Experimental Study On Protection Effects Of Curcumin On Infrasonic Brain Damage

Infrasound has been ranked as a novel soft killing technology and has attracted much attention for its bioeffects. It has been confirmed that animals exposed to high intensity infrasound may result in damages of nervous system, auditory system, cardiovascular system, respiratory system, digestive system, pituitary-adrenalin system etc, especially infrasound causes function disorder and structure injury of central nervous system (CNS) and thus affects work and study greatly. Because infrasound exists in natural and man-made environment broadly and the general acoustic screen can not shield it, research on medicament protection from damage of it has much significance. Study has testified that infrasonic brain damage is related to free radical accumulation and peroxidation in brain cortex. It has been conformed that oxidation-antioxidation banlance loses and lipofuscin accumulates in the neurons of brain cortex of mice after infrasound exposure. So we select Curcumin(Cur) —a kind of antioxidant as a potential medicament for infrasound damage protection and experimentize. In this study, memory function , oxidation- antioxidation banlance , ultra — structure of frontal lobe of brain cortex of the mice and the effects of curcumin for that were observed after infrasound exposure.AIMFirst, to investigate the brain damage effects of infrasound of two diffrent frequency and contrast with each other; Second, to observe the effects of different doses of Curcumin for changes of memory function, oxidation-antioxidation balance, ultrastruture of the frontal lobe of brain cortex of the mice after infrasound exposure and probe into the mechanism of it; And third, affirm a reasonable medicament method and offer a safe, efficient dose or dose range.METHODS1. Parameter of infrasound: 8Hz/16Hz, 130dB, 2h/d, 7d/14d; 2.Method of medication: Preventive administration (take Cur before infrasound exposure lw), Therapeutic administration (take Cur after each infrasound exposure lh). Infrasound exposure time was 7d in the experiment of preventive administration and 14d in the experiment of therapeutic administration; 3. Grouping: set bare control group , pute infrasound group , infrasound+Cur low (40mg/Kg/d) , middle (80mg/Kg/d) , high (160mg/Kg/d) dose group. ①Evaluate memory function by delitescence-the time in which the mice reach the flat in Morris round maze; (2) Observe the changesof SOD, GSH-Px and MDA in brain cortex of the mice after pute infrasound and infrasound+Cur treating; (3) Observe the changes of the ultrastruture of frontal lobe of brain cortex by transmission electron microscope (TEM) . RESULTS1. Changs of memory function of the mice and the influence of Cur.(1) Preventive administration: After infrasound exposure for 7d(2h/d), delitescence of the mice had no apparente difference between pute infrasound group and bare control group (P>0. 05) ;and the same between pute infrasound group and each infrasound+Cur group (P>0. 05) .(2) Therapeutic administration: After infrasound exposure for 14d(2h/d), delitescence of pute infrasound group mice was prolonged than bare control group mice(P < 0.05) ; delitescence of each infrasound+Cur group mice was shortened than pute infrasound group mice and there was significance between infrasound+Cur middle, high dose group and pute infrasound group(P<0. 05).2. Changes of oxidation-antioxidation balance in frontal lobe of brain cortex of mice and the influence of Cur.(1) Preventive administration:Part of experiment of 16Hz: Compared with bare control group mice, GSH-Px and MDA of pute infrasound group mice increased(P <0. 05), SOD had no obvious changes (P>0. 05) . Compared with pute infrasound group mice, GSH-Px and MDA dereased in infrasound+Curmiddle and high dose group mice(P<0. 05), SOD had no obvious changs (P>0.05) .Part of experiment of 8Hz: Compared with bare control group mice, activity of GSH-Px and SOD of pute infrasound group mice decreased, MDA increased(P<0. 05). Compared with pute infrasound group mice, SOD, GSH-Px and MDA had no obvious changes in infrasound + Cur low dose group (P>0.05) ;GSH-Px and SOD increased, MDA decreased in infrasound+ Cur middle and high dose group mice(P <0. 05).Dose-effect relationship was found in effects of Cur of preventive administration.(2) Therapeutical administration:Part of experiment of 16Hz: Compared with bare control group mice, GSH-Px and MDA of pute infrasound group mice increased(P <0. 05),SOD had no obvious changes (P>0. 05) . Compared with pute infrasound group mice, GSH-Px decreased, SOD increased in infrasound+Cur middle and high dose group mice(P < 0.05);MDA decreased in all infrasound+Cur group mice(P<0. 05).Part of experiment of 8Hz: Compared with bare control group mice, activity of GSH-Px and SOD of pute infrasound group mice decreased, MDA increased(P<0. 05). Compared with pute infrasound group mice, GSH-Px increased, MDA decreased in all infrasound+Cur group mice(P<0. 05) ;SOD increased in infrasound+Cur middle andhigh dose group mice (P<0. 05).Dose-effect relationship was found in effects of Cur oftherapeutical administration in certain dose range.3. Changs of ultrastructure of frontal lobe of brain cortex of the mice and the protection effects of Cur.(1) Preventive administration:Ultrastructure of frontal lobe of brain cortex showed some changes after 8Hz/16Hz infrasound exposure for 7d (2h/d) , neurons showed anoxic character and taking high dose of Cur preventively cound lighten this phenomenon.Part of experiment of 16Hz: Microglia were found around neurons, capillary vessels were edematous and Myelin denaturalized after 16Hz infrasound exposure for 7d (2h/d) . High dose of Cur preventively might protect neurons by affecting activities of Microglia. Taking Cur preventively had no obvious protection for capillary vessels and Myelin.Part of experiment of 8Hz: Lipofuscin increased in cytoplast, mitochondria swelled or formed vacuole and capillary vessels were edematous after 8Hz infrasound exposure for 7d (2h/d) . Taking middle or high dose of Cur preventively lightened the accumulation of lipofuscin and mitochondria damage. Taking Cur preventively had no obvious protection for capillary vessels.(2) Therapeutical administration: Ultrastructure of frontal lobe of brain cortex showed obvious changes after 8Hz/16Hz infrasound exposure for 14d (2h/d). Neurons showed denaturalization character.Part of experiment of 16Hz: Lipofuscin increased heavenly in neuron cytoplast, capillary vessels were edematous and Myelindenaturalized, taking Cur remedially reduced or even cleared accumulation of lipofuscin but had no obvious effects for capillary vessels and Myelin.Part of experiment of 8Hz: Lipofuscin also increased in neuron cytoplast, mitochontria swelled, malformed obviously and generally, capillary vessels were edematous, taking Cur remedially reduced accumulation of lipofuscin and lightened or even cleared damage of mitochondria. Taking Cur remedially had no obvious effects forcapillary vessels. CONCLUSION1. Damage effects of infrasound were related to its frequcency. Memory function of mice decreased and MDA increased in mice brain after 8Hz/16Hz infrasound exposure for 14d(2h/d), but change trends of SOD, GSH-Px were not consistent. See from ultrastructure changes of the brain cortex, damage effects of 16Hz infrasound focused on lipofuscin accumulation in cytoplast, capillary vessels edema and Myelin denaturalization. Besides lipofuscin accumulation in cytoplast, damage effects of 8Hz infrasound were characteristic of mitochondria damage, while capillary vessels edema and Myelin denaturalization were slight relatively.2. Taking Cur remedially ameliorated memory function of the mice, adjusted oxidation-antioxidation banlance of brain and lightened or cleared 8Hz/16Hz infrasonic lipofuscin accumulation and 8Hz infrasonic damage of mitochondria in cytoplast,but had little effects for 8Hz/16Hz infrasonic capillary vessels edema...