Changes of mitochondrial ultrastructures and function in central nervous tissue of hens treated with tri-ortho-cresyl phosphate (TOCP).
Tri-ortho-cresyl phosphate (TOCP), an organophosphorus ester, is capable of producing organophosphorus ester-induced delayed neurotoxicity (OPIDN) in humans and sensitive animals. The mechanism of OPIDN has not been fully understood. The present study has been designed to evaluate the role of mitochondrial dysfunctions in the development of OPIDN. Adult hens were treated with 750 mg/kg·bw TOCP by gavage and control hens were given an equivalent volume of corn oil. On day 1, 5, 15, 21 post-dosing, respectively, hens were anesthetized by intraperitoneal injection of sodium pentobarbital and perfused with 4% paraformaldehyde. The cerebral cortex cinerea and the ventral horn of lumbar spinal cord were dissected for electron microscopy. Another batch of hens were randomly divided into three experimental groups and control group. Hens in experimental groups were, respectively, given 185, 375, 750 mg/kg·bw TOCP orally and control group received solvent. After 1, 5, 15, 21 days of administration, they were sacrificed and the cerebrum and spinal cord dissected for the determination of the mitochondrial permeability transition (MPT), membrane potential (Δψ(m)) and the activity of succinate dehydrogenase. Structural changes of mitochondria were observed in hens' nervous tissues, including vacuolation and fission, which increased with time post-dosing. MPT was increased in both the cerebrum and spinal cord, with the most noticeable increase in the spinal cord. Δψ(m) was decreased in both the cerebrum and spinal cord, although there was no significant difference in the three treated groups and control group. The activity of mitochondrial succinate dehydrogenase assayed by methyl thiazolyl tetrazolium (MTT) reduction also confirmed mitochondrial dysfunctions following development of OPIDN. The results suggested mitochondrial dysfunction might partly account for the development of OPIDN induced by TOCP.
Institute of Toxicology, Shandong University, Shandong, PR China.
Xing
X
Xin
Tao
T
Zeng
Dan-Dan
DD
Dou
Sheng
S
Zhao
Jing-Yun
JY
Du
Jing-Jing
JJ
Pei
Ke-Qin
KQ
Xie
Xiu-Lan
XL
Zhao
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002540:Cerebral Cortex / Q000187:drug effects* / Q000503:physiopathology / Q000648:ultrastructure; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000648:ultrastructure*; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D008933:Mitochondrial Swelling / Q000187:drug effects; D020258:Neurotoxicity Syndromes / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D010968:Plasticizers / Q000633:toxicity*; D013116:Spinal Cord / Q000187:drug effects* / Q000503:physiopathology / Q000648:ultrastructure; D013997:Time Factors; D014317:Tritolyl Phosphates / Q000633:toxicity*
D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D010968:Plasticizers; D014317:Tritolyl Phosphates; C025541:tri-o-cresyl phosphate