Alendronate enhances osteoblastic differentiation with increased expression of Id-1 and Id-2 in pre-osteoblast cell line, MC3T3-E1 / 대한산부인과학회지

OBJECTIVE: Alendronate, a widely used bisphosphonates, acts to inhibit bone resorption by interfering with the activity of osteoclasts. Recently, it has been reported that alendronate also may increase bone proliferation and osteoblastic differentiation. However, little is known about mechanism of the action of alendronate on osteoblast differentiation, especially in transcription level. Inhibitors of DNA binding/ differentiation (Ids) are helix-loop-helix (HLH) transcription factors and play an important role in BMP-induced osteoblast lineage-specific differentiation. Therefore, this study was aimed to investigate the effect of alendronate on osteoblast differentiation and expression of Id-1 and Id-2. METHODS: MC3T3-E1, pre-osteoblast cell line, were treated with alendronate of various concentrations (10(-9) M-10(-4) M) and time periods (24, 48 and 72 hours). And then, the effect of alendronate on osteoblast differentiation was examined by alkaline phosphatase (ALP) activity and RT-PCR for osteoblast differentiation markers such as ALP, type 1 collagen (Col 1), and osteocalcin (OCN). The expressions of Id-1 and Id-2 were measured by RT-PCR. RESULTS: Alendronate treatment increased not only ALP activity, but also expressions of ALP, Col 1, and OCN. Also, alendronate treatment up-regulated the mRNA levels of Id-1 and Id-2 genes. This alendronate-induced osteoblastic differentiation is more effective in lower doses rather than high doses. CONCLUSION: This study shows that the expression of transcription factor Id-1 and Id-2 was increased in a dose-dependent manner during alendronate-induced osteoblast differentiation.

Distribution of delta sleep-inducing peptide in the newborn and infant human hypothalamus: an immunohistochemical study

The distribution of delta sleep-inducing peptide immunoreactive cell bodies, fibers, and terminal-like structures was investigated in the normal human hypothalamus during the first postnatal year, using immunohistofluorescence and peroxidase anti-peroxidase techniques. Immunolabeled perikarya were relatively few and were mostly scattered through the anterior (preoptic) and mediobasal regions (infundibular nucleus) of the hypothalamus. DSIP-immunoreactive fibers and terminal-like fibers were observed throughout the entire rostrocaudal extent of the hypothalamus. They exhibit high densities in the preoptic region, the organum vasculosum of lamina terminalis, infundibular nucleus and median eminence. Moderate to low densities of DSIP-immunoreactive fibers were observed in the other hypothalamic structures, located in the anterior and mediobasal regions of hypothalamus, such as periventricular, paraventricular, suprachiasmatic, ventromedial, dorsomedial and parafornical nuclei. In the present study, the analysis of the immunohistochemical pattern of DSIP-immunoreactive neuronal elements in the human infant hypothalamus during the first postnatal year provided evidence of the presence of several differences. We have found qualitative age-related changes in the density of DSIP immunoreactivity in several hypothalamic structures such as the anterior region and the median eminence.

The effect of delta sleep-inducing peptide on the EEG and power spectra in rat.

The effects of delta sleep-inducing peptide (DSIP) on the EEG and power spectra of adult male Wistar rats (b.w. 180-220 g) were studied by power spectra analyses of EEG wave forms recorded continuously for 12 h after DSIP administration. The animals were given DSIP i.p. (1 mg/kg). Saline-injected rats served as the corresponding control. Recorded bursts of high amplitude EEG in the 1-9 Hz range (delta and theta) were found to be more frequent in DSIP-treated animals, while power spectra and (delta) wave activity were enhanced in comparison with the control and a statistically significant increase was registered in all experimental points after DSIP (2 h P < 0.05; 4 h P < 0.05; 5 h P < 0.05; 6 h P < 0.05; 7 h P < 0.01; 11 h P < 0.05). In addition, DSIP significantly elevated both the EEG output in the (delta) range and sleep activity. These results suggest that DSIP should be considered as a potential agent for the treatment of sleep disturbances in human medicine.