贻贝棘尾虫年轻与衰老无性系抗氧化能力的比较

COMPARISON OF THE ANTIOXIDATIVE CAPACITIES BETWEEN YOUNG CLONE AND AGED CLONE OF STYLONYCHIA MYTILUS

贻贝棘尾虫采自黑龙江省帽儿山南山水库附近水塘，于1995年9月在本系实验室通过接合生殖得到的接合后体，克隆培养作为年轻无性系；采用1988年9月以来实验室保存培养的去小核无性系为衰老无性系。测定了在相同条件下培养的贻贝棘尾虫年轻（约200代分裂）和衰老（约2000代分裂）无性系消除02和·OH的能力、脂质过氧化程度及脂褐素含量。结果表明，贻贝棘尾虫年轻无性系消除02和·OH的能力（P＜0．01）显著高于衰老无性系，脂质过氧化程度（p＜0.001）和脂褐素含量（p＜0．001）显著低于衰老无性系，即年轻无性系抗氧化能力显著高于衰老无性系。

The Stylonychia mytilus was collected from Maoershan Hill in Heilongjiang Province.The clone which is raised from a new cell after conjugation in lab in September 1995 is used asthe young group; the clone which has been ndsed in lab from September 1988 without micronucleusin cell is used as the aged one. Both groups are syngen with the same hereditary condihon, so theycan be compared. The young clone reached 200 fissions, and the aged one obtaln 2 000 fissions atthe time of experiment according to the demands of experimenL In order to obtain the difference inthe anhoxidahve capacity of the young and the aped S.mytilus, the capacities of scavenging thesuperoxide free radical (O2 ) and the hydroxyl radical( OH), the level of lipid peroxidation andthe contents of lipofusion are determined of the young S mytilus and the aged S mytilus in thisstudy. The results show that the capacities of scavenging free O2 radical and free OH radical(p < 0.01) of the young S mytilus are evidently higher than those of the aged ones and the levelof lipid peroxidation (p < 0.001) and the content of lipofusion (p < 0.001) are evidenhy lower forthe young S mytilus than those for the aged, the antioxidative capacity of the aged S mytilus issignificanhy lower than that of the young one. According to the free radical theory of agingadvanced by Harman (1956, 1962, 1968, 1981), the aging is the result of a Poisonous effect of thefree radicals produced during the cell metabolism. The poisonous effect of the free radicals in celland the lipid peroxidating accelerates cell aging; however, the cell has an antioxidative system toreduce the harm. The system includes enzymes such as SOD, GSH-POD CAT, and nonenzymeantioxidants such as VE' Uric acid, VC β-carotene, GSH and the DNA repair system. The results inthes paper are in accord with the conclusions that the free radical theory of aging is applicable notoniy to the higher muticellular animals but also to the single cell protozoa showing that thereduchon of the antioxidative capacity is one of the most important reasons for the cell aging interm of cell fission number as the fission increases.