| Background And Objective With the wide application of high and new technology and the development of warship equipment, various strong equipment has been widely used and chances to be exposed to the magnetic fields have increased. Warship magnetic field is a strong magnetic environment and the intensity is about hundreds or thousands times stronger than that of the geomagnetism (usually about 0.05ml) . Now electromagnetic mine sweeping facilities in the mine sweepers are the main magnetic sources, with strong magnetic field spreading all over every cabin and naval vessel. As a result, the crew expose themselves entirely to the strong magnetic field during their training or staying in mine sweeping. Based on the test concerning about magnetic field in mine dredger of our country, the main cabin has the highest magnetic intensity , which is around 50-150mT. while in the dwelling cabin and other places where people constant stay, the magnetic intensity is about 1~10mT. In addition, the nuclear reactor in nuclear-powered naval ship can also produce magnetic field of certain intensity. People in theneighborhood are likely to expose themselves to the magnetic field with the intensity of 7~45mT. Meanwhile the magnetic-powered ships and electromagnetic ships, which are just in developing, all can produce even stronger magnetic field which will bring new magnetic pollution to warship. Recent studies have showed that the bio-effective strength of magnetic field is determined by both its intensity and exposing time. High intensity together with long-term low intensity exposure can cause the same strong biologic effect. Magnetic field can do negative influence on neural system. Vojtisek et al have reported when Wistar rats expose themselves to magnetic field by 10mT 50Hz for one hour, the latency of Visual Evoked Potentials (VHP) shows that the tendency reduced, but there is no statistical significance. The visual system has important function of light and imaging perception. The effects of high intensity magnetic field are not well known.Objective: 1. To explored the influences on retinal function of golden hamsters by observing the variation of dopamine concentration in their retina when they are exposed to the simulated strong magnetic fields. 2. Experimental rabbits are chosen to observe the latency and attitude change of VEP by simulating them with strong magnetic exposure.Methods While simulating the intensity , type and exposing time of magnetic field which will be faced with the shipmen in mine dredger, the chosen animals were exposed to the above magnetic environment. Since that dopamine mainly affects the function of rod pathway, the golden hamster with rod cell dominant and fully pigment epithelium retina are chosen as the experimental animal. New Zealand rabbits are chosen to observe the latency and attitude change of VEP.Thirty-six mature male golden hamsters and twenty-four New Zealandbig rabbits were at random divided into four groups which were subdivided into four groups, and each group had nine golden hamsters and seven rabbits. Then four groups were subdivided into three 0.1 HZ alternate magnetic field exposing groups and one control group(namely 1st, 2nd, 3rd and contyol group respectively). Animals in exposing groups were completely exposed to the magnetic environment , the intensity of which was 50mT (1st group), 75mT (2nd group), 100mT (3rd group) and 0.05ml (0 group), respectively. The animals were exposed eight hours a day for seven consecutive days, meanwhile animals in control group were put in mimetic pseudo magnetic environment synchronized with experimental groups. The experimental temperature is 25 2 C, relative humidity is about 70% å¤ 10%.1 Experimental animals as well as controlled ones were executed immediately after seven days' exposure, and eyes were removed and frozen in liquid nitrogen. Tn ice bath, the retinal was peeled off under a dissecting microscope and weighed, then added 100ul extracting fluid to form evenly plasm, centrifuged fo...
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