RESUMO
Recently diabetic neuropathy has been postulated to occur from reduced availability of neurotrophic factor. This experiment was performed to identify the effect of nerve growth factor on dorsal root ganglia (DRG) in the strepto-zotocin-induced diabetic rat using morphometry and immunohistochemistry. The results obtained are as follows : 1. Unlike in the diabetic group where the type A and B cells were significantly decreased in their total numbers and sizes, these cells were normal in NGF-administered diabetic group. 2. Numbers of cells immunoreactive with SP and CGRP were also significantly decreased in the diabetic group. However, the NGF-administered diabetic group did not show any reduction in the number of these cells. 3. Mean sizes of cells immunoreactive with SP and CGRP cells were reduced in the diabetic group by 18.1% and 26.6% respectively (P<0.01). On the other hand, in NGF-administered diabetic group, mean sizes of SP-immunoreactive cells were increased (10.5%) which was not statiatically significant, and those of CGRP-immunoreactive cells were decreased (18%) compared to the control group (P<0.01). 4. In the diabetic group, many of nerve cell bodies showed some degenerative characteristics including neuron-satellite cell interface of irregular shape, the presence of a number of vacuoles and dense bodies, and nucleus of irregular contour. However, NGF-administered diabetic group exhibited neuron-satellite cell interface of regular form, many neurofilaments and neurotubules, and normal intracellular organelles. These results suggest that administration of NGF protects spinal ganglion cells from morphometric and morphological changes which are associated with a streptozotocin -induced diabetic neuropathy.
