Study Of Effect Of Microenvironmental Changes On Apoptosis Of Fibers Of Lens And Degradation Of Cell Organ After Vitrectomy

Objective:to observe opacity degree of rabbit lens,expression of Caspase-8 and the change of the degradation in the fibers of lens during early period after vitrectomy with different filler.To study the effect of microenvironment after vitrectomy on the apoptosis of fibers of lens and the degradation of cell organ.Methods:60 Dutch Belted rabbits were randomly divided into 3 groups . The right eyes were underwent partial vitrectomies .Vitreous cavity, respectively, replaced by balance salt solution (BSS),20% perfluoropropane gas(C3F8) or silicone oil. The intraocular pressures were measured with tonometer,and the lens shape were observed with slit lamp microscope on the 3rd,7th,14th,20th day and 1th,2th,3rd month after operation.Two eyes were randomly selected in each group at 1th,3rd,7th day and 1th,3rd month after surgery. Morphologic changes of lens fiber cells were observed by pathological examination. Apoptosis of lens fiber cells was detected by TUNEL technique, and quantified by calculating the apoptotic index (AI) . The expression of Caspase-8 was determined by immunohistochemistry . Contralateral eyes were set as the control group. Results:the complicated cataract rate of gas group,silicone oil group,BBS group was 100%,40%,20%,there was no significant differentce of IOP among the three groups.In control group, the shape of the lens fibre nuclei under the lens epithelial cells was elongated . In the experimental group, some of the lens fibre nuclei at the same place had a more spherical form, which increase gradually later. On the first day after surgery, increased apoptosis on the lens fiber cells was detected, and reached a peak at the 3rd and 7th day. The reduction of apoptosis began at the first month. But the AI of each experimental group was significantly higher than that of the control group (P<0.05). The Caspase-8 was expressed clearly in the lens fiber cells of experimental groups ,but a weak expression was detected in the lens epithelial cells. Conclusions: different intraocular filling materials leading dysbolism of fibers of lens may be related with the complicated cataract of rabbits lens after vitrectomy. The change of micro-environment caused by vitrectomy and different fillers(C3F8, silicone oil or BSS) can induce increasing apoptosis and premature differentiation of lens fiber cells, whith was connected with each other.Caspase-8 increaseing after the vitrectomy cues Caspase-8 signaling pathway may play an important role in apoptosis of the lens fiber cells.All of these settled a rationale for the study of the pathogenesis of complicated cataract after vitrectomy.