title: Age-Related Differences in Neuropathic Pain Behavior and Spinal Microglial Activity after L5 Spinal Nerve Ligation in Male Rats.
abstract: BACKGROUND
  Several studies have reported the involvement of age-related changes in the development of neuropathic pain behaviors. However, limited data are available on the role of age in establishing and maintaining chronic neuropathic pain after peripheral nerve injury.
  
  
  METHODS
  In the present study, we examined age-related neuropathic behavior among rats in 4 age groups: pups (4 weeks old; weight, 60-80 g), juvenile rats (6 weeks old; weight, 120-140 g), and mature rats (10-12 weeks old; weight, 200-250 g). Because the exact contribution of spinal microglia and its association with the development of neuropathic pain remains unknown, we also evaluated the expression of spinal Iba1, a microglial marker, by using western blotting before and 5 days after spinal nerve ligation (SNL) as well as after the daily IP administration of minocycline (30 mg/kg).
  
  
  RESULTS
  Our results showed that SNL-induced mechanical allodynia but not thermal hyperalgesia in mature rats but not in pups (P<0.05 and P<0.01, respectively). The expression of spinal Iba1 in the juvenile rats was significantly lower than that in pups and mature rats (P<0.01). Moreover, administration of minocycline decreased the expression of spinal Iba1 in the pup rats more than in juvenile rats (P<0.001) and in the juvenile rats more than in the mature rats (P<0.05).
  
  
  CONCLUSIONS
  These data suggest that the development of neuropathic behaviors and microglial activation after SNL could be age dependent.
authors: Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors: Hossein
authors: H
authors: Zeinali
authors: Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors: Homa
authors: H
authors: Manaheji
authors: Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors: Jalal
authors: J
authors: Zaringhalam
authors: Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors: Zahra
authors: Z
authors: Bahari
authors: Department of Physiology, School of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran.
authors: Samad
authors: S
authors: Nazemi
authors: Department of Physiology, Faculty of Medicine, Boushehr University of Medical Sciences, Boushehr, Iran.
authors: Mehdi
authors: M
authors: Sadeghi
keywords: Age- related; Allodynia; Hyperalgesia; Iba1