生长抑素对百草枯中毒小鼠肺损伤的保护作用及机制

The protective effect and mechanism of somatostatin on the lung injury of paraquat intoxicated mice

目的探讨生长抑素(SS)对百草枯(PQ)中毒小鼠肺损伤的保护作用及机制,为临床上治疗PQ中毒提供理论依据。方法将48只SPF级雄性BALB/c小鼠随机分为对照组、SS组、PQ组和PQ+SS组,每组12只。取SS组和PQ+SS组小鼠腹腔注射20ml/kgSS溶液,PQ组和对照组腹腔注射等量生理盐水;上述处理1h后,PQ组和PQ+SS组小鼠用60mg/kgPQ溶液一次性灌胃,对照组和SS组以等量生理盐水灌胃;上述处理3h后,SS组和PQ+SS组再次腹腔注射SS溶液(20ml/kg),PQ组和对照组腹腔注射等量生理盐水。观察各组小鼠一般状况的变化情况。处理24h后,各组随机抽取6只小鼠摘眼球取血,用酶联免疫吸附测定(ELISA)等方法检测小鼠血中肿瘤坏死因子α(TNF-α)、髓过氧化物酶(MPO)、白细胞介素-6(IL-6)水平,采血后取肺计算干湿重比(D/W)值;观察光学显微镜下各组小鼠肺组织病理学变化;取部分肺组织以化学比色法检测超氧化物歧化酶(SOD)、半胱氨酸天冬氨酸蛋白酶-3(Caspase-3)、丙二醛(MDA)水平,以蛋白免疫印迹(Westernblot)法检测核因子κB(NF-κB)蛋白量。结果对照组、SS组小鼠活动如常,一般状况良好;PQ组小鼠少食少动,对刺激反应迟缓,呼吸浅快伴呼吸音增粗,皮毛杂乱且无光泽,口唇及四肢皮肤均有不同程度青紫;PQ+SS组上述表现均较PQ组减轻。光学显微镜下可见,PQ组小鼠肺泡结构紊乱,破坏严重;PQ+SS组肺组织病理变化较PQ组有明显改善,病理学评分下降(P<0.05)。与对照组比较,PQ组小鼠IL-6、TNF-α、NF-κB、MPO、MDA及Caspase-3表达水平明显升高,肺组织D/W值及SOD活力明显下降(P<0.05);SS组各项指标水平变化差异均无统计学意义(P>0.05)。与PQ组比较,PQ+SS组IL-6、TNF-α、NF-κB、MPO、MDA及Caspase-3表达水平下降,肺组织D/W值及SOD活力升高(P<0.05)。结论PQ中毒可致小鼠肺损伤,SS可减轻PQ中毒小鼠的肺损伤,改善小鼠的一般生存状态,对PQ中毒所致的肺损伤起到一定的保护作用,可能是SS通过减轻PQ中毒所致肺损伤的炎症反应和氧化应激反应以及肺组织细胞凋亡来实现的。

Objective To explore the protective effect and mechanism of Somatostatin(SS) on the mice with Paraquat(PQ) poisoning, and to provide theoretical basis for clinical treatment of PQ poisoning. Methods 48 SPF male BALB/c mice were randomly divided into control group, SS group, PQ group and PQ+SS group, with 12 mice in each group. 20 ml/kg SS solution was intraperitoneally injected into the SS group and PQ+SS group, and the same amount of normal saline was intraperitoneally injected into the PQ group and control group. After 1 hour of the above treatment, PQ group and PQ+SS group were given 60 mg/kg PQ solution by one-time gavage, while the control group and SS group were given the same amount of normal saline by gavage. After the above treatment for 3 hours, the SS group and PQ+SS group were intraperitoneally injected with SS solution(20 ml/kg) again, and the PQ group and the control group were intraperitoneally injected with the same amount of normal saline. 6 eyeballs were randomly selected from each group for blood collection, and the levels of TNF-α, MPO and il-6 in the blood of mice were detected by ELISA and other methods. The left lung was taken after blood collection to calculate the D/W ratio. The levels of SOD, caspase-3 and MDA were detected in some lung tissues by chemical colorimetry, and the amount of NF-κB was detected by Western blot. The lung histopathological changes were observed under light microscope. Results The mice in the control group and SS group showed normal activity and good general condition;Mice in the PQ group ate less and moved less, responded slowly to stimulation, breathed shallow and fast with thickened breath sound, had messy and dull fur, and had varying degrees of cyanosis on their lips and limbs;The above performance of PQ+SS group was less than that of PQ group. Under the light microscope, the alveolar structure of PQ group was disordered and seriously damaged. The pathological changes of lung tissue in PQ+SS group were significantly improved compared with that in PQ group, and the pathological scores were decreased (all P<0.05). Compared with the control group, there was no significant change in the levels of various indicators in the SS group (all P>0.05). While the levels of inflammatory cytokines (IL-6,TNF-α, Protein expression of NF-κB), oxidative cytokines (MPO, MDA) and apoptotic cytokines caspase-3 in PQ mice were significantly increased, and the levels of oxidative cytokines SOD and lung tissue D/W were significantly decreased (all P<0.05). Compared with the PQ group, the PQ+SS group, the levels of inflammatory cytokines (IL-6,TNF-α, Protein expression of NF-κB), oxidative cytokines (MPO, MDA) and apoptotic cytokines caspase-3 decreased, and the levels of oxidative cytokines SOD and lung tissue D/W increased(all P<0.05). Conclusion PQ poisoning can cause lung injury in mice, while SS can alleviate lung injury in PQ poisoned mice, improve the general survival state of mice, and play a certain protective role in lung injury caused by PQ poisoning, which may be achieved by SS throμgh reducing the inflammatory response, oxidative stress response and lung tissue apoptosis in lung injury caused by PQ poisoning.