Effects of minocycline on the apoptosis and the expression of Bcl-2 and Bax on facial motoneurons in a rat model of facial nerve ischemia

doi:10.3969/j.issn.1006-5725.2015.23.004

Abstract：Objective To study the expression levels of Bcl-2 and Bax on facial motoneurons and their action mechanism on apoptosis for investigating the protection of facial nerve ischemia by means of minocyline. Methods 120 adults male Sprague-Dawley rats were randomly divided into three groups , i.e. Sham-operated group (SH group, n = 40), petrosal artery interruption group (PAI group, n = 40) and minocyline treated group (MC group, n = 40). Facial nerve ischemia model was produced by occluding the tympanic segment of the petrosal artery. The rats in MC group were given intragastric injection of minocycline (60 mg/kg) one time per day, while an equivalent amount of 0.9% physiological saline was utilized at a same way in PAI and SH group. The histopathological changes of facial neurons were observed by HE staining 3 , 7, 14, 28 days after the ischemia. The changes of apoptosis in facial motoneurons were detected by TUNEL. The expression of Bcl-2 and Bax were measured by immunohistochemistry staining and Western blot. Results HE staining results showed that MC group had less severe nerve damage than PAI group. TUNEL results showed that the number of apoptotic cells in MC group was significantly less than that in PAI group (all P<0.05). The results of immunohistochemistry staining and Western blotting showed that the expression of Bcl-2 in MC group were significantly higher than that in PAI group , while the expression of Bax was lower (all P < 0.05 ). Conclusion Minocycline could inhibit the apoptosis and has a strong neuroprotective effect on facial motoneurons in a rat model of facial nerve ischemia.