion Heparin could lead to osteoporosis and inhibit the apoptosis of odontogenic cells in the rat lower incisor.However,heparin has no significant effect on the OPG content. Key words: Heparin ; Osteoprotegerin ; Apoptosis ; Cervical loop tissue