| Background Traumatic optic neuropathy (TON) is a common disease with severe visual function damage and poor prognosis. It has been argued over time that whether the utilization of glucocorticoid therapy on those patients who just suffered from TON is proper or improper. The surgical procedure of decompression of optic canal has been also controversial due to the lack of clinical evidence. Currently, the animal models are varied and ununified. Different laboratories use disparate modeling methods. During the clinical practice of traditional Chinese medicine of ophthalmology, the TON is classified as "hit blindness", and the Chongming-Yisun Decoction has been supposed to be effective in TON. The primary basic research demonstrated that retinal ganglion cell apoptosis is the main morphological change pathologically. Some of the key proteins such as Trk family receptor protein, p75NTR protein play credential roles during the apoptosis. Thus, in this study, we modeled the animals by horizontal traction methods with quantitative forces, and observed the loss of retinal ganglion cell by staining with fluorogold before we began this study. To detect the molecular changes of retinal ganglion cells, the levels of p75NTR mRNA, JNK protein, p75NTR protein and TrkB protein were detected from the normal group, control group and experimental group.Object To detect the levels of p75NTR mRNA and protein in the retina after nerve injury in rats, the changes of TrkB protein, the influence of the change of JNK protein as well as the application of Astragalus injection on the expression of p75NTR and TrkB protein in horizontal quantitative traction caused TON.Methods 1) Semi-quantitat ion of JNK protein with ELISA:60 rats were randomly selected in 2 groups, with 30 rats in each group:Group A:the transverse quantitative tension pull of the left optic nerve of 0.1 Nx 15 s, from the second day after operation 0.5 mL normal saline by intraperitoneal injection for 15 days; Group B:left eye was exposed as a sham operation. Nerve and around optic nerve but do not stretch injury. The right eye is disposed in each group. On the fifteenth day the left eye retinas were extracted frozen in liquid nitrogen, then the ELISA semi-quantitat ion experiments of JNK protein were practiced.2) Semi-quantification of p75NTR mRNA with RealTime-PCR test:24 rats were randomly selected into 2 groups, with 12 rats in each group: A group:the transverse tension quantitative pull the left optic nerve of 0.1 N×15 s, from the second day after operation with normal saline by intraperitoneal injection of 0.5 mL; group B:left eye was exposed to sham operation, optic nerve and circle but do not live in the optic nerve stretch injury. The right eyes were not treated. On the fifteenth day, the left eye retinal was frozen in liquid nitrogen, the detection of RT-PRC p75NTR.3) Randomly selected 90 rats were divided into 3 groups, within 30 rats in each group:A group:The transverse tension quantitative force pulled the left optic nerve with 0.1 N×15s, from the second day after operation with Normal Saline by intraperitoneal injection of 0.5 mL; GroupB:left eye was exposed to sham operation, optic nerve and optic nerve were without stretch injury; Group C:transverse tension quantitative force pulled the left optic nerve of 0.IN×15s, from the second day after operation treated with Astragalus Injection by intraperitoneal injection of 0.5 mL. The right eye was not treated as groups of normal control eyes.15 days later the bilateral retinal frozen in liquid nitrogen, were used to detect p75NTR and TrkB protein by Western Blotting.Results Compared with the controlled group, experimental group of retinal p75NTR mRNA and JNK protein and the protein expression of TrkB in 15d after operation were increased (P<0.05), unknown effects on expression of p75NTR in the retina (P>0.05); Astragalus injection can improve the damaged slightly expression of TrkB protein in the retinal optic the eye (P<0.05), and it was failed to determine the effects on expression of p75NTR in the retina.Conclusion The apoptosis of retinal ganglion cell by lateral traction was familiar with the reported mechanisms, which can be used to simulate traumatic optic neuropathy for molecular biology experiments; Astragalus injection may have a neuroprotective effect on retinal ganglion cells, which remained to be further researched.
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