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AIM: To investigate the effect oferythropoietin (EPO) on the rats with heart failure (HF) in hypothermia and to explore its underlying mechanism.METHODS: The Sprague-Dawley rats (n=80) were randomly divided into five groups: control group (CON group), HF in low-temperature group (HFLT group), HF in normal temperature group (HFNT group), HF with EPO in low temperature group (HFLT+EPO group), and HF with EPO and LY2940002 in low temperature group (HFLT+EPO+LY group).All rats were housed in artifitial climate chamber.The animals in CON, HFLT, HFLT+EPO and HFLT+EPO+LY groups were under the low-temperature environment, while those in HFNT group were under normal temperature.The heart function was evaluated by echocardiography.The rats were then executed and the hearts were harvested.The apoptosis of myocytes was assessed by TUNEL method.The mRNA expression of Fas and PI3K was detected by fluorescence quantitative PCR (qPCR) and the protein levels of HSP70, Akt and p-Akt in the myocardial tissues were determined by Western blot.RESULTS: The rat cardiac functions in HFLT group were significantly deteriorated compared with HFNT group.The cardiac functions in HFLT+EPO group were improved compared with HFLT group.The cardiac functions in HFLT+EPO+LY group were significantly pejorated compared with HFLT+EPO group.The apoptotic index of the myocardium in HFLT group and HFNT group was significantly higher than that in CON group (P<0.01).The apoptotic index of the myocardium in HFLT group was significantly higher than that in HFNT group (P<0.05).The apoptotic index of the myocardium in HFLT+EPO group was significantly lower than that in HFLT group (P<0.01).The mRNA expression of Fas in HFLT group was significantly higher than that in HFNT group, and no obvious difference of the mRNA expression level of PI3K between HFLT group and HFNT group was observed.The mRNA expression of PI3K in HFLT+EPO group was significantly lower than that in HFLT group and HFLT+EPO+LY group (P<0.05), and that in HFLT+EPO group was significantly higher than that in HFLT group and HFLT+EPO+LY group (P<0.05).The protein levels of p-Akt and HSP70 in HFLT+EPO group was also higher than those in HFLT group and HFLT+EPO+LY group (P<0.05), and no obvious difference of the protein levels of p-Akt and HSP70 in CON, HFLT and HFNT groups was found.The protein level of Akt had no significant difference in each group.CONCLUSION: The pathway of PI3K/Akt may be one of the cardioprotective ways of EPO.EPO activates the PI3K/Akt pathway, upregulates the experssion of HSP70 (an endogenous protective factor) and inhibits the apoptosis, thus protecting the cardiac functions in the rats with HF in hypothermia.
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Objective To observe the effect of low level infrasound on neuropathic pain and explore its underlying mechanism. Methods Rats were divided into experimental and control groups after their L5 spinal nerves had been ligated to create a neuropathic pain model. The experimental group was subjected to 40 to 80 dB infra sound. The control group received no infrasound treatment. Paw withdrawal latency in response to heat radiation was measured and the average gray scale of the microglia in a slice of the L5 spinal cord was compared. Results The experimental group expressed significantly lengthened paw withdrawal latency on the 12th and 14th day. The average gray scale showed significantly weakened activation of spinal microglia in the 2nd week of infrasound treatment compared with the control group. Conclusion Low level infrasound can ameliorate neuropathic pain to a certain extent,which might be related with inhibition of spinal microglia.
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@#ObjectiveTo study the effect of 8 Hz infrasound on the expression of 5-hydroxytryptamine (5-HT) in rats' hippocampus and temporal cortex.Methods140 male SD rats were randomly divided into the control group, and experimental groups that exposed to infrasound of 8Hz,90dB,100dB and 130dB for 1,7,14,21,28,35,42 days. Experimental groups were exposed to infrasound for 2 hours each day. The control group was only placed in the infrasonic storehouse but without infrasound. Rats' brains were taken as soon as the exposure finished and strained by immunohistochemistry. The content of 5-HT in hippocampus and temporal cortex was detected under an optical microscope.ResultsInfrasound groups had less expression of 5-HT in hippocampus and temporal cortex than the control group (P<0.01), and the least were at the 28th day for 90 dB and 100 dB groups and the 21st day for 130 dB group. Then the expression of 5-HT had an increase in each group.ConclusionThe deceased expression of 5-HT in rats' hippocampus and temporal cortex could result from infrasound of 8 Hz. Rules of change are related to the parameter of infrasound and the 130 dB 8 Hz infrasound can induce greater changes compared with that of 100 dB and 90 dB.
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Objective To observe the effects of infrasound on rat myocardial cells and to study its underlying mechanism. Methods One hundred Sprague-Dawley rats were divided into a normal control group and a infrasound exposure group, composed of various subgroups subject to exposure to infrasound for 2 hours daily for 1 d,7 d,14 d,21 d,and 28 d, respectively. The ultra-microstructure and apoptosis of the rat myocardial cells were observed, and SOD and MDA were measured. Results After exposure to infrasound, significant ultra-microstructural impairment and increased apoptosis of the myocardial cells were observed in the infrasound exposure group as compared to those of the normal control group,(P
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AIM: To observe the changes of NO, ET-1, SOD and MDA levels in plasma of rats exposed to infrasound. METHODS: Using infrasound (frequency: 8 Hz; sound pressure level:130 dB), the rats were exposed for 1 d, 7 d, 14 d, 21 d and 28 d, 2 h daily, then the levels of NO, ET-1, SOD and MDA were measured after exposure. RESULTS: The changes of NO levels in plasma significantly declined at 7 d and 14 d (P0.05). The changes of ET-1 levels in all groups in plasma were significantly increased (P
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AIM:To observe the effects of infrasound on sperm quality and explore some underlying mechanisms. METHODS: Adult male SD rats were exposed to infrasound of 8 Hz at 90 dB or 130 dB for 1,7,14 or 21 d(2 h/d), whose epididymises were obtained for sperm count, abnormity and activity ratio inspection and whose testes for GSH-Px and MDA inspection. RESULTS: With prolonged exposure, sperm quality and GSH-Px in 90 dB and 130 dB groups decreased, while MDA increased, and at the same time point, the indexes of 130 dB groups changed more profoundly than those in 90 dB groups. CONCLUSION: Biological effect of infrasound on testes depends on the exposure parameters. The mechanisms of which could be unbalanced antioxidant system induced by infrasonic exposure.