Table 1.

Markers of cardiac injury

Treatment	GT	TUNEL	proMMP-2	β-GUase	ANP mRNA
Control	+/+	0.22  ± 0.02 (6)	1.80  ± 0.10 (7)170	0.19  ± 0.02 (7)	2.27  ± 0.46 (7)
Control	−/−	0.24  ± 0.09 (7)*	1.30  ± 0.06 (7)***	0.22  ± 0.01 (7)**	2.67  ± 0.55 (7)
Exercised	+/+	0.24  ± 0.02 (10)	1.86  ± 0.06 (11)	0.22  ± 0.02 (11)	2.32  ± 0.32 (11)
Exercised	−/−	0.72  ± 0.25 (11)†	1.87  ± 0.09 (10)	0.35  ± 0.05 (10)‡‡	3.63  ± 0.78 (11)

Average number of TUNEL-positive nuclei in a 40× objective (TUNEL), activity of proMMP-2 (densitometric unit), activity of β-glucuronidase (β-GUase, μmol s⁻¹⋅kg⁻¹ protein), and ANP mRNA levels (to 18S mRNA) in the left ventricles of unexercised controls and exercised mice 48 h after the cessation of running. Values are means ± SEM, with n indicated in parentheses. Statistical significances in the Mann–Whitney U test: between the control^−/− and exercised^−/− mice. *, P < 0.05, **, P < 0.025, ***, P < 0.001; those between the exercised^+/+ and exercised^−/− mice.  

^†, P < 0.025,  

^‡‡, P < 0.01; and those between the control^+/+ and control^−/− mice.  

¹⁷⁰, P < 0.001.