Effects of Glutathione-depleting Drug Buthionine Sulfoximine and Aging on Activity of Endothelium-derived Relaxing and Contracting Factors in Carotid Artery of Sprague–Dawley Rats

Abstract

The role of the antioxidant glutathione (GSH) in mediating endothelial (dys)function, and how that role may depend on age, is unclear. The main purpose of the current study was to investigate the effect of 10-day treatment with the GSH-depleting drug l-buthionine sulfoximine (BSO) on endothelium-derived relaxing factor and endothelium-derived contracting factor activities in the isolated common carotid artery (CCA) of Adult and Aging animals. CCA blood pressure and flow were unaffected by age or BSO. Endothelium-derived relaxing factor activity, examined in precontracted CCA as relaxation to cumulative acetylcholine (ACh), was largely nitric oxide synthase (NOS) mediated and was not different between Adult and Aging animals at lower ACh; however, at higher ACh, relaxation was blunted in Aging CCA, an effect abolished by cyclooxygenase (COX) inhibition but not by NOS inhibition nor by the reactive oxygen species (ROS) inhibitors 4-hydroxy-TEMPO or Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin,tetratosylate,hydroxide. Specific examination of endothelium-derived contracting factor activity in quiescent NOS-inhibited CCA established that higher ACh elicited a contractile response, ∼3.5-fold greater in Aging versus Adult CCA, which was abolished by COX-1-specific inhibition but unaffected by ROS inhibitors. Aging was unrelated to changes in liver or vascular tissue GSH or ROS content. BSO was effective in significantly decreasing GSH and increasing ROS content in both animal cohorts. However, NOS-mediated endothelium-derived relaxing factor activity was well preserved and age-related COX-mediated endothelium-derived contracting factor activity was unaffected in response to these BSO-induced perturbations, as were exogenous H2O2-stimulated NOS/non-NOS-mediated relaxation and COX-mediated contractile activities. These data suggest that, regardless of age, chronic partial depletion of GSH in vivo does not necessarily cause endothelium-dependent vasomotor dysfunction.

Antiaging effect of dietary chitosan supplementation on glutathione-dependent antioxidant system in young and aged rats

“…This concurs with the earlier findings (Subramanian and James 2010), which indicated that the higher vulnerability of aged myocardium to peroxidative damage was mainly due to a decline in the level of free radical scavengers. Depletion of GSH results in enhanced lipid peroxidation, and excessive lipid peroxidation can cause increased GSH consumption during aging (Denniss et al 2011), as observed in the present study. GSH protects the cardiac cell membranes from the damaging action of lipid peroxide.…”

The effects of buthionine sulfoximine treatment on diaphragm contractility and SERCA pump function in adult and middle aged rats

“…2011). Briefly, AD CTL rats maintained a stable body weight throughout the treatment period, whereas the body weight in MA CTL rats was significantly decreased by 2.5 ± 0.5%, despite equivalent food and water intake.…”

“…2011). The declines in GSH:GSSG ratios (Liver: AD 31% and MA 25% vs. Diaphragm: AD 83% and MA 71%) and reductions in GSH content (Liver: AD 42% and MA 60% vs. Diaphragm: AD 96% and MA 95%), were more pronounced in the diaphragm than the liver, suggesting that BSO treatment may have increased ROS/RNS concentrations to an even greater extent in the diaphragm than the liver.…”

“…The animals used in this study were also used to study the effects of GSH depletion in vivo on carotid artery function (Denniss et al. 2011) and apoptotic signaling in skeletal muscle (Dam et al. 2012).…”

Differential Modulation of Nitric Oxide Synthases in Aging: Therapeutic Opportunities

“…As will be discussed, NOS can also act as a $•{\text{O}}_2^{\text{−}}$ generator. Antioxidant enzymes such as superoxide dismutase, glutathione, and catalase are also down-regulated or exhibit decreased activity with aging (Sun et al, 2004; Lund et al, 2009; Denniss et al, 2011; Fleenor et al, 2011). The final consequence is an unbalanced ROS production and NO depletion in detriment of the antioxidant capacity.…”