Effects of shoulder distraction on canine shoulder arthroscopy.

OBJECTIVE: To evaluate the use of the Leipzig distractor during canine shoulder arthroscopy. STUDY DESIGN: Experimental, ex vivo. SAMPLE POPULATION: Paired shoulder joints from 15 large breed canine cadavers. METHODS: Standard lateral shoulder arthroscopy was performed with or without the use of the Leipzig distractor (n = 15 each). Joint space width, procedure time, and visibility and palpability of the intra-articular structures were assessed during the arthroscopy. After the arthroscopic evaluation, each shoulder joint was disarticulated to assess the area and number of iatrogenic articular cartilage injury (IACI) lesions. Sites around the distraction device were assessed for the presence of iatrogenic injury. RESULTS: With shoulder distraction, median joint space width was 4 mm larger (P = .01), IACI area was 9.5 mm2 lower (P = .003), and there were two fewer total number of IACI lesions (P = .004) compared with nondistracted shoulders. The mean total surgery time was 93 seconds shorter (P = .01) in distracted shoulders. Although distraction was associated with increased visibility of the supraglenoid tubercle (P = .015), no significant differences were found for other intra-articular structures for their visibility and palpability. Unexpected lesions at the sites around the distraction device were not encountered. CONCLUSION: Use of the distraction device decreased the area and incidence of IACI lesions and shortened the arthroscopy time. However, no improvement was found in the visibility or palpability of the intra-articular structures. CLINICAL SIGNIFICANCE: Although additional clinical studies are required to evaluate the effect of the distraction device on pathologic articular conditions and intraoperative manipulation, the use of a shoulder distraction device might improve the outcomes of shoulder arthroscopy by decreasing IACI and arthroscopy time.

Optogenetic in vivo cell manipulation in KillerRed-expressing zebrafish transgenics.

BACKGROUND: KillerRed (KR) is a novel photosensitizer that efficiently generates reactive oxygen species (ROS) in KR-expressing cells upon intense green or white light illumination in vitro, resulting in damage to their plasma membrane and cell death. RESULTS: We report an in vivo modification of this technique using a fluorescent microscope and membrane-tagged KR (mem-KR)-expressing transgenic zebrafish. We generated several stable zebrafish Tol2 transposon-mediated enhancer-trap (ET) transgenic lines expressing mem-KR (SqKR series), and mapped the transposon insertion sites. As mem-KR accumulates on the cell membrane and/or Golgi, it highlights cell bodies and extensions, and reveals details of cellular morphology. The photodynamic property of KR made it possible to damage cells expressing this protein in a dose-dependent manner. As a proof-of-principle, two zebrafish transgenic lines were used to affect cell viability and function: SqKR2 expresses mem-KR in the hindbrain rhombomeres 3 and 5, and elsewhere; SqKR15 expresses mem-KR in the heart and elsewhere. Photobleaching of KR by intense light in the heart of SqKR15 embryos at lower levels caused a reduction in pumping efficiency of the heart and pericardial edema and at higher levels - in cell death in the hindbrain of SqKR2 and in the heart of SqKR15 embryos. CONCLUSIONS: An intense illumination of tissues expressing mem-KR affects cell viability and function in living zebrafish embryos. Hence, the zebrafish transgenics expressing mem-KR in a tissue-specific manner are useful tools for studying the biological effects of ROS.