Cr^6+暴露对红树蚬卵巢中氧化应激和生殖基因表达的影响

Effects of Cr 6+Exposure on Oxidative Stress and Reproductive Gene Expression in the Ovaries of Polymesoda erosa.

Cr^6+具有较强的氧化能力,通常能够造成生物体脂质过氧化胁迫。为探究Cr^6+暴露对红树蚬(Polymesoda erosa)卵巢的生殖毒性效应,共设置ρ(Cr^6+)为0、0.25、1、4和8 mg·L^-15个浓度梯度,暴露时间为0、5、10和15 d。结果表明,Cr^6+对红树蚬卵巢造成氧化胁迫,并影响卵巢雌激素受体er基因和卵黄原蛋白vtg基因表达量。与对照相比,高浓度Cr^6+胁迫使红树蚬性腺指数(GSI)显著降低(P<0.05),且随着Cr^6+浓度升高和试验时间增加,GSI下降程度越明显。高浓度Cr^6+处理红树蚬vtg和er基因表达量显著低于低浓度处理和对照(P<0.05)。此外,通过氧化应激试验发现,经低浓度Cr^6+胁迫后,红树蚬卵巢过氧化氢酶(CAT)和谷胱甘肽转移酶(GST)活性以及丙二醛(MDA)含量在10 d后与对照相比无显著差异(P>0.05);而与对照相比,高浓度Cr^6+处理CAT和GST活性被显著抑制(P<0.05),MDA含量也明显升高。Cr^6+对红树蚬卵巢具有组织损伤和代谢干扰效应,并且高浓度Cr^6+对红树蚬生殖存在明显毒害作用。

Cr^6+can usually cause lipid peroxidation stress in organisms due to its strong oxidative capacity.In this study,the reproductive toxicity of Cr^6+exposure on female Polymesoda erosa was investigated.Five concentration groups of Cr^6+were set as 0,0.25,1,4 and 8 mg·L^-1 and the exposure time of each concentration group was set as 0,5,10 and 15 d.The results indicate that the exposure to Cr^6+could cause oxidative stress on the ovaries of Polymesoda erosa and change the expression of er(estrogen receptor gene)and vtg(vitellogenin gene).Compared with control group,the high concentration of Cr^6+treatment groups could significantly reduce the gonadosomatic index(GSI)of Polymesoda erosa(P<0.05).Moreover,the GSI varied significantly with the increase of Cr^6+concentration as time goes by.The expression of vtg and er in high concentration treatment group was significantly lower than that in low concentration treatment group as well as control group(P<0.05).In addition,it was found that the activities of CAT,GST and MDA content in ovaries would get back to normal level(P>0.05)after exposing to low concentration of Cr^6+.On the other hand,high concentration of Cr^6+exposure would eventually inhibit the activities of both enzymes(P<0.05)and increase the content of MDA significantly.The results manifest that Cr^6+has tissue damage and metabolic disturbance effects on the ovaries of Polymesoda erosa and high concentration of Cr^6+would cause obvious toxic effects on the reproduction of Polymesoda erosa.