Changes in platelet derived growth factor b chain expression following transection of the optic nerve

Purpose. To obtain information about changes in platelet-derived growth factor B chain (PDGF-B) in the optic system following transaction of the optic nerve Methods The unilateral optic nerves of 40 rats were transected with minimal damage. Both eyeballs and optic nerves were fixed, embedded in paraffin and sectioned on days 1-14 following transaction Immunostaining was performed using the streptavidin-biotin tmmunoperoxidase method. We used a mouse monoclonal antibody. PGF-007, as the primary antibody for PDGF B-chain immunostammg. For in situ hybridization, a digoxigenin-labeled cRNA probe for PDGF-B was used. Tissues subjected to a sham operation served as controls. Results In the control retina, ganglion cells, some bipolar and horizontal cells, as well as the retinal nerve fiber layer showed positive immunoreactivity for PIXJF-B. Expression of PIXiF-B mRNA was found in (he ganglion cells, some bipolar mid horizontal cells, but not in the retinal nerve fiber layer. In the transected side of the retina, PDGF-B immunoreactivity in the ganglion cells decreased from day 4 postoperation. Expression of mRNA in the ganglion cells decreased from day 3. The retinal ganglion cells showed atrophie changes from day . and decreased in number thereafter. In the distal stump of the transected optic nerve, swollen axons showed intense PIXiF-B immunoreactivity. Macrophages at the injury site rind some glial cells in the stump and distal portion ot the transected optic nerve revealed increased expression of PDGF-B protein and mRNA. Conclusions. The abobe suggests that PDGF-B was produced in the retinal ganglion cells and transported to the optic neive The decrease in PDGF-B m the retinal ganglion cells after transection seems to have caused the loss of ganglion cells, in other words. PDGFB in the retinal ganglion cells may play a role in the sunival of the cells. In addition, increased PDGF-B expression in the stump of the optic nerve may also play a necessary role in the cascade of tissue reactions in ihe optic nerve after Iransection.