Helium-Neon laser irradiation of hepatocytes can trigger increase of the mitochondrial membrane potential and can stimulate c-fos expression in a Ca2+-dependent manner

✍ Scribed by Margherita Greco; Rosa A. Vacca; Loredana Moro; Elda Perlino; Vito A. Petragallo; Ersilia Marra; Salvatore Passarella

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 196 KB
• Volume: 29
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/lsm.1137

✦ Synopsis

Abstract

Background and Objective

To gain some insight into the photostimulation of isolated hepatocytes irradiated with Helium‐Neon (He‐Ne) laser light certain biochemical events were studied with respect to two mechanisms: i) the direct light dependent activation of certain biochemical events investigated in intact cells and isolated mitochondria, ii) the indirect stimulation of processes per se light independent.

Study Design/Materials and Methods

Irradiation of either isolated hepatocytes or isolated rat liver mitochondria was carried out with He‐Ne laser (wavelength, 632.8 nm; fluence, 0.24 J cm^−2^; fluence rate, 12 mW cm^−2^). Changes in mitochondrial membrane potential in isolated hepatocytes were monitored using the cationic probe safranine. The c‐fos expression was studied by Northern blot and immunoblot analysis.

Results

As a result of irradiation, increase of the mitochondrial membrane potential was found to occur in irradiated hepatocytes both in the presence or in the absence of CaCl~2~. The hyperpolarization of the mitochondrial membrane is assumed to cause an increase in mitochondrial Ca^2+^ uptake that was measured in isolated mitochondria. Finally, an increase in c‐fos expression was found in irradiated hepatocytes when incubated in the presence of CaCl~2~.

Conclusion

This paper gives additional information on the mechanism by which He‐Ne laser light, either directly or in a cascade‐like effect dependent on increase in cell Ca^2+^, can cause cell stimulation. Lasers Surg. Med. 29:433–441, 2001. © 2001 Wiley‐Liss, Inc.