Beneficial effect of glutamine on exercise-induced apoptosis of rat neutrophils.
OBJECTIVE
The effect of a single bout of intensive exercise on apoptosis of rat neutrophils and the possible prevention by glutamine administration was examined. The experiments were performed in sexually immature and sexually mature male rats as to examine the possible involvement of sexual maturation in the effect of exercise.


METHODS
Exercise was carried out on a treadmill for 1 h before rats were killed by decapitation. Aqueous solution of glutamine was given by gavage (1 g.kg-1 body weight), 1 h before exercise. Neutrophils were obtained by intraperitoneal lavage with phosphate-buffered saline (PBS), 4 h after injection of oyster glycogen solution. The cells were then analyzed for apoptosis by flow cytometry and fluorescence microscopy. Pro- and antiapoptotic gene expression was evaluated by reverse transcriptase chain reaction (RT-PCR).


RESULTS
Neutrophils obtained from immature and mature exercised rats showed an increase in DNA fragmentation, chromatin condensation, and phosphatidylserine externalization. This suggests that all neutrophils suffered apoptosis. To study the possible mechanism involved, the production of reactive oxygen metabolites, expression of genes involved in apoptosis and mitochondrial transmembrane potential were examined. Acute exercise raised reactive oxygen metabolites production by neutrophils. Exercise did not change the expression of antiapoptotic (bcl-xL) and apoptotic (bax and bcl-xS) genes in neutrophils from immature rats but caused a significant increase of bax and bcl-xS expression and provoked a significant decrease of bcl-xL expression in cells from mature rats. Exercise also induced a marked loss of mitochondrial depolarization in neutrophils. Oral glutamine supplementation partially prevented the exercise-induced apoptosis in neutrophils from sexually immature and mature rats.


CONCLUSIONS
The protective effect of glutamine on neutrophil apoptosis induced by acute exercise possibly occurs by preservation of mitochondrial function.
Lagranha
Claudia J
CJ
Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1524, 05508-900 São Paulo, SP, Brazil.
Senna
Sueli M
SM
de Lima
Thais M
TM
Silva
Erica  P P
E
Doi
Sonia Q
SQ
Curi
Rui
R
Pithon-Curi
Tania C
TC
D000284:Administration, Oral; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D053938:DNA Fragmentation / Q000187:drug effects / Q000502:physiology; D005973:Glutamine / Q000008:administration & dosage*; D008297:Male; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values
D005973:Glutamine