| Objective To investigate the expression of Nuclea factor-κB(NF-κB) on the retina of chronic ocular hypertension and the relationship between NF-κB and cellular apoptosis in rabbits. Method 51 healthy adult New Zealand rabbits were devided randomly into 5 groups: normal group, CH group, CH control group, CH+PDTC group and CH+PBS group. Except for normal group, the last 4 group were sub-divided into 4 timepoints: 1 week, 2 week, 4week and 6 week. There were 3 rabbits in each timepoint. Anterior chamber injections of 2% methylcellulose were performed respectively on rabbits to induce glaucoma in CH group, CH+PDTC group and CH+PBS group. Balanced salt solution was injected similarly to the rabbits of CH+PBS group for control. Synchronously, introvitreal PDTC or PBS injections were performed respectively on rabbits in CH+PDTC group and CH+PBS group weekly. The eyes were enucleated, fixed, embedded and sectioned. The morphological change of retina was studied by light microscopy. Retina was stained immunohistochemically using a polyclonal antibody NF-κB p65 and was evaluated with TUNEL method for the cellular apoptosis. Result 1. The animals had no severe syndrome after operation. The IOP in every group before experiment had no difference (P>0.05).And the IOP in CH group,CH+PDTC group and CH+PBS group increased obviously(P<0.01)after operation and kept in high standard. 2. The retinal injury of CH group was gradually aggravated by the ocular hypertension under light microscope. And the retina of CH control group was similar with normal group, without obvious injury. Contrarily, the retinal injury of CH+PDTC group seemed much more serious than that of CH group. But the retinal injury of CH+PBS was similar with that of CH group. 3. There was a little NF-κB expression in normal retina. NF-κB expression was gradually enhanced in CH group. In 1 week, NF-κB positive cells could be only found in GCL , the value of area density(VAD) of which is higher than that of normal group(p<0.05). In 2 week, the VAD of NF-κB expression increased sequentially (p<0.05). NF-κB positive cells could be found in GCL and INL. Until 4 week, NF-κB expressed significantly in GCL, INL and part of ONL, the VAD of which was much higher than that of 2 week(p<0.01). And in 6 week, NF-κB expressed in whole retina intensively, which was significantly enhanced (p<0.01). In CH+PDTC group, NF-κB expression was weaker than that of CH group(p<0.05) in 1 week and much weaker (p<0.01) in 2-6 week. 4. There was nearly no cellular apoptosis in normal retina. And TUNEL method showed a increase of cellular apoptosis in CH group. In 1 week, apoptosis cells could be only found in GCL , the apoptosis index(AI) of which is higher than that of normal group(p<0.05). In 2 week, AI increased sequentially (p<0.05). Apoptosis cells could be found in GCL and INL. Until 4 week, apoptosis appeared significantly in GCL, INL and part of ONL, AI of which was higher than that of 2 week(p<0.05). And in 6 week, apoptosis cells could be found in whole retina obviously, whose AI was enhanced (p<0.05). In CH+PDTC group, apoptosis cells were more than that of CH group(p<0.05) in 1-4 week, and much more (p<0.01) in 6 week. Conclusion: 1. Anterior chamber injections of 2% methylcellulose could induce chronic intraocular hypertension successfully. 2. The retina injury induced by chronic ocular hypertension spreaded from inner retina to the outer and was aggravated by the time of chronic ocular hypertension. 3. NF-κB could be activated on retina, the expression of which was gradually enhanced by the time of chronic ocular hypertension. 4. Cellular apoptosis could be induced by chronic hypertension on the retina and increased gradually by the time of chronic ocular hypertension. 5. NF-κB expression appeared much weaker on the retina of chronic ocular hypertension but apoptosis cells became much more after introvitreal PDTC injections. NF-κB may plays an important role in the anti-apoptosis mechanism.
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