磷酸三邻甲苯酯对母鸡神经组织线粒体超微结构及功能的影响

Effects of Tri-ortho-cresyl Phosphate (TOCP) on Mitochondrial Ultrastructure and Function in Hen’s Nerve Tissues

目的观察磷酸三邻甲苯酯(tri-ortho-cresyl phosphate,TOCP)对母鸡神经组织线粒体超微结构及功能的影响,探讨有机磷化合物诱导的迟发性神经毒性(organophosphorus easter-induced delayed neurotoxicity,OPIDN)的机制。方法成年罗曼母鸡16只,随机分为750mg/kg TOCP染毒组(n=12)和对照组(n=4)。TOCP按0.65ml/kg灌胃量一次性染毒,对照组给予等体积玉米油。分别于染毒后第1、5、15、21天观察线粒体结构的改变。另取成年罗曼母鸡96只,随机分为低、中、高剂量染毒组和1个对照组(n=24)。染毒组分别按185、375、750mg/kg经灌胃一次性染毒TOCP,对照组给予等体积玉米油。分别于染毒后第1、5、15、21天采用MTT比色法检测大脑、脊髓和周围神经(坐骨神经和胫神经)中琥珀酸脱氢酶活力的改变来间接代表线粒体呼吸链酶活力的改变。结果 TOCP组母鸡中枢神经系统大脑和脊髓中线粒体结构从染毒第5天开始出现病理改变,并随着OPIDN症状的发展逐渐加重;胫神经在第1天即可观察到线粒体及髓鞘的病理改变,且逐渐加重。染毒组与对照组相比,大脑中线粒体呼吸链酶活力的改变不明显,高剂量组在第15天和第21天出现明显降低,差异有统计学意义(P<0.05);脊髓与周围神经中线粒体呼吸链酶活力的变化趋势大致相同,中、高剂量组均从第5天开始明显下降,差异有统计学意义(P<0.05),低剂量组的最低峰值较中、高剂量组出现稍晚。各剂量组间及各时间点之间没有显著差异。结论 TOCP能使母鸡神经组织线粒体结构发生改变,并影响线粒体呼吸链关键酶的活力。

Objective To study the effects of tri-ortho-cresyl phosphate （TOCP） On mitochondrial ultrastructure and function in hen＇s nerve tissues and investigate the mechanism of the organophosphorus ester-induced delayed neurotoxity （OPIDN）. Methods Sixteen adult Roman hens were divided into two groups randomly： TOCP group （n=12） and control group （n=4）. Hens in TOCP group were treated with TOCP by gavage at dosage of 750 mg/kg bw and hens in control group received an equivalent volume of corn oil. At the 1st, 5th, 15th and 21 st day after exposure, hens were perfused with 0.9% saline and 0.1 mol/L PBS that contain 4% paraformaldehyde, and nerve tissues were dissected under electron microscopy. Another 96 adult Roman hens were randomly divided into four groups： three treated groups and one control group （n=24 each group）. The hens in three treated groups were given TOCP orally at dosages of 185, 375 and 750 mg/kg-bw respectively and control hens were treated with equivalent volume of corn oil. At 1st , 5th , 15th and 21st day after treatment, hens were sacrificed and the cerebrum, spinal cord and peripheral nerve （sciatic nerve and tibial nerve） were dissected. The mitoehondria in these nerve tissues were extracted to determine the changes of MTT reduction. Results Abnormal changes of mitochondria uhrastructure in hens＇ central nerve tissues （cerebrum and spinal cord） were found from the 5th day after exposure and aggravated as time went on. However, alterations in peripheral nerve tissue （tibial nerve） were observed at the 1st day after exposure. Compared with the control, MTT activity in cerebrum in high-dosage group was significantly decreased at the 15th day and 21st day after exposure （P〈0.05）. The changes of MTT activity in spinal cord and peripheral nerve shared the same trend. From the 5th day and 15th day after exposure, the MTT reduction of the medium-and high-dosage groups decreased significantly （P〈0.05）. The lowest value of MTT reduction in low-dosage group revealed a little later than the medium- and high-dosage groups. Besides, there was no significant difference of MTT reduction in the three treated groups as time went on. Conclusion TOCP can cause alterations of mitochondrial uhrastructure in hens＇ nerve tissues and disturb the activity of the enzymes in mitochondrial respiratory chain, which may be one of the mechanisms of OPIDN development.