| ObjectiveDrug abuse is obvious social and medical problem at home and abroad. Heroin, morphine and pethidine are main poisons in our country at present. Long - term drug abuse will result in drug dependence, addiction and damage in nervous system.Long - term drug abuse with opiums poisons may cause degeneration and necrosis in nerve cells. There are encephalopathy in white matter in some cases. These pathological changes are in thalamencephalon, striatum, periaqueductal gray matter, cerebral cortex and pallidum, distribution of which are coincided with location of opiate receptors in central nervous system. It need further researching that whether neurocytes death in drug abuse is accompanied with apop-tosis and what s relation between neurons apoptosis and mechanism of drug dependence and addiction.NO is a free radical gas, which posses wide biological effects and has toxic effect to neurons. NO in blood serum of heroin drug abuser is high clearly. Neu-ronal constructive nitric oxide synthase(ncNOS) is a key enzyme in NO production, caspase -3, Fas and Bax protein are related to apoptosis. Increases of nc-NOS, caspase - 3, Fas and Bax content in neurons will cause apoptosis.There are many important matters which need more investigating and discussing.1. Damages of brain tissue by heroin, morphine and pethidine chronic dependence and spontaneous withdrawal, especially in neurons of cerebral cortex, periaqueductal gray matter and the ventral tegmental area which are closely related to opiums drug abuse;2. Whether do heroin, morphine and pethidine chronic dependence and spontaneous withdrawal cause neurons apoptosis in brain?3. Changes of ncNOS, caspase - 3 , Fas and Bax by immunohistochemistry and expresses of ncNOSmRNA and caspase -3mRNA by in situ hybridization in brain neurons by heroin, morphine and pethidine chronic dependence and spontaneous withdrawal;4. Impaired degrees in central nervous system by heroin, morphine and pethidine;5. Mechanisms of lesions in neurobiology and drug dependence by heroin, morphine and pethidine;6. Distinguishing feature and diagnostic value of immunohistochemical changes of ncNOS, caspase - 3, Fas and Bax in brain neurons by opiums drug abuse.Materials and MethodsBased on these bases and questions described above, in this study, the model of heroin, morphine and pethdine chronic dependence and spontaneous withdrawal in rats was built. 35 male Sprague - Dawley rats (200 - 250g at the start of experiments) were caged individually and allowed to habituate to the environment 2 days. The animals were randomly divided into control ( C) , heroin chronic dependence ( H1 ) , heroin spontaneous withdrawal ( H2 ) , morphine chronic dependence ( Ml ) , morphine spontaneous withdrawal ( M2 ) , pethdine chronic dependence(D1) , pethidine spontaneous withdrawal (D2) groups, each consisting of 5 animals. Seven groups were treated with saline, heroin, mor-phine or pethidine by subcutaneous injection (s. c. ) for 60 days. Dose of heroin was from 2mg kg-1 d-1 to 13mg kg-1 d-1. Morphine, from 20mg kg-1 d-1to 140mg kg-1 d-1 Pethdine, from 20mg kg-1 d-1to 140mg kg-1 d-1. Treatment interval was 6 h (7:30, 13:30, 19:30). Following 60 days of administration, when rats were completely chronic dependence to the opiums drugs, rats of C, H1, Ml and D1 groups were fixed by instillation with formaldehyde fixation solution and whole brains were removed. Natural opiate withdrawal was induced by ceasing opiums drugs administration in H2, M2 and D2 groups. Rats were observed for 4days. Then, the animals were killed according to method described above.The chosen other experimental methods were as follows:1. Conventional H. E. staining.2. Ultrastructural observation by transmission electron microscope.3. ncNOS, caspase-3, Fas and Bax immunohistochemistry by SP method.4. In situ hybridization of ncNOSmRNA and caspase - 3mRNA.5. Terminal deoxynucleotidyl transferase - mediated dUTP nick end labeling (TUNEL).6. Imag... |
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