A comparative study of oculomotor, trochlear and abducens nerves in Arabian foals

Abstract

We investigated the microscopic structure of transverse sections of the oculomotor, trochlear and abducens nerves of Arabian foals using stereological methods. Bilateral nerve pairs from 2-month-old female Arabian foals were analyzed. The tissues were embedded in plastic blocks, then 1 µm thick sections were cut and stained with osmium tetroxide and methylene blue-azure II. Stereology was performed using light microscopy. Morphometry showed that the right and left pairs of nerves were similar. The transverse sectional areas of the oculomotor, trochlear and abducens nerves were 1.93 ± 0.19 mm, 0.32 ± 0.06 mm and 0.70 ± 0.08 mm, respectively. The oculomotor nerve exhibited a significantly greater number of myelinated axons (16755 ± 1279) and trochlear (2656 ± 494) and the abducens nerves (4468 ± 447). The ratio of the axon diameter to myelinated nerve fiber diameter was 0.58, 0.55 and 0.55 for the oculomotor, trochlear and abducens nerves, respectively. Of the three nerves studied, the abducens nerve exhibited the greatest nerve fiber area, myelin area, nerve and axon diameters, and myelin thickness. The ratio of small myelinated nerve fibers was greatest in the oculomotor nerve.

Applying the area fraction fractionator (AFF) probe for total volume estimations of somatic, dendritic and axonal domains of the nigrostriatal dopaminergic system in a murine model

“…The probe is carried out using a fractionator tool over the area of interest, so as to apply a point-counting grid at each sampling site, and not the entire region under study. This method has allowed efficient and robust area and number estimations of two dimensional elements, such as axons in nerve or tracts [3, 9, 18, 19]. It is, on the other hand, intriguing that the AFF probe has been mostly utilized for area estimations [9] and not, for instance, combined with serial sectioning analysis for estimations of small objects’ volume, as with the Cavalieri method [2].…”