Oxidative stress links the tumour suppressor p53 with cell apoptosis induced by cigarette smoke

Figures & data

Table 1. Lung function results.

Variables	Control	CS	CS + Pifithrin-α	CS + NAC
F (bpm)	207 ± 8	210 ± 17	210 ± 7	207 ± 8
TV (ml)	0.19 ± 0.02	0.20 ± 0.08	0.18 ± 0.04	0.20 ± 0.05
MV (ml/min)	39.63 ± 3.73	41.23 ± 8.54 * # &	38.45 ± 5.95	38.61 ± 5.72
RAW (cmH2O/ml/min)	0.26 ± 0.18	0.76 ± 0.18 * # &	0.59 ± 0.18	0.63 ± 0.24
Cdyn (ml/cmH2O)	0.07 ± 0.07	0.05 ± 0.02 * # &	0.07 ± 0.04	0.08 ± 0.03
Ti/Te	1.09 ± 0.10	0.72 ± 0.05 * # &	0.88 ± 0.08	0.84 ± 0.05

* P < 0.05 versus the control group; # P < 0.05 versus the CS + Pifithrin-α group; & P < 0.05 versus the CS + NAC group.

N = 8 mice per group. Values are expressed as means ± standard deviation. CS, cigarette smoke; Cdyn, lung dynamic compliance; F, respiratory rate; MV, minute ventilation volume; NAC, N-Acetylcysteine; Pifithrin-α, p53 inhibitor; TV, tidal volume; RAW, airway resistance; Ti, inspiratory time; Te, expiratory time.

Figure 1. The effects of cigarette smoke on lung histomorphology in mice. N = 8 mice per group. Control group (a); CS group (b); CS + Pifithrin-α group (c); CS + NAC group (d). CS, cigarette smoke; NAC, N-Acetylcysteine; Pifithrin-α, p53 inhibitor.

Figure 2. MLI, DI and AI in mice exposed to cigarette smoke. * P < 0.05 versus the control group; # P < 0.05 versus the CS + Pifithrin-α group; & P < 0.05 versus the CS + NAC group. N = 8 mice per group. Values are expressed as means ± standard deviation. AI, apoptotic index; CS, cigarette smoke; DI, destructive index; MLI, mean linear intercept; NAC, N-Acetylcysteine; Pifithrin-α, p53 inhibitor.

Figure 3. The effects of cigarette smoke on apoptosis of alveolar septal cells in mice. N = 8 mice per group. Control group (a); CS group(b); CS + Pifithrin-α group (c); CS + NAC group (d). CS, cigarette smoke; NAC, N-Acetylcysteine; Pifithrin-α, p53 inhibitor.

Table 2. The activity of T-AOC, CAT, SOD, and MDA in the four groups.

Variables	Control	CS	CS + Pifithrin-α	CS + NAC
T-AOC (U/mg protein)	7.78 ± 2.58	3.10 ± 1.33 * # ※	9.56 ± 1.69	7.51 ± 2.59
CAT (U/mg protein)	22.40 ± 5.12	7.43 ± 0.80 * # ※	21.01 ± 3.39	22.94 ± 5.28
SOD (U/mg protein)	30.19 ± 6.35	13.24 ± 2.84 * # ※	30.75 ± 3.16	25.98 ± 3.19
MDA (U/mg protein)	1.54 ± 0.59	6.93 ± 1.86 * # ※	4.42 ± 0.89 & ▲	1.84 ± 0.45

* P < 0.05 versus the control group; # P < 0.05 versus the CS + Pifithrin-α group; ※ P < 0.05 versus the CS+NAC group; ▲ P < 0.05 versus the control group; & P < 0.05 versus the CS + NAC group.

N = 8 mice per group. Values are expressed as means ± standard deviation. CS, cigarette smoke; CAT, catalase; MDA, malondialdehyde; NAC, N-Acetylcysteine; Pifithrin-α, p53 inhibitor. SOD, superoxide dismutase; T-AOC, total antioxidant capacity.

Figure 4. The effects of cigarette smoke on oxidative stress indicators in mice. * P < 0.05 versus the control group; # P < 0.05 versus the CS + Pifithrin-α group; ※ P < 0.05 versus the CS+NAC group; ▲ P < 0.05 versus the control group; & P < 0.05 versus the CS + NAC group. N = 8 mice per group. Values are expressed as mean ± standard deviation. CS, cigarette smoke; CAT, catalase; MDA, malondialdehyde; NAC, N-Acetylcysteine; Pifithrin-α, p53 inhibitor; SOD, superoxide dismutase; T-AOC, total antioxidant capacity.

Figure 5. The effects of cigarette smoke on protein expression in mice. * P < 0.05 versus the control group; # P < 0.05 versus the CS + Pifithrin-α group; & P < 0.05 versus the CS + NAC group. N = 8 mice per group. Values are expressed as means ± standard deviation. CS, cigarette smoke; NAC, N-Acetylcysteine; Pifithrin-α, p53 inhibitor.