An Experimental Study Of Batroxobin For The Treatment Of Blast Deafness In Guinea Pigs

Objective: To investigate the alterations of hearing function hemorhe- ology, cochlea microcirculation, morphology and enzyme cytochemistry following explosion exposure in guinea pigs. To investigate the preventive and therapeutic effect of batroxobin(DF-521) on blast deafiiess in guinea pigs. Methods: An animal model of blast deafness was established in guinea pigs. One hundred and twenty guinea pigs were divided into four groups: control group, DF-521 group, explosion-exposed + normal saline group and explosion-exposed+DF-521 group. Ten guinea pigs in explosion-exposed +normal saline group and another ten guinea pigs of explosion-exposed+ DF-521 group were chosen at random and their ABR threshold were measured lh before and 3h, 24h, 48h, 1w, 2w, 3w after being exposured to explosion respectively. At the 5 different time points which is 1 h before and 6h.. 24W.. 48W.. 2w after the exposure, 5 guinea pigs in each group were chosen to measure the hemorheological index, then they were decapitated and the cochlears were made into parafin sections, stria vascularis surface preparations, stria vascularis transmission electron microscope specimen, basilar membrance scanning electron microscope specimen and stria vessel endotheliocyte sucoino-dehydrogenase(SDI-I) enzyme cytochemistry elec- tron microscope specimen. The morphological indexes were observed with light microscope , transmission electron microscope and scanning electron microscope respectively, then image analysis was performed. Results: After explosion exposure, ABR threshold shift value of guinea pigs rose, then declined 48h after the exposure. The maximum value of about 95dB appearrd on the 24th hour, the permanent threshold shift value of about 35dB appeared on the 3rd week. All blood rheological parameters rose significantly, and almost recovered to normal on the 2nd week. Stria vessel permeability increased% Some erythrocytes were found in the endolymphatic space, blood stream interruption was found in the vessels. Stria vessels dilatated and collateral circulation opened, and then they recovered to normal on the 2nd week. The cytoplasma and mitochondria of the border cells, intermediate cells and stria vessel endotheliocytes in stria vascularis became swelling with vacuole in them. The crest of mitochondria ruptured. The mitochondria SDH activity of Stria vessel endotheliocytes declined. Hair cells were lost partially. The polarity of the stereocilia disappeared. The stereocilia fused and lost the regularity of arrangement. After being treated with DF-521, the ABR threshold shift value declined, the changes of blood rheological parameters declined, the erythrocyte could not be found in the endolymphatic space, stria vessel dilatation attenuated, border cells, intermediate cells and stria vessel endotheliocytes in stria vascularis and hair cells were less impaired, stria vessel endotheliocytic mitochondrias SDH activity slightly declined. Conclusions: The improved blast deafness animal model is good for studying the alterations of hearing function, hemorheology, cochlea microcirculation, morphology and enzyme cytochemistry following explosion exposure in guinea pigs. There are obvious abnormities in hearing fun ion, hemorheology, cochlea microcirculation, morphology and enzyme cytochemistry following explosion exposure. The use of DF-521 attenuates the abnormity, suggesting that DF-S2lcan be used to treat the blast deafness.