Neuroprotective Effect Of MnTBAP On Facial Neurons After Facial Nerve Injury In Rats

PrefaceExtracranial segment of facial nerve traveling long distances, close relationship with the parotid gland and other organs. With the ear surgery, cancer,and injury, including mechanical, physical and chemical nature of injury, iatrogenic injury, including traumatic injury of facial nerve segment is in a rising trend, the incidence is about 17-32%. After facial nerve injury not only causes of maxillofacial deformities, but also affect the mouth, eyes and other features, from the physical, psychological, and social adverse effects to patients. Therefore, the repair of facial nerve injury is related to an important research topic in the field. Although the current clinical use of fine microsurgical techniques to better restore nerve continuity, but the recovery of nerve function is still not satisfactory. After the face nerves damaged, the nerve body fluid microcirculation disorder, which led to a sharp increase in glucocorticoid hormone levels, oxidative stress, produced a large number of products, cytokines (Cytokine) a large number of released and intracellular ion changes in neurons through the inverse of axoplasm transport target tissue or in support of the organization arising from neurotrophic factor (NTF) interrupts and so on, the final mitochondrial damage, cytochrome C (Cyto-c) release. Cyto-c, where the participation of ATP-activated apoptosis-activating factor (Apaf-1), activation of Apaf-1 via its caspase recruitment domain (CARD) and caspase-9 precursor of the original domain of integration, leading to caspase-9 self-activation. Cyto-C, Apaf-1 and caspase-9 precursor form a "apoptotic bodies" (apotosome), activated caspase-9 and further induction of caspase such as caspase-3 activation caused apoptosis. This research is to observe the neuroprotective effect of MnTBAP following facial nerve crush in rats and its impact on the expression of TUNEL,Cyto-c and Caspase-9,Caspase-3.MethodLeft facial nerve was performed crush plus MnTBAP, right facial nerve acted as crush plus saline. Sham-operated group, only the total exposure to pairs of facial nerve injury of neural stem. Each time point after injury, general observation of the recovery of facial paralysis in rats; The morphology of facial neurons were observed under light microscope; The apoptotic cells of injured FMNs were detected by TUNEL staining; The expression of Cyto-c and Caspase-9,-3 were detected by immunohistochemistry method.ResultMnTBAP play an important role in the functional recovery following facial nerve crush; The survival rates of FMNs decreased gradually from the 3th d,the survival rates of FMNs at each time point in MnTBAP side were significantly higher than that in control side; TUNEL-positive cell was observed on the 7td d after injury both in MnTBAP side and control side, and it's number peaked on the 14th d. The apoptotic cell numbers in the MnTBAP side were significantly lower than that in control side at each time point; The expression of Cyto-c,Caspase-9 increased Id after injury and peaked at 7d, the expression level of Cyto-c,Caspase-9 in MnTBAP side was significantly lower than that in control side at each time point except the 28,42th d. The expression of Caspase-3 increased 3d after injury and peaked at 14d. The expression level of Caspase-3 in MnTBAP side was significantly lower than that in control side at each time point.ConclusionMnTBAP can effectively help functional recovery following facial nerve crush; inhibition of apoptosis and decreased expression of Cyto-c and Caspase-9,-3 by MnTBAP may be an important mechanism for treatment of traumatic facial paralysis.