[Morphological changes of corneal nerve in rats exposed to n-hexane.]

To investigate the injury in the corneal nerve and cornea of rats exposed to n-hexane.

Thirty-two SD male rats were randomly divided into one control group and four n-hexane groups. The four n-hexane groups inhaled 35.2 g/m(3) n-hexane statically for 1, 3, 7 and 14 d respectively, while the rats in the control group inhaled air. The corneal nerve damage was investigated with golden staining and transmission electron microscope. Histopathological and ultrastructure changes of cornea were analyzed also.

The concentration of n-hexane in blood of rats in different experimental groups was (242.91 +/- 59.68), (668.77 +/- 221.74), (1021.21 +/- 545.71) and (1140.42 +/- 468.44) microg/L, increased gradiently with time exposed to n-hexane. In the rats exposed to n-hexane for 7 and 14 d, there appeared fewer corneal nerve bundles and lower density of nerve fiber at the center of cornea, under electron microscope, the lamellar sheath of nerve fiber in the corneal epitheliums appeared intermittent, the neuroplasm of endings was partly lysed and became vacuolar, the microfilament and racuole of neuraxon decreased. In the group exposed to n-hexane for 14 d, the microvillus of cornea epithelium were decreased. In some basal cells there appeared pyknotic nucleus and vacuole, mitochondria were swollen or disappeared.

The structure of corneal nerve and cornea is damaged in the rats exposed to n-hexane, thus leading to dysfunction of cornea.