Objective: To observe the effects of preventative moxibustion on adenosine monophosphate-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) in myocardial tissue in rats with exhaustive exercise, and to explore the action mechanism of preventative moxibustion for myocardial injury by exhaustive exercise.
Methods: Eighteen SD male rats were randomly divided into a blank group, an exhaustive exercise group and a moxibustion group, 6 rats in each one. Rats in the blank group were treated with immobilization for 5 min per day, without any intervention. Rats in the exhaustive exercise group were treated with no intervention in the first 10 days. Rats in the moxibustion group were treated with moxibustion at "Zusanli" (ST 36) and "Guanyuan" (CV 4), 5 cones for each acupoint, for 10 days.On 11th day, rats in the exhaustive exercise group and moxibustion group were sacrificed to collect sample after exhaustive swimming, and time of exhaustive exercise was recorded. HE staining was used to observe the inflammatory changes of myocardial tissue; colorimetric method was used to measure lactic dehydrogenase (LDH), activity of superoxide dismutase (SOD) and malonaldehyde (MDA); immune suppression method was used to measure the content of creatine kinase isoenzyme (CK-MB) in serum; Elisa method was used to measure the content of troponinT (cTnT) in serum; western blot method was applied to measure the content of AMPKα2 and mTOR in myocardial tissue.
Results: The time of exhaustive exercise was (4 831.17±689.88) s in the moxibustion group, which was longer than (3 509.50±1 232.49) s in the exhaustive exercise group (P<0.05); HE staining indicated structure of the myocardium was clear and inflammatory cell infiltration was reduced in the moxibustion group. Compared with the blank group, the contents of serum LDH, CK-MB, cTnT were increased in the exhaustive exercise group (all P<0.05); MDA content was increased and SOD activity was decreased (both P<0.05); the AMPK α2 content in myocardial tissue was increased and the mTOR content was decreased (both P<0.05). Compared with the exhaustive exercise group, the contents of serum LDH, CK-MB, cTnT were reduced in the moxibustion group (all P<0.05); MDA content was decreased and SOD activity was increased (both P<0.05); the AMPKα2 content in myocardial tissue was increased, and the mTOR content was decreased (both P<0.05); AMPKα2 and mTOR were negatively correlated (r=-0.764, P<0.05).
Conclusions: Preventative moxibustion is likely to regulate the expression of AMPK and mTOR to induce signaling pathway to recover myocardial injury by exhaustive exercise.
Keywords: adenosine monophosphate-activated protein kinase (AMPK); exhaustive exercise; mammalian target of rapamycin (mTOR); myocardial injury; preventative moxibustion.