Objective: To discuss the function of mixed reality (MR) technology in guiding location of intervertebral foramen microscopic puncture and analyze its feasibility and clinical application value. Methods: Sixty patients with lumbar intervertebral disc who were treated between January 2017 to October 2017 were chosen, and classified into navigation group (30 cases) and traditional control (30 cases) according to random number table. Intervertebral foramen microscopic operation was conducted for both groups. MR technology was applied for the navigation group to guide puncture and establish intervertebral foramen microscopic cannula. Traditional C-arm X-ray apparatus was used for traditional group to establish intervertebral foramen microscopic cannula. Intra-operative puncture times, fluoroscopy times, puncture time and VAS score 1d, 3m and 6m after the operation were recorded and compared. Results: Postoperative waist and leg pain symptoms of both groups were relieved obviously, and straight leg raising test for the diseased limb turned to be negative. Intra-operative puncture times, fluoroscopy times, puncture time and operation time had statistical significance decrease. Conclusion: Mixed reality (MR) can accurately guide the establishment of intervertebral foramen microscopic cannula, solve the bottleneck problem of intervertebral foramen microscopic technology, promote puncture success rate, reduce repeated puncture times, avoid by-injury, shorten puncture time and reduce X-ray radiation quantity of operators and patients, so it deserves to be promoted and applied. doi: https://doi.org/10.12669/pjms.36.3.1683 How to cite this:Guo M, Yue S, Wang J, Cui H. Comparative study on the clinical application of mixed reality technology leading micro-invasive intervertebral foramen puncture location and blind puncture location. Pak J Med Sci. 2020;36(3):---------. doi: https://doi.org/10.12669/pjms.36.3.1683 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Chondrocyte apoptosis is an important factor in the development and progression of osteoarthritis (OA). Cryptotanshinone (CTS) can inhibit chondrocyte apoptosis, but the specific mechanism remains unknown. The aim of the present study was to explore how CTS may affect chondrocyte apoptosis. Reverse transcription-quantitative PCR and western blotting were used to validate microRNA (miR)-574-5p, YY1-associated factor 2 (YAF2), Bcl-2 and Bax expression levels. H&E, Safranin O and TUNEL staining assays were used to evaluate the apoptosis of arthritic chondrocytes in vivo . A Cell Counting Kit-8 assay and flow cytometry were performed to detect cell proliferation and apoptosis of chondrocytes in vitro . The methylation level of the miR-574-5p promoter was measured via methylation specific PCR. The degree of chondrocyte apoptosis and the expression levels of YAF2 and Bcl-2 were decreased in the mice with OA, and were increased in the OA + CTS mice, while the expression levels of miR-574-5p and Bax showed opposite changes. Furthermore, the degree of chondrocyte apoptosis and the expression levels of the aforementioned key factors in chondrocytes were consistent with those observed in vivo . The methylation degree of the miR-574-5p promoter was increased by the addition of CTS, and was reduced after the addition of a methylation inhibitor, 5-aza-CdR, indicating that CTS could regulate the methylation of miR-574-5p promoter. The present study suggested that CTS could downregulate the expression of miR-574-5p by regulating its methylation, and thus, could improve YAF2 expression and affect chondrocyte apoptosis.