PCO模型大鼠卵巢组织氧化应激水平的研究

Study on the Oxidative Stress in the Ovaries of a Rat Model of Polycystic Ovary

目的应用来曲唑建立多囊卵巢（PCO）大鼠模型,从组织及细胞水平测定模型大鼠卵巢氧化应激状态,探讨卵巢氧化应激在多囊卵巢综合征（PCOS）发病中的作用,为PCOS治疗提供新的思路。方法将6周龄清洁级雌性SD大鼠,随机编为实验组〔45只,予1%羧甲基纤维素溶液1mL/d＋来曲唑1mg/（kg·d）灌胃〕和对照组（45只,仅予1%羧甲基纤维素溶液1mL/d灌胃）,均持续28d。每日定时行阴道细胞涂片巴氏染色镜检,判断动情周期,每7d测量体质量了解生长情况,第29d两组大鼠统一处死、采血。测量指标：血清雌二醇（E2）、孕酮（P）、促卵泡刺激素（FSH）、促黄体生成素（LH）、睾酮（T）、性激素结合蛋白（SHBG）,计算游离雄激素指数（FAI）;解剖子宫、卵巢,称重后计算器官质量指数;所得两侧卵巢,一侧固定后石蜡切片HE染色,另一侧制备组织匀浆、单细胞悬液,测定组织匀浆总氧化态（TOS）、总抗氧化态（TAS）、脂质过氧化物丙二醛（MDA）含量、超氧化物歧化酶（SOD）活力;检测卵巢单细胞悬液细胞内活性氧（ROS）水平。通过比较两组大鼠上述指标的差异,验证造模是否成功,分析卵巢组织氧化应激水平与PCOS的关系。结果 1实验组用药12~15d后动情周期消失,体质量增长明显超过对照组（P〈0.05）;2实验组性激素改变符合人类PCOS特征;3实验组卵巢质量、卵巢指数大于对照组（P〈0.05）,子宫质量、子宫指数小于对照组（P〈0.05）;4相对对照组大鼠,实验组大鼠卵巢HE切片镜下表现为卵泡数量增多、白膜增厚、颗粒细胞层变薄、间质增生等改变;5实验组大鼠卵巢组织内MDA含量、TOS、氧化应激指数（OSI）高于对照组,SOD活力、TAS低于对照组（P〈0.05）;细胞内ROS水平高于对照组（P均〈0.05）。结论1应用来曲唑可成功诱导大鼠PCO模型,适于研究卵巢病变。2本方法所制备的PCO模型卵巢处于明显的氧化应激状态,存在细胞氧化损伤,推测人类PCOS卵巢组织内可能也存在氧化应激,因此对于PCOS的处理,在常规药物治疗同时,应注重抗氧化治疗。

Objective To establish a pathological animal model of polycystic ovary（PCO）by letrozole in rats.Investigate whether PCO were mediated by the effect of oxidative stress by measuring oxidative stress levels in this cohort of rats with PCO,and proceed a new way of treatment for polycystic ovary syndrom（PCOS）.Methods90 SD female rats aged 6weeks were randomly divided into two groups,including a control group of 45 rats that received vehicle only 〔1% aqueous solution of carboxmethlycellulose（CMC）,1 mL/d〕once daily orally（p.o.）,and an experimental group of 45 rats,which were administered letrozole at concentrations of 1mg/kg p.o.dissolved in 1% CMC（1mL/d）once daily.The treatment period was 28 d.During this period,vaginal smears were collected daily for estrus cycle determination and body masses were measured every 7d.On the day subsequent to the last letrozole dose administration,rats were killed;Uteri and ovaries were then excised and weighed for the calculation of organ indexes.Serum hormone levels,SHBG and histologic changes in the ovaries were examined.Then testosterone free index（FAI）was calculated.Oxidant status was evaluated by determination of ovarian total oxidant status（TOS）,malondialdehyde（MDA）concentration and intracellular reactive oxygen species（ROS）level,while antioxidant status was evaluated by determination of total antioxidant status（TAS）and superoxide dismutase（SOD）concentration.Results Vaginal smear test showed the estrus cycle began to disappear from day 12 to day15.A statistically significant difference in growth curves,ovarian weights,uterine weights and organ indexes between the groups were also observed.In rats with PCO serum testosterone（T）,follicle-stimulating hormone（FSH）concentrations and free androgen index（FAI）were significantly increased compared with the control group（rats without PCO）.However,rats with PCO had decreased levels of estrogen（E2）,luteinizing hormone（LH）,and progesterone（P）compared with the control group.In a rat model of PCO achieved via letrozole,it was found that the levels of TOS,MDA,oxidative stress index（OSI）and intracellular ROS were significantly increased,while the TAS level,SOD content were significantly decreased in the ovary homogenates（P〈0.05）.The results indicated that the PCOS pathological process significantly increased the oxidative stress production.ConclusionPCO rat model successfully induced via letrozole,and it is a suitable model for study of ovarian lesions.Oxidative stress also contributes to the PCO rat model,the protective effect of antioxidant might provide a new insight into the potential therapeutic solution to PCOS.