Table 2.

Effects of NAD⁺ and γGC on post-stress survival and/or TMRM fluorescence

	Cell survival, %
Treatment	No stress	No stress + drug	Stress alone	Stress + drug
γGC (500 μM)	93.7 ± 0.4 (12)	93 ± 0.6 (12)	32 ± 0.7 (24)	30.3 ± 0.8 (12)
NAD+ (5 mM)	85.9 ± 0.8 (23)	81.3 ± 1 (12)	40.9 ± 0.8 (23)	50.5 ± 1† (12)

	TMRM Fluorescence, % no-stress control
[NAD+]	No stress + NAD+	Stress alone	Stress + NAD+
1 mM	96 ± 3 (12)	13 ± 1 (12)	45 ± 2* (12)
10 mM	94 ± 3 (12)	13 ± 1(12)	40 ± 4* (12)

Values are means ± SE, with number of culture wells shown in parentheses. Cell survival was assayed 50 h post-stress for γ-glutamyl cysteine (γGC) and 40 h poststress for NAD⁺, using the live/dead assay described in materials and methods. TMRM fluorescence was assayed 6.5 h after stress termination. NAD⁺ was applied 24 h before heat stress.

^*P < 0.001;

^†P < 0.05 compared with stress alone (sister cultures, 1-way ANOVA with Dunnett's multiple comparison test). Similar results were obtained in 2 additional experiments.