Aging-related alteration of trigeminal ganglion structures; A histologic study of Neuronal population, Satellite Ganglionic Cells and Vascular bed

Background: Aging is associated with signs that are similar to peripheral neuropathy and age-related decline in the peripheral sensory system and proprioceptive functions. Trigeminal ganglion (TG) is one of the sensory ganglion providing sensory information from the orofacial region. Ultrastruchral alteration in neuronal population of TG has been reported.Aim of work: Examine the effects of aging on neuronal population, distribution, and satellite ganglionic cells (SGCs) and compare with the TG of young animal. Materials and Methods: Old male Wistar rats (32 weeks old) (250±20g) and young male (4weeks old) (150±20g) were deeply anesthetized with chloroform. To avoid inadvertent mechanical dark neuron formation, each animal was transcardially perfused with 500ml of 4% paraformaldehyde in0.1 M phosphate-buffered saline. The skull cap was cut open and the TG was exposed and removed carefully. The sections were selected according to the systematic random sampling(SRS) and stained with H&E. From each section 10 fields(200×160µm) were selected randomly and the profile of neurons, neuronal shapes, SGCs, and the number of capillary profiles were studied. Results: The measured profile of neurons in the TG of young (17.11± 4.8) and old animals (15.69±4.4) showed a meaningful level of differences(p 0.05). The number of capillary profiles in the TG of young animals (7±2.73) showed a meaningful difference with those of old animals (3.8±0.83) (p < 0.05). Conclusion: With aging neuro-glial population and vascular bed of TG undergo a series of quantitative and qualitative alterations. Precisely aging is associated with decrease in neuronal size and vascular bed while the number of SGCs remains without significant changes. Aging leads to changes in neuronal distribution and likely morphologic alterations in SGCs subpopulation.