Study On Covalent Cross-linking Erythrocyte Spectrin As The Surrogate Biomarker Of Neurotoxicity Induced By N-hexane

Objective: To study the relationship between covalent cross-linkingerythrocyte spectrin and n-hexane neurotoxicity. Method: SD rats were givenn-hexane of 0,168,675,2700 mg/kg for 8 weeks 5d/w)ig. General condition, (body weight,biochemical indexes (AST, ALT, TP, ALB, T-BIL, D-BIL, ALP,GGT, BUN, CRE, UA, GLB, GLU, LDH, CK, CK-MB, HBDH, TBA, CHE)and the main organic indexes (heart, liver, kidney, brain, spleen, lung andspermary) were observed or tested. Mixed nerves conduction velocity(MNCV)and muscle tension tested by slide board were carried out. Themuscle branch of the posterior tibial nerve was observed under lightmicroscope and electron microscope. Protein was eluted from erythrocytesand then the concentration was tested. It was isolated by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE), dyed by silverstaining , quantified by scanner and identified by Western blot. Results: In thegroup of 2700mg/kg, at the end of the test ( 8 weeks after the test started),animals had intoxication symptoms such as hindlimb paralysis, decreasing ofbody weight, muscle tension and MNCV. Biochemical indexes did notchanged significantly. Organic indexes(kidney, heart, liver, lung, brain)increased significantly (P<0.05). In the tibial nerve, morphological changessuch as axons decreased in numbers, degenerated were observed under lightmicroscope. In the axon, diversiform, swollen, demyelination and malalignedneruofilaments were showed under electron microscope. The concentrationerythrocytes protein of was 5.88±0.89g/L. A high-molecular-weight proteinband for about 410 kD was showed on SDS-PAGE. It was identified byWestern blot as the covalent cross-linking spectrin (a,?-heterodimer) with along "tailling". There was time-dose-effect relationship with the increase of　 ＩＩ 　covalent cross-linking spectrin. Conclusion: Animal model of neurotoxicityinduced by n-hexane could be successfully duplicated with hindlimb paralysis,neuropathy and erythrocyte spectrin covalent cross-linking. It was feasible forcovalent cross-linking erythrocyte spectrin to be the surrogate biomarker ofneurotoxicity induced by n-hexane. But it was necessary to further explore it.