Glutathione peroxidase deficiency exacerbates ischemia-reperfusion injury in male but not female myocardium: insights into antioxidant compensatory mechanisms.
The female sex has been associated with increased resistance to acute myocardial ischemia-reperfusion (I/R) injury. While enhanced antioxidant capacity has been implicated in female cardioprotection, there is little evidence to support this assumption. Previous studies have shown an important role of cellular glutathione peroxidase (GPx1) in protection of the myocardium from I/R injury. Whether GPx1 is mechanistic in the protection of female myocardium, post-I/R, has not been examined. We utilized a murine model with homozygous deletion of GPx1 and examined its impact on postischemic myocardial recovery in male and female mice. Following I/R, male GPx1(-/-) hearts were more susceptible to contractile and diastolic dysfunction, and this was associated with increased protein carbonyls, a marker of oxidative stress. In contrast, GPx1 deficiency in female hearts did not exacerbate dysfunction or oxidative stress post-I/R. Both wild-type and GPx1(-/-) female hearts exhibited reduced creatine kinase leakage and a more favorable ascorbate redox status compared with males. Following I/R, female GPx1(-/-) hearts showed a comparable decrease in glutathione redox status as their male counterparts; however, they exhibited a greater decrease in nitrate-to-nitrite ratio, suggesting a higher consumption of nitrate in female GPx1(-/-) hearts. Our findings demonstrate that GPx1 is critical for cardioprotection during I/R in male, but not female, mice. The maintenance of cardioprotection in female mice lacking GPx1 post-I/R may be due to an improved ascorbate redox homeostasis and enhanced nitrate-to-nitrite conversion, which would predictably be accompanied by enhanced production of cardioprotective nitric oxide.
Lim
Chee Chew
CC
Department of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2220 Pierce Ave., PRB 340, Nashville, TN 37232, USA. chee.lim@vanderbilt.edu
Bryan
Nathan S
NS
Jain
Mohit
M
Garcia-Saura
Maria F
MF
Fernandez
Bernadette O
BO
Sawyer
Douglas B
DB
Handy
Diane E
DE
Loscalzo
Joseph
J
Feelisch
Martin
M
Liao
Ronglih
R
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D003402:Creatine Kinase / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000172:deficiency* / Q000235:genetics; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009200:Myocardial Contraction; D015428:Myocardial Reperfusion Injury / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology; D009566:Nitrates / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D020127:Recovery of Function; D012737:Sex Factors; D013997:Time Factors; D016277:Ventricular Function, Left; D000094765:Glutathione Peroxidase GPX1
D000975:Antioxidants; D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide; D005979:Glutathione Peroxidase; D003402:Creatine Kinase; D005978:Glutathione; D001205:Ascorbic Acid; D000094765:Glutathione Peroxidase GPX1; C000722068:Gpx1 protein, mouse