RESUMO
Located at the interface of the dentin-pulp complex, the odontoblasts are specialized cells responsible for dentin synthesis and nociceptive signal detection in response to external stimuli. Recent studies have shown that the mechanosensitive ion channel PIEZO1 is involved in bone formation and remodeling through the influx of calcium ions, and it is abundantly expressed in odontoblasts. However, the specific role of PIEZO1 in reactionary dentinogenesis and the underlying mechanisms remain elusive. In this study, we found intense PIEZO1 expression in the plasma membrane and cytoplasm of odontoblasts in healthy human third molars, mouse mandibular molars, and human odontoblast-like cells (hOBLCs). In hOBLCs, PIEZO1 positively regulated DSPP, DMP1, and COL1A1 expression through the Ca2+/PI3K-Akt/SEMA3A signaling pathway. In addition, exogenous SEMA3A supplementation effectively reversed reduced mineralization capacity in PIEZO1-knockdown hOBLCs. In vivo, Piezo1 expression peaked at day 7 and returned to baseline at day 21 in a wild-type mice dentin injury model, with Sema3a presenting a similar expression pattern. To investigate the specific role of PIEZO1 in odontoblast-mediated reactionary dentinogenesis, mice with a conditional knockout of Piezo1 in odontoblasts were generated, and no significant differences in teeth phenotypes were observed between the control and conditional knockout (cKO) mice. Nevertheless, cKO mice exhibited reduced reactionary dentin formation and decreased Sema3a and Dsp positive staining after dentin injury, indicating impaired dental pulp repair by odontoblasts. In summary, these findings suggest that PIEZO1 enhances the mineralization capacity of hOBLCs in vitro via the Ca2+/PI3K-Akt/SEMA3A signaling pathway and contributes to reactionary dentinogenesis in vivo.
RESUMO
Objective: To explore the effects of menopausal factor on fine anatomy of bladder, urethra and vagina in women undergoing vaginal delivery. Methods: Gynecological patients in Nanfang hospital from January 2013 to October 2016 were collected, and then the patients whose MRI images quality meet the require of reconstruction, with the history of vaginal delivery experience, without any cesarean section experience, and the first labor time was ≤30 years old were enrolled. The patients who had pelvic floor dysfunction when done MRI examinations were excluded. Finally, 238 cases were randomly selected out, and 238 models of data were reconstructed and measured by Mimics and UG software. The independent t test was used to do the comparison between menopausal group and those not yet menopause. Results: First, we built 238 3D models totally. Second, the parameters related with bladder and urethra: the angle of bladder and urethra, ß angle, urethra pubic angle, α angle, retropubic space, the length between bladder neck and edge of pubic midpoint, and urethral striated muscle thickness of menopausal group were bigger than those of pre-menopausal group. While for the urethra tilt angle, the former group was smaller than that of the latter group. But there was no significant statistical differences between two groups. Third, the parameters related with vagina: the proximal urethral vaginal gap of the post-menopause group was smaller than that of pre-menopausal group, while for the middle and distal urethral vaginal gap, the former group was bigger than that of the latter group. The length and width of vaginal anterior wall of the post-menopausal group were smaller than those of pre-menopausal group. Beside the middle urethral vaginal gap, all the difference between two groups had no statistical meaning. The 2D shape of axial vaginal, H type occupation of the former group was obviously lower than that of the latter group. Conclusions: Menopause has an effect on fine anatomy of pelvic organ. Especially on the shape of vagina, the middle urethral vaginal gap become much wider after menopause, the occupation of shallow concave type become much higher post-menopausal. It means the lateral and backward support function of the urethra and vagina is relatively weakened after menopausal, and the shape of vagina become smaller.
