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. Author manuscript; available in PMC: 2019 Feb 1.
Published in final edited form as: J Orthop Res. 2017 Jul 31;36(2):739–750. doi: 10.1002/jor.23651

Figure 6.

Figure 6

The patellofemoral groove (PFG) is more sensitive to impact-induced MT depolarization than the medial femoral condyle (MFC). (A) Representative confocal images of control and impacted (M2) PFG explants stained for MT polarity at low (top) and high (bottom) magnification. Cartilage is stained with Mitotracker Green (green; all MT), tetramethylrhodamine methyl ester perchlorate (red; polarized/functional MT), and Hoechst 33342 (blue; nuclear counterstain, higher affinity for cells with compromised cell membranes). Red:green fluorescent intensity ratios were calculated on an image-wide basis in multiple low magnification z-stacks for each explant (top) using a custom ImageJ macro. This high-throughput technique was validated by manually drawing ROIs around individual cells at higher magnification (bottom) to calculate R:G ratios on a single-cell basis. (B) MT depolarization occurred in PFG cartilage from both the lower (M1) and higher impact (M2) groups compared to PFG controls. Significant differences were not detected between impact groups from the MFC. Asterisks denote a significant difference compared to control at p <0.05. Error bars = ±s.d.