Visualization of Heat Shock Proteins for Quantifying Laser-Induced Thermal Ablation of Biological Tissues

In laser-based therapeutics, it is important to ablate target tissue with minimal damage to surrounding healthy tissue. Unique properties of lasers allow precise and controlled ablation of tissue. Tightly focusing a short-pulse laser at the desired tissue region and controlling the exposure time by scanning the beam at the target can minimize corresponding collateral damage [1]. Even so, design of effective laser-based ablation procedures requires an understanding of the extent of laser-induced damage for given laser parameters (power, intensity, duration, etc.). Therefore, the instantaneous and effects over time of laser irradiation in live tissue should be studied. Instantaneous effects can be quantified by measuring thermal effects of laser irradiation on tissue. Depending on the application, threshold temperature is necessary to make permanent or temporary changes in tissue structure [1]. The temperature profile around the laser-irradiated region gives insight into radial energy spread and the extent of damage in tissue surrounding the ablation zone. In order to investigate the effects over time of laser irradiation of tissue, we studied the temporal expression patterns heat shock proteins (HSP), members of a class of proteins whose expression patterns change when cells are exposed to elevated temperature or other stressors [2]. We conducted experiments on live anesthetized mice to determine the spatiotemporal expression patterns of heat shock proteins in skin tissue after laser stimulation, both to understand the roles of heat shock proteins in laser-induced tissue damage and repair, and to develop heat shock proteins as tools to illustrate the extent of laser-induced damage and wound healing following irradiation.