title: Pulsed light irradiation improves behavioral outcome in a rat model of chronic mild stress.
abstract: OBJECTIVE
  Transcranial laser therapy (TLT) has been used successfully for the treatment of stroke in animal models and clinical trials. These results support the hypothesis that TLT could be used to treat other central nervous system conditions, such as depression. Current therapy for depression emphasizes pharmaco-therapeutics. However, these interventions often cause unwanted side effects. Here, TLT as a treatment for depression was studied in a rat model of chronic mild stress (CMS).
  
  
  METHODS
  Wistar rats were randomized into four experimental groups (n = 8): (1) No-stress; (2) stress without treatment (Stress); (3) stress treated with an antidepressant (Drug); and (4) stress treated with TLT (TLT). The rats in the stress groups were exposed sequentially to a variety of mild stressors for 8 weeks. Rats were weighed weekly. After 5 weeks of stressing, the Drug group received a daily injection of fluoxetine (10 mg/kg), and the TLT group was irradiated transcranially 3 times a week (810 nm wavelength laser, 3 mm diameter probe, 350 mW peak power, 100 Hz with 20% duty cycle, 2-minute treatment time, 120 J/cm(2) average energy density on skin surface). After 3 weeks of treatment, a forced swimming test (FST) was performed and recorded for behavioral assessment. Animals were euthanized after 8 weeks of the study.
  
  
  RESULTS
  The No-stress group had significantly higher body weight than stress groups from week 5 (P < 0.05). No weight difference was found between the stress groups before treatment. However, the Drug group had significantly less body weight than both Stress and TLT groups after 2 weeks of treatment (P < 0.05). FST showed that the Stress group had significantly more immobility than the No-stress group (P < 0.05). Both Drug and TLT groups had significantly less immobility than the stress group (P < 0.05). There was no significant difference in immobility between both Drug and TLT groups (P = 0.62).
  
  
  CONCLUSIONS
  TLT was comparable to fluoxetine in improving the behavioral outcome after CMS. TLT did not cause weight loss, which is consistently seen in patients treated with fluoxetine. This study demonstrates that TLT has potential as an effective treatment for depression.
authors.affiliation: Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
authors.forename: Xingjia
authors.initials: X
authors.lastname: Wu
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Alberico
authors.forename: Helina
authors.initials: H
authors.lastname: Moges
authors.forename: Luis
authors.initials: L
authors.lastname: De Taboada
authors.forename: Clark E
authors.initials: CE
authors.lastname: Tedford
authors.forename: Juanita J
authors.initials: JJ
authors.lastname: Anders
mesh_terms: D000818:Animals; D018687:Antidepressive Agents, Second-Generation / Q000627:therapeutic use; D001526:Behavioral Symptoms / Q000145:classification / Q000628:therapy; D002908:Chronic Disease; D005080:Exercise Test; D005473:Fluoxetine / Q000627:therapeutic use; D008297:Male; D010789:Phototherapy / Q000379:methods*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013315:Stress, Psychological / Q000628:therapy*; D013550:Swimming
chemical_list: D018687:Antidepressive Agents, Second-Generation; D005473:Fluoxetine