Exercise pretraining protects against cerebral ischaemia induced by heat stroke in rats.

Abstract

BACKGROUND:

In the rat brain, heat-stroke-induced damage to cerebral neurons is attenuated through heat-shock-induced overexpression of heat-shock protein 72 (HSP72).

OBJECTIVE:

To ascertain whether progressive exercise preconditioning induces HSP72 expression in the rat brain and prevents heat-stroke-induced cerebral ischaemia and injury.

METHODS:

Male Wistar rats were randomly assigned to either a sedentary group or an exercise group. Those in the exercise group progressively ran on a treadmill 5 days/week, for 30-60 min/day at an intensity of 20-30 m/min for 3 weeks. The effects of heat stroke on mean arterial pressure, cerebral blood flow, brain ischaemia markers (glutamate, lactate/pyruvate ratio and nitric oxide), a cerebral injury marker (glycerol) and brain neuronal damage score in the preconditioned animals were compared with effects in unexercised controls. Heat stroke was induced by exposing urethane-anaesthetised animals to a temperature of 43 degrees C for 55 min, which caused the body temperature to reach 42 degrees C.

RESULTS:

Three weeks of progressive exercise pretreatment induced HSP72 preconditioning in the brain and conferred significant protection against heat-stroke-induced hyperthermia, arterial hypotension, cerebral ischaemia and neuronal damage; it also prolonged survival.

CONCLUSIONS:

Exercise for 3 weeks can improve heat tolerance as well as attenuate heat-stroke-induced cerebral ischaemia in rats. The maintenance of mean arterial pressure and cerebral blood flow at appropriate levels in the rat brain may be related to overexpression of HSP72.

• Authors: Yu-Wen Chen, Sheng-Hsien Chen, Willy Chou, Yi-Ming Lo, Ching-Hsia Hung, Mao-Tsun Lin
• Journal: British journal of sports medicine (Br J Sports Med) Vol. 41 Issue 9 Pg. 597-602 (Sep 2007) ISSN: 1473-0480 [Electronic] England
• PMID: 17496074 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• HSP72 Heat-Shock Proteins

Topics

• Animals
• Blotting, Western
• Body Temperature (physiology)
• Brain Ischemia (prevention & control)
• Cerebrovascular Circulation (physiology)
• HSP72 Heat-Shock Proteins (metabolism)
• Heart Rate (physiology)
• Heat Stroke (etiology, physiopathology)
• Male
• Neurons (pathology)
• Physical Conditioning, Animal (physiology)
• Random Allocation
• Rats
• Rats, Wistar