title: The effect of low-energy laser irradiation on apoptotic factors following experimentally induced transient cerebral ischemia.
abstract: Apoptosis, or programmed cell death, resulting from cerebral ischemia may be related to decreased levels of anti-apoptotic factors, such as serine/threonine kinase (Akt), phosphorylated Akt (pAkt), pBAD, and Bcl-2, and increased levels of pro-apoptotic factors, such as BAD, caspase 9, and caspase 3 activities. In this study, we investigated the effects of low-energy laser (660 nm) irradiation (LLI) on the levels and activity of various anti- and pro-apoptotic factors following ischemia. Transient cerebral ischemia was induced in Sprague-Dawley rats by unilateral occlusion of the middle cerebral artery for 1 h, followed by reperfusion. LLI was then directed on the cerebrum for varying lengths of duration (1, 5, or 10 min at an energy density of 2.64 J/cm², 13.2 J/cm², and 24.6 J/cm², respectively). The expression levels of Akt, pAkt, BAD, pBAD, Bcl-2, caspase 9, and caspase 3 activities were measured 4 days after injury. The levels of Akt, pAkt, Bcl-2, and pBAD were significantly increased following laser irradiation. In addition, LLI significantly decreased caspase 9 and caspase 3 activities caused by ischemia-reperfusion. LLI may protect the brain by upregulating Akt, pAkt, pBAD, and Bcl-2 expression and downregulating caspase 9 and caspase 3 expression following transient cerebral ischemia. This modality is a promising protective therapeutic intervention after strokes or other ischemic events.
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong.
authors.forename: K K
authors.initials: KK
authors.lastname: Yip
authors.forename: S C L
authors.initials: SC
authors.lastname: Lo
authors.forename: M C P
authors.initials: MC
authors.lastname: Leung
authors.forename: K F
authors.initials: KF
authors.lastname: So
authors.forename: C Y
authors.initials: CY
authors.lastname: Tang
authors.forename: D M Y
authors.initials: DM
authors.lastname: Poon
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D053148:Caspase 3 / Q000378:metabolism; D002546:Ischemic Attack, Transient / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D028022:Low-Level Light Therapy; D008297:Male; D010766:Phosphorylation / Q000528:radiation effects; D010865:Pilot Projects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D051025:bcl-Associated Death Protein / Q000378:metabolism
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D051025:bcl-Associated Death Protein; D051057:Proto-Oncogene Proteins c-akt; D053148:Caspase 3