| The proliferation, differentiation and apoptosis of Lens epithelial cells (LECs) has close relations with after cataract. LECs is monolayer cube epithelium under anterior capsule, which is the most active part in lens metabolism. LECs plays an important role in the growth, differentiation and restoration of lens. To study the proliferation, differentiation and apoptosis of LECs is significant to illuminate the mechanism of posterior capsular opacification (PCO).PCO is the most common complication of cataract surgery, occurring in up to 50% of cases and a recent clinical survey suggested that the incidence is declining with the improvements in surgical technique. Cataract surgery induces a wound healing response in the lens with cellular proliferation and laying down of extracellular matrix. PCO results from the proliferation of LECs remaining in the capsular bag after any type of extracapsular cataract extraction. Visual loss occurs as a result of centripetal migration of LEC associated with fibrosis and wrinkling of the posterior capsule.The cell culture is the main method to study the proliferation and differentiation of LECs. At present, the most common model in our country is the cell culture in vitro.Whereas, our study utilized special space in vivo and established a new culture method. Through the incision of cornea, without the breakdown of the blood-aqueous barrier, the lens anterior capsule or capsular bag of one rabbit eye was cultured in the anterior chamber of the other rabbit eye. The purpose was to investigate the proliferation, differentiation and apoptosis of LECs in the aqueous humor relatively without breakdown of the blood-aqueous barrier, and to prove the effect of decreasing the breakdown of the blood-aqueous barrier on the PCO.1. MethodsForty rabbits were randomly divided into 3 groups, and surgery was performed as follows:(1) Anterior capsule group: anterior capsule of one eye was sent into the anterior chamber of the other eye of the same rabbit through the small incision of the cornea and was cultured;(2) Capsular bag group: capsular bag of one eye was culture in the same way as the anterior capsule group;(3) Cataract surgery group: extracapsular cataract extraction (ECCE) was performed on both of the eye of the rabbit.After different weeks, the samples were collected. The proliferation, differentiation and apoptosis of LECs of every group was investigated and compared. The normal LECs on the anterior and equator was collected and served as a control.2. ResultsThe results showed that the inflammation of anterior chamber in cataract surgery group was rather more obvious than that in anterior capsule group and capsular bag group. We found that LECs on anterior capsule couldn't survive when it was exposed to normal aqueous humor. With the culture time, apoptosis of cells gradually began to be induced and cells completely fell off from anterior capsule at week 7 after surgery. In the culture progress of capsular bag group, at week 1 after surgery, a few cells existed on posterior capsule where anterior and posterior capsule contacted. The cellshad abnormal modality and poorly grew which were remainder of survival cells on anterior capsule. The cells could barely be seen on posterior capsule and equator by week 5 after surgery. The fibrosis of LECs didn't appear at any time of culture process. The time when cells completely fell off from posterior capsule was shorter than that in anterior capsule group. However, in cataract surgery group, with the breakdown of blood-aqueous barrier, the cells greatly proliferated to form PCO. At week 1 after surgery, the fibrosis of LECs appeared and by week 3 cells on equator proliferated to form obvious Soemmering loop. A plenty of cells distributed evenly on the center of posterior capsule. The thickness of Soemmering loop increased and the transparency decreased. And the cells on posterior capsular and the fibrosis were more obvious.3. Conclusions(1) To study the proliferation, differentiation and apoptosis of LECs is significant to illuminate the mechanism of PCO. At present, the most commonly model in our country is the cell culture in vitro. But the culture in vitro is rather different with that in vivo. Our study utilized special space in vivo and established a new culture method— —culture in anterior chamber. The purpose was to investigate the proliferation, differentiation and apoptosis of LECs in the aqueous humor relatively without breakdown of the blood-aqueous barrier, and to prove the effects of decreasing the breakdown of the blood-aqueous barrier on the PCO.(2) The results showed that LECs when exposed with normal aqueous humor couldn't survive and the apoptosis of cells appeared. But the breakdown of the blood-aqueous barrier and the residual lens cortex could protect LECs and induce the proliferation and differentiation of cells through the factors such as extracellular matrix, cytokine and nutrient element. The results indicated that these substances were involved in the formation of PCO. |
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