PM2.5长期动态低浓度恒定及高浓度间隔吸入暴露对雄性大鼠睾丸的损伤效应

Effects of long-term dynamic inhalation of PMwith constant low concentration and interval high concentration on testis damage in male rats

目的探讨长期低浓度恒定吸入与高浓度间歇吸入PM2.5对雄性大鼠生殖系统的影响。方法将24只6周龄SPF级Wistar雄性大鼠按体重随机分为对照(正常空气)组和4倍浓缩PM2.5恒定暴露组、8倍浓缩PM2.5间隔暴露组,每组8只。4倍浓缩PM2.5恒定暴露组每天连续暴露8 h;8倍浓缩PM2.5波动间隔组暴露1 h暂停1 h,每天共间隔暴露8 h,连续暴露3个月。对大鼠睾丸组织进行病理学检查,测定睾丸组织中氧化应激标志物超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)的活力和丙二醛(MDA)的含量以及促炎因子白细胞介素1β(IL-1β)、白细胞介素2(IL-2)、白细胞介素6(IL-6)、肿瘤坏死因子(TNF-α)的水平。结果与对照组相比,4倍浓缩PM2.5恒定暴露组睾丸组织曲精管间质水肿、增宽,有蛋白浆液渗出;8倍浓缩PM2.5间隔暴露组曲细精管间质明显增宽,部分曲细精管细胞层次减少,各级生精细胞排列紊乱甚至缺失。与对照组相比,4倍浓缩PM2.5恒定暴露组和8倍浓缩PM2.5间隔暴露组大鼠睾丸组织中SOD和GSH-Px的活力均降低,而MDA含量升高,差异均有统计学意义(P<0.05);且8倍浓缩PM2.5间隔暴露组大鼠睾丸组织中的MDA含量高于4倍浓缩PM2.5恒定暴露组,差异有统计学意义(P<0.05)。大鼠睾丸组织IL-1β、IL-2、IL-6、TNF-α水平的水平依次为8倍浓缩PM2.5间隔暴露组>4倍浓缩PM2.5恒定暴露组>对照组,差异均有统计学意义(P<0.05)。结论长期低浓度恒定吸入PM2.5与长期高浓度间隔吸入PM2.5均可使大鼠睾丸组织产生氧化应激反应和炎症反应,引发大鼠睾丸组织病理学损伤,最终影响大鼠的生殖功能,且高浓度间歇吸入PM2.5比低浓度恒定吸入PM2.5对睾丸组织的损伤更为严重。

Objective To explore the effects of long-time low concentration-constant inhalation and long-time high concentration-intermittent inhalation of PM2.5 on the reproductive system of male rats.Methods Twenty-four male 6-weekold SPF Wistar rats were randomly divided into three groups according to body weight,eight in each group,including control group inhaling normal air,four-fold concentration group constantly inhaling four-fold concentrated PM2.5 in air,and eight-fold concentration intermittent exposure group intermittently inhaling eight-fold concentrated PM2.5 in air.The 4-fold concentration group was continuously exposed to four-fold concentrated PM2.5 in air for eight hours a day;The 8-fold concentration intermittent exposure group was exposed to eight-fold concentrated PM2.5 in air for a total of eight hours a day with the intermittent exposure method(suspended exposure for 1 h after exposure for 1 h).The two groups were exposed for 3 months.The oxidative stress-related markers and proinflammatory factors in testicular tissue of rats were determined,included superoxide dismutase(SOD),glutathione peroxidase(GSH-Px),malondialdehyde(MDA),interleukin 1β(IL-1β),interleukin2(IL-2),interleukin 6(IL-6),tumor necrosis factor(TNF-α),and pathological examination was conducted.Results Compared with the control group,the seminiferous tubules were interstitial edema,interstitial enlarged and protein exudation in the 4-fold concentration group;In 8-fold concentration group,the seminiferous tubules were interstitial edema obviously,the cell layers of some seminiferous tubules decreased,and the arrangement of spermatogenic cells at all levels was disordered or even missing.Compared with the control group,the activity of SOD and GSH-PX in testicular tissues in the 4-fold concentration group and the 8-fold concentration group decreased,while the content of MDA increased,with significant differences(P<0.05).Moreover,the content of MDA in testicular tissue of rats in the 8-fold concentration group was higher than that in the 4-fold concentration group,with significant difference(P<0.05).The levels of IL-1β,IL-2,IL-6,and TNF-αin rat testis tissue were elevated in the order of 8-fold concentration group>4-fold concentration group>control group,the differences were statistically significant(P<0.05).Conclusion Both long-time low concentration-continuous inhalation and long-time high concentration-intermittent inhalation of PM2.5 can cause oxidative stress and inflammation in the testicular tissues of rats,which can lead to pathological damage of testicular tissues and affect the reproductive function of rats ultimately.Moreover,compared with low concentration-continuous inhalation of PM2.5,high concentration-intermittent inhalation of PM2.5 has more serious damage to testicular tissue.