Effects Of The Upper Yellow River Pollution On Survival And Oxidative Stress Of The Bufo Raddei

Environmental pollution is becoming a world widely worried problem with the fast development of industry and the population explosion. Many reports had focused on negative effects of pollutants which contributing on amphibian declination. The physiological stress of the environmental pollutants could be detected by measuring antioxidant system changes based on oxidative damage mechanism. A sensitive evaluation about extent of environmental pollution and its bio-risk could also be obtained through these biomarkers.The present research concentrated the work on two aspects: 1) Population investigation of the toad Bufo raddei was carrying out in the toad's breeding season at Lanzhou(LZ), a badly polluted area and Liujiaxia(LJX) Reservoir which located at the upstream 75Km southwest to Lanzhou, a relative unpolluted area. 2) Comparison of antioxidant enzymes activities such as SOD, CAT, GPx as well as contents of GSH and MDA of adult B. raddei sampled from LZ and LJX were measured in April, June and August. Some conclusions were made from results.Comparing about population characters between LZ and LJX shows a higher sex ratio and low average body weight and length of B. raddei from LZ than those from LJX. Furthermore, the correlation of the body weight and length was varying in two areas.Average body weight and length of adult B. raddei sampled from LZ during April, June, August was lower than those sampled from LJX. The population discrepancy confirmed the physiological declination of B. raddei in LZ.SOD activity in liver and kidney of B. raddei in LZ was significantly higher in April together with male hepatic SOD activity in June and renal SOD activity in August. However female SOD activity in both organs was lower in LZ thanthose in LJX during August. Enzyme discrimination between two areas supposed an up-down floating under polluted environment with seasonal change and varied by the organ and sex.All hepatic CAT activities of B. raddei in I_Z were lower than those in LJX excepted in August male individuals. Renal CAT activities in two sites have no significant difference but male activity increase in LZ in August. The results of comparing showed environmental pollution inhibited CAT activity mostly in liver.Female hepatic GPx activity in LZ was higher than that in LJX with renal enzyme decreasing in April. All GPx activities of the toads from LZ during June were lower than those from LJX except for male enzyme activity in kidney and significantly increased in August excluding female renal GPx activity. It's appeared that GPx activity of the B. raddei under polluted condition was inhibited before being induced in both liver and kidney.From April to August, the fluctuating of comparison of the GSH content in liver of the B. raddei between two areas was such complicated as a down-up-down alternating in male contrasting to average-down-up change in female. Most renal GSH contends of the B. raddei in LZ were higher than those in LJX, which indicated renal GSH in B. raddei was induced by the pollutants.MDA contents, a lipid peroxide index in two organs of B. raddei from LZ were higher than those from LJX in April and June which indicating higher lipid per oxidized level under polluted environment. MDA content in August was decreased at both areas accompany MDA depression in LZ respecting to that in LJX.It is concluded from the research that using antioxidant enzyme system's change of the amphibian as the biomarker to monitor environmental pollutionis feasible. Furthermore, the characters of different kinds of antioxidant enzymes and their patterns with space-time change in two sexes need to be further studied in order to evaluate environmental pollution more acutely.