Abstract
Abstract: :
Purpose:PKC γ has been previously shown to have an affect on gap junctions. Some gap junctions like Connexin 36 are involved in normal functioning of inner nuclear layer. The purpose of this study was to determine if the structure of retina was altered due to the PKC γ defficiency in the PKC γ knockout mouse with special emphasis on the Inner Nuclear layer (INL). Methods:We used control (b6129pf2/j100903 from Jackson Laboratory, Bar Harbor, MA) and PKC knock–out mice (B6;129p–Prkcctm1St1 from Jackson Laboratory, Bar Harbor, MA). Eyes were disected out of six week old animals then fixed in a fixative solution (2% paraformaldehyde 2.5% glutaldehyde and 0.1M cacodylate), then were post fixed with osmium tetraoxide, dehydrated and embedded in epon (LX112), thick sections were stained with toludine blue. Sectioning was done with the use of the Microtome. Sections were taken perpendicular to the optic nerve so all the layers could be observed. Both eyes were sectioned to the point until optic nerve was observed in all of the sections. Exact locations were confirmed by Low magnification photos which were taken with the use of a light Microscope. EM photos then were taken on the right side of retina of all the separate layers. Western blots were performed on freshly collected retina using monoclonal mouse PKC γ antibody from Sigma and rabbit anti Cx36 from Zymed. Results:Western blot of fresh retina showed that there was no PKC γ present in knockout and that normal Pkc γ levels were present in control mice. Cx36 levels were not altered. Measurements of all the thickness of all the layers (RPE, OS, ONL, OPL, INL, IPL) were taken 250 µm, 550µm, and 800µm from the optic nerve on the right side of the retina. Average thickness for control (RPE, OS, ONL, OPL, INL, IPL) were 5.49±1.01; 39.82±1.54; 43.46±1.29; 8.66±.94; 35.74±1.97; 50.49±3.77; for knock out (same order) 5.7367±.19; 48.24±1.25; 52.5±1.97; 8.9±1.83; 56.41±3.02; 77.66±9.66, respectively. Nuclei were counted at 100X magnification in the INL. The average number of nuclei per 1000µm2 were; control=34.13±1.97; knockout=15.85±1.12. INL in knockout mice had vacuoles which occupied 19.43%±1.36, of total area in the INL. There were no vacuoles present in the control. Conclusions:PKC γ deficiency has an affect on the structural organization of mouse retina. In the PKC γ knockout mice vacuoles were formed in the INL which resulted in reduction of total number of nuclei in that layer. PKC γ deficiency does not seem to affect thickness of the layers. Results imply a role for PKC γ in normal INL homeostasis.
Keywords: retina • anatomy • image processing