Objective:To observe the effects of testosterone on optic nerve an d retinal ganglion cells (RGC) in experimental autoimmune encephalomyelitis (EAE ). Methods:Fourty one female Wistar rats were randomly divide d into 3 groups: the normal group (10 rats), the untreated control group (15 rats) and the testos terone group (16 rats). The rats in the first two groups were fed with 1% ethano l every day, and the rats in the testosterone group were fed with methyltestoste rone (0.25 mg/kg) every day. On the 20th day, EAE model was induced in the untre ated control group and the testosterone group by injecting guinea pig spinal cor d homogenate in complete Freund's adjuvant and bordetella pertussis vaccine. RGC were labeled with flurogold (FG) by injecting it in superior colliculus and lat eral geniculate body 7 days before establishing EAE model. All rats were fed wit h drugs continuously, and after 1430 days, rats in normal group and rats in un t reated control and testosterone groups who had symptoms within 48～72 hours were observed by light microscopy and flash visual evoked potential (FVEP) to detect the functional and morphological changes of optic nerve. The number of RGC was counted by fluorescence microscopy，and apoptosis of RGC was observed by termina l deoxynucleotidyl transferasemediated biotinylated UTP nick end labeling (TUN E L) Results:EAE rats presented weakness or paralysis of tail a nd hind limbs 10 days after establishing EAE model. Compared with the rats in the untreated contr ol group, the rats in the testosterone group had longer disease delitescence and lower clinical score (P=0.042). Extensive demyelination of optic nerves wi th the circuitous configuration was found in the untreated control group; while mild demyelination of optic nerves with regular figure was found in the testosterone group. In the testosterone group, the latency of N1、P and N2 wave was shorter w hile the amplitude ofN1-P and P-N2was higher than that in the untreated cont rol group (Plt;0.05). The number of RGC was (2284plusmn;132), (934plusmn;78, and (1725 plusmn;95)cells/mm2 in the normal, untreated control and testosterone groups, respectively; w hich was higher in testosterone group than that in untreated control group (P=0.028). The number of TUNEL positive cells was (4.02plusmn;0.16), (24.44plusmn;2.22), and (9.84plusmn;2.36) cells per high power field (times;400) in the 3 grou ps, respectively; wh ich was less in testosterone group than that in untreated control group (P＝0.025). Conclusions:Testosterone may reduce the incidence and clinical score of EAE, inhibit the apoptosis of RGC, alleviate the demyelinatio n of optic nerves, and improved the conduction function of optic nerves.
ObjectiveTo explore the histopathological changes of the pigs′ eyes in vivo after radial optic neurotomy (RON), and provide the experimental foundation for the safety of RON.MethodsA total of 12 healthy miniature pigs were used in the experiment, in whom 8 were executed at the 1st, 3rd , 7th , and 48th day respectively after underwent RON in both eyes, and 4 were executed at the 120th day after underwent RON unilaterally (the other eye was as the control in 2 and underwent single vitrectomy in 2). All the enucleated eyes were cut in sections routinely and embeded in paraffin. The sections were stained by HE, Masson trichrome staining or Luxol fast blue staining and the different sections of optic nerve were observed by light microscope.ResultsNo damages of the major vessel wall were found and the cerebral pia mater of orbital optic nerves kept integrated. At the 1st day after the operation, the incisions came into being and local hemorrhages infiltrated into the circumambience and backside. The vacuole-like change induced by the demyelination of optic nerve fiber located at the incisions. At the 3rdday, the vacuolelike changes widened. At the 7thday, the fibroblasts aggregated at the incision, with hyperplastic neuroglia cells and dispersed pigmented granules. Lymphocytes and monocytes were the major infiltrated inflammatory cells. At the 48th day, collagen filled in the incisions and aggregated neuroglia cells of the rear optic nerves behind the incision were found, which showed weak staining with obvious boundary which was somewhat beyond the midline of optic nerves. At the 120th day, localized atrophy of optic nerve occurred under the incision. No abnormal pathological findings were found in the normal eyes and the eyes underogo vitrectomy.ConclusionsLocalized atrophy of optic nerves comes into being after the normal pig eyes in vivo underwent RON. The surgery is safe to some extent.(Chin J Ocul Fundus Dis, 2005,21:13-15)