Expression of neurotrophic factors in neonatal rats after peripheral inflammation.
Neonatal peripheral inflammatory insult might result in the alteration of neuronal development in the nociceptive circuit. During early postnatal period, neurotrophins play important roles in neural development and sensory nerve innervation in the central and peripheral nervous systems. In this study, we investigated mRNA expression for neurotrophic factors and their receptors in the dorsal root ganglia of rat pups during postnatal life after peripheral inflammation induced by injection of complete Freund's adjuvant (CFA) into hind paw on postnatal day 1. Our results showed that mRNA expression levels of alpha-calcitonin gene-related peptides, tropomyosin-related kinase-A (trkA), p75 neurotrophin receptor (p75(NTR)), and brain-derived neurotrophic factor (BDNF) elevated significantly after CFA treatment. Such an increase began 1 day after CFA treatment and lasted 2 to 3 days for trkA, p75(NTR), and BDNF. In contrast, there was no change in mRNA expression levels for neurotrophin-4/5, beta-nerve growth factor (beta-NGF), trkB, glial cell line-derived neurotrophin factor, and receptor protein tyrosine kinase protein. Our study demonstrated that neonatal peripheral inflammatory insult might result in molecular changes of neurotrophic factors, particularly in NGF receptors and BDNF, in the process of neuronal development and plasticity in primary afferents during early neonatal period.


CONCLUSIONS
Neonatal peripheral inflammation model has been used for the exploration of neuropathic pain mechanism for years. This work provided further detailed information about possible neurotransmitters and peptides involved in this process. This might also lead to future clinical application.
Chien
Chih-Cheng
CC
Department of Medicine, School of Medicine, Fu Jen Catholic University, Taipei, Taiwan.
Fu
Wen-Mei
WM
Huang
Hsing-I
HI
Lai
Yeur-Hur
YH
Tsai
Yun-Fang
YF
Guo
Shu-Lin
SL
Wu
Tzong-Jeng
TJ
Ling
Qing-Dong
QD
D000276:Adjuvants, Immunologic; D000818:Animals; D000831:Animals, Newborn; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics; D015740:Calcitonin Gene-Related Peptide / Q000235:genetics; D005260:Female; D005620:Freund's Adjuvant; D005727:Ganglia, Spinal / Q000502:physiology*; D015870:Gene Expression; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000235:genetics; D007249:Inflammation / Q000139:chemically induced / Q000503:physiopathology*; D020932:Nerve Growth Factor / Q000235:genetics; D009414:Nerve Growth Factors / Q000235:genetics*; D009419:Nerve Tissue Proteins; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020917:Receptor, trkA / Q000235:genetics; D020813:Receptor, trkB / Q000235:genetics; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor / Q000235:genetics
D000276:Adjuvants, Immunologic; D019208:Brain-Derived Neurotrophic Factor; D051100:Glial Cell Line-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor; C068313:Ngfr protein, rat; D005620:Freund's Adjuvant; D020932:Nerve Growth Factor; D020917:Receptor, trkA; D020813:Receptor, trkB; D015740:Calcitonin Gene-Related Peptide