[Survival and phenotypic characterisctic of axotomized dorsal root ganglion neurons]

Using indirect inmunohistochemical method, the expression of Bcl-XL and Bax, anti- and proapoptotic proteins of Bcl-2 family, as well as of cytokine IL-1beta were studied to demonstrate the role of these substances in apoptosis regulation of sensory neurons of different subpopulations after the severance of their peripheral processes. For comparison of the capacity of these neurons to survive after central and peripheral axotomy, the expression of high-molecular component of neurofilament triplet NF200 and isolectin B4 (IB4) binding were studied. At day 30 after central axotomy, the total number of neurons in LIV-LV ganglia of rat was not changed, but the number of NF200+ neurons was decreased. In mouse Lv dorsal root, proapoptotic BaX protein was demonstrated in the nuclei of 46% of small neurons that accounts for 20% of the total neuronal number in this ganglion. By day 30 after the nerve crush separate Bax expression was found in the nuclei of 30% and in the cytoplasm of 20% of neurons. In intact animals, dorsal root ganglion antiapoptotic Bcl-XL protein was expressed in the cytoplasm of 30% of small neurons, as well as in satellite cells surrounding large and intermediate neurons. At day 30 after the nerve crush Bcl-XL expression in LV ganglion was not detected. IL-1beta was present in the cytoplasm of 17% of neurons belonging predominantly to the subpopulations of large and intermediate neurons. By day 30 after the nerve crush IL-1(+-neurons were not found.