Immunolocalization of TGF-β1, -β2 and -β3, and TGF-β receptors in human lens capsules with lens implants

Abstract 

Purpose: To establish the alteration in expression pattern of transforming growth factor (TGF)-βs and their receptors during repair of lens capsules after cataract surgery, we immunohistochemically located TGF-β isoforms and their receptors in human lens capsules before and after cataract surgery.  Methods: Ten post-cataract surgery capsular specimens were obtained during vitrectomy. Three sections of the anterior capsules were obtained during cataract surgery. A whole lens capsular bag immediately after lens extraction was obtained during vitrectomy. Cryosections of these specimens were processed for immunohistochemical analysis for TGF-β1, TGF-β2, TGF-β3, TGF-β receptor type I (TβR-I), type II (TβR-II) and type III (TβR-III), and were observed under light micros-copy. Results: Lens epithelial cells (LECs) lining the inner surface of the anterior capsules exhibited immunoreactivity for TGF-β2 and TβR-II. Immunoreactivity for TGF-β1, -β3, TβR-I and TβR-III was negative. In the whole capsular bag specimen, equatorial LECs were positive for TGF-β1 and -β2, but not for -β3. In post-cataract surgery specimens, antibodies for each TGF-β isoform labelled either the LECs or ECM accumulated on the capsules. Post-surgical LECs expressed TβR-I and TβR-II, and had also TβR-III in seven of the nine specimens examined.  Conclusion: Expression pattern of TGF-β s in quiescent LECs showed regional heterogeneity. Anterior LECs exhibited TGF-β2 immunoreactivity, while equatorial LECs were positive for TGF-β1 and -β2. Quiescent LECs expressed TβR-II. LECs proliferating around IOLs expressed proteins of each TGF-β isoform and each TβR. TGF-β s were also localized in the ECM on capsules undergoing repair. TGF-β3, TβR-I and TβR-III are up-regulated in LECs after cataract surgery.