Qualitative and quantitative studies in electron microscopy on influence of experimental ischemia of the vertebral arteries on the outer hair cells function in guinea pigs.

Histological studies were performed in 20 guinea pigs, both sexes, weighing 250-300 g and divided into two groups: I--control (anaesthetized animals without surgery), II--examined (in anaesthetized animals through an incision of the skin and muscles of the neck), the left or right vertebral artery was exposed and a vascular clip was inserted into the foramen of the transverse process of the 2-nd cervical vertebra. 50 days after this procedure, the guinea pigs were again anaesthetized by intraperitoneal injection of 35% solution of chloral hydrate, then vascular and cochlear perfusion with 3.6% solution of glutaraldehyde was performed. Simultaneously, by means of micropreparation, samples of cochlea were made for electron studies by means of electron microscope (Philips EM 300). In qualitative histopathologic examinations in guinea pigs of II group, the ischemia changes of the outer hair cells were greater in the side of irritation of the vertebral artery than at the opposite side. At the receptor side of these cells, under the membrane, there are multilamellar outgrowths in the shape of cisterns, partly expanded. The relative volume of external compartment of mitochondria in control group is as follows respectively: 0.15 +/- 0.0% at the right side and 0.15 +/- 0.08% at the left side, and in II group, respectively: 0.22 +/- 0.06% at the side of irritation and 0.19 +/- 0.07% at the opposite side. The obtained data in electron microscopy, both qualitative and quantitative pointed at ischemia changes of outer hair cells in guinea pigs after prolonged irritation of periarterial plexus of vertebral artery.