RSUSSH 2020
IN20-184 MicroRNA Profiles Associated with Bone Healing of the Extraction Socket in Medication-Related Osteonecrosis of the Jaw in Rat Model: A Pilot Study
Presenter: Mr.Thapakorn Surajkulwatana
Chulalongkorn University, Thailand
Abstract
Bisphoshonates (BPs) are widely used for treating osteoporosis, multiple myeloma, breast cancer, and bone metastasis cancer. Trauma or tooth extraction in patients treated with BPs can lead to MRONJ development because of its mechanism of action by which interferes bone homeostasis and angiogenesis. Once MRONJ has occurred, this hard-to-cure disease posed the risk of having poor quality of life to the patients. The application of miRNA for curing the diseases is now being of interest in the medical field. Aiming at elucidating the role of miRNAs in the pathogenesis of MRONJ, a rat model was used in creating MRONJ and the expression of candidate miRNAs was evaluated in this study. Twelve rats were randomly divided into 3 groups; 1) zolendronate plus dexamethasone-treated group (Zol), 2) dexamethasone-treated group as a vehicle (Dex), and 3) control group which receiving normal saline solution (NSS). Tooth extraction was performed after 2 weeks of BPs administration. The MRONJ occurred in extraction sockets were confirmed by clinical appearances which are micro-CT, and histological analysis at Day14 and 28 post-extraction. Bone samples from extraction sites were collected for miRNA analysis. In this study, MRONJ in a rat model was successfully established in Zol group. The miRNA analysis revealed an upregulation of 6 candidate miRNAs involving in an inhibition of osteoblast maturation (miR-23a-3p, miR-23b-3p, miR27a-3p and miR-24-3p) and anti-angiogenic activity (miR-34-5p and miR-652-3p). The expression of miR-23a-3p and miR-23b-3p were 12- to 14-fold upregulation comparing with the control group. This study suggested the certain miRNAs, especially miR-23, affected the development of MRONJ.
Citation format:
Surajkulwatana, T., Suphanantachat Srithanyarat, S., & Vacharaksa, A.. (2020). MicroRNA Profiles Associated with Bone Healing of the Extraction Socket in Medication-Related Osteonecrosis of the Jaw in Rat Model: A Pilot Study. Proceeding in RSU International Research Conference, May 1, 2020. Pathum Thani, Thailand.QUESTIONS & ANSWERS
Intersting study. I would like to ask some questions
1) According to micro-PCR array analysis, were the results similar or different from previous study?
2) Could you explain more detail how to locate the woud site by microCT? (Because of size of wounds are unequal)
Thank you
Dear visitor, THANYAPORN KANGWANNARAONGKUL (VISITOR)
Thank you for your comment and questions.
Question 1: According to micro-PCR array analysis, were the results similar or different from
previous study?
Answer: To our knowledge, quite a few studies have investigated the role of miRNAs in controlling the pathophysiological mechanisms of MRONJ. In terms of the study related to MRONJ in rat model, there is the only one study by Yang et al. 2018 that has demonstrated an upregulation of miR23a in serum of MRONJ-rat. This study also further suggested that miR23a could be considered as one of the candidates circulating biomarkers to diagnose BRONJ. Of the 8 candidate miRNAs we have studied, our results found 12-fold upregulation of miR23a in bone tissue sample of MRONJ-rat. miR23a is known as one of the miRNAs that has a role in suppressing osteoblast differentiation. For the rest of 7 candidate miRNAs, currently, there is yet no study conducted to demonstrate their roles in regulating the pathophysiological mechanisms of MRONJ. However, all 8 candidate miRNAs that were chosen for analyze in our study have been well-documented as involving in controlling angiogenic activity and bone remodeling, the key mechanisms in the pathogenesis of MRONJ. Our pilot study found that the miRNAs associated with osteoblast inhibition and anti-angiogenic activity were upregulated in MRONJ-group compared with the control group. Please, refer to our manuscript for more details.
Question 2: Could you explain more detail how to locate the wound site by microCT? (Because of
size of wounds are unequal)
Answer: To assess the wound site, a region of interest (ROI) was established by means of the
following methods;
- The axial view was used to identify the interproximal crestal bone between the upper second molar and the extraction socket.
- The micro-CT slice which represented the distance of 0.5 mm apical to the first identifiable alveolar crest was selected as the slice of interest.
- The ROI was created by making the square with the size of 0.5 x 0.5 mm2 at the center of an extraction socket on this slice.
- To determine bone volume in the extraction socket, the volume of interest (VOI) of 0.5 x 0.5 x 0.5 mm3 per extraction socket was established by using the ROI as a reference.
- Bone volumes and gross 3D images were processed and compared among groups using ImageJ software (Fiji, NIH, USA) and 3D viewer (Microsoft, USA).