Effects of various exhaustive exercise on hepatic apoptosis in rats

Tiefu CHEN; Shanni LI

ABSTRACT

BACKGROUND:

Previous studies demonstrated that exercise modes easily cause hepatic injury and result in hepatic apoptosis. However, the mechanisms remain undear.

OBJECTIVE:

To observe the hepatic apoptosis, changes of hepatic glycogen, NO, and calcium levels following establishing various exhaustive exercise models.DESIGN, TIME AND

SETTING:

The randomized, controlled, animal experiment of ultrastructure observation was performed at the Physical Education School of Hunan Normal University, and Department of Histology and Embryology, Central South University, from January 2004 to December 2006.MATERIALS Thirty male Sprague Dawley rats, aged 8 weeks, weighing (219.2+19.5) g, were randomly divided into control, middle intensity exercise and high intensity exercise groups according to Berdford models, with 10 animals in each group.

METHODS:

Rats in the exercise group were performed 3 days treadmill training with speed of 10 m/min, in running platform with 0°, followed by 3 days rest. After that, rats in the middle intensity exercise group were training with initial velocity of 10 m/min for 12 minutes, and than gradually increased exercise load to 19.3 m/min, until rats were exhausted. In the high intensity exercise groups,the initial velocity was 26.8 m/min, until rats were exhausted. The training was performed once per day for 30 successive days.There was no exercise training in the control group.MAIN OUTCOME

MEASURES:

The levels of hepatic glycogen, NO, Ca~(2+), and hepatic apoptosis were measured after exercise.

RESULTS:

Totally 30 rats were included in the final analysis. All rats finished exercise without resistance. The exhaustive exercise time in the middle intensity exercise group was (234.60+60.05) min, which was (92.40±34.61) min in the high intensity exercise group. Compared to the control group, the contents of hepatic glycogen and NO were decreased, while Ca~(2+) level and hepatic apoptosis index were increased in 2 exercise groups (P < 0.05, P < 0.01 ), in particular notable in the middle intensity exercise group (P < 0.05).

CONCLUSION:

Both middle and high intensity exhaustive exercise can lead to hepatic apoptosis, which may be the great accumulation of Ca~(2+) in mitochondrion and the fower contents of liver glycogen and NO content. The changes may be associated with exhaustive exercise time.