Influence of physiological conditions on laser damage thresholds for blood, heart, and liver cells.
OBJECTIVE
Damage to blood and other tissues during laser interventions depends mainly upon absorption of laser radiation by cells. The objective of this work was to evaluate the influence tissue-specific physiological factors on photo-damage thresholds of individual cells: Red blood cells (blood), hepatocytes (liver), and miocytes (heart).


METHODS
Laser-induced damage to individual cells was detected and studied with Laser Load Test (LLT). Probability and thresholds of RBC damage after one laser pulse (532 nm, 10 nanoseconds) were obtained experimentally as functions of physiological conditions. Using in vitro models, we have studied influence of the oxygen level, pH, temperature, and cell heterogeneity on RBC, the inhibition of metabolic activity on miocytes and drug toxicity on hepatocytes.


RESULTS
Single laser pulse induced cell lyses through a vapor bubble. The decrease of the O2 level and temperature caused increase of damage thresholds at 532 nm. Deviation of the pH level from neutral to any side caused also the increase of the damage threshold. Inhibition of metabolism of miocytes and toxic damage to hepatocytes also resulted in the increase of the damage threshold.


CONCLUSIONS
Resistance of various tissues at cell level against photo-damage significantly depends on physiological properties of cells. A general rule for such dependence is that the better the cell state the lower its threshold for laser-damage.
Lapotko
Dmitri O
DO
International Center, Luikov Heat and Mass Transfer Institute, Minsk, 220072, Belarus. ld@hmti.ac.by
Lukianova
Ekaterina Y
EY
D000818:Animals; D018929:Cell Culture Techniques; D002839:Chromans / Q000633:toxicity; D004912:Erythrocytes / Q000502:physiology / Q000528:radiation effects*; D022781:Hepatocytes / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007004:Hypoglycemic Agents / Q000633:toxicity; D007834:Lasers / Q000009:adverse effects*; D008297:Male; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000528:radiation effects*; D010100:Oxygen / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013696:Temperature; D045162:Thiazolidinediones / Q000633:toxicity; D000077288:Troglitazone
D002839:Chromans; D007004:Hypoglycemic Agents; D045162:Thiazolidinediones; D000077288:Troglitazone; D010100:Oxygen; C039671:ciglitazone