BackgroundDry eye is a common disease worldwide, and animal models are critical for the study of it. At present, there is no research about the stability of the extant animal models, which may have negative implications for previous dry eye studies. In this study, we observed the stability of a rabbit dry eye model induced by the topical benzalkonium chloride (BAC) and determined the valid time of this model.Methods and FindingsEighty white rabbits were randomly divided into four groups. One eye from each rabbit was randomly chosen to receive topical 0.1% BAC twice daily for 2 weeks (Group BAC-W2), 3 weeks (Group BAC-W3), 4 weeks (Group BAC-W4), or 5 weeks (Group BAC-W5). Fluorescein staining, Schirmer's tests, and conjunctival impression cytology were performed before BAC treatment (normal) and on days 0, 7, 14 and 21 after BAC removal. The eyeballs were collected at these time points for immunofluorescence staining, hematoxylin and eosin (HE) staining, and electron microscopy. After removing BAC, the signs of dry eye in Group BAC-W2 lasted one week. Compared with normal, there were still significant differences in the results of Schirmer's tests and fluorescein staining in Groups BAC-W3 and BAC-W4 on day 7 (P<0.05) and in Group BAC-W5 on day 14 (P<0.05). Decreases in goblet cell density remained stable in the three experimental groups at all time points (P<0.001). Decreased levels of mucin-5 subtype AC (MUC5AC), along with histopathological and ultrastructural disorders of the cornea and conjunctiva could be observed in Group BAC-W4 and particularly in Group BAC-W5 until day 21.ConclusionsA stable rabbit dry eye model was induced by topical 0.1% BAC for 5 weeks, and after BAC removal, the signs of dry eye were sustained for 2 weeks (for the mixed type of dry eye) or for at least 3 weeks (for mucin-deficient dry eye).

The differences of tear inflammatory cytokines between patients with active and inactive TAO indicated that orbital inflammation may be involved in the ocular surface damage of TAO.

Purpose: This study was undertaken to investigate the effects of recombinant human epidermal growth factor (rhEGF) and basic fibroblast growth factor (bFGF) on corneal wound healing and neovascularization (CNV). Methods: The positive effects of 10 ng/ml rhEGF and bFGF on the proliferation of corneal epithelial cells (SD-HCEC1s), rabbit keratocyte cells (RKCs) and human umbilical vein endothelial cells (HUVECs) as well as the effects on the migration capacity on HUVECs were observed. An animal central corneal wound and CNV model was established in rabbits. One eye of each group was chosen randomly for topical administration of rhEGF, bFGF or normal saline, and variability in the area of corneal epithelial wound healing and CNV was observed. Results: The optimal concentration of rhEGF and bFGF for the proliferation of corneal epithelial cells was 10 ng/ml. The promotive effect of 10 ng/ml rhEGF on the proliferation of RKCs and HUVECs was less than that of 10 ng/ml bFGF. In the animal experiment, the healing rate of the corneal epithelium in the rhEGF group was better than in the other groups on day 1. On day 3, the healing rates of the 3 groups were nearly equal. The CNV area in the rhEGF group was less than that of the bFGF group. Conclusions: rhEGF and bFGF both had promotive effects on corneal epithelial wound healing, but rhEGF had a weaker promotive effect on CNV than bFGF. With long-term application of growth factor drugs, rhEGF is suggested for lessening the growth of CNV.

Purpose: To examine whether dry eye severity is a risk factor for pterygium activity and whether vascular endothelial growth factor (VEGF) is crucial in the cross talk between pterygium and dry eye. Methods: A total of 103 patients with primary pterygium (Pteg) were included in the study group; they were divided into 2 groups according to the complication of dry eye (DE) (Pteg + DE group, Pteg -DE group). Further, 60 patients with just dry eye (DE group) and 60 normal individuals (normal) were included as 2 control groups. DE severity and pterygium activity were measured, and unstimulated tear samples and pterygium tissues were collected for cytokine detection. Results: (1) Tear detection: VEGF expression increased in the Pteg + DE group compared to the Pteg -DE, DE, and normal control groups; VEGF was especially increased in the active Pteg + DE group. VEGF concentration was positively correlated with pterygium activity. (2) Tissue detection: the mRNA expression of VEGF was upregulated in the active pterygium group. Conclusions: Inflammation played an important role in the development of dry eye and pterygium. VEGF was the core molecule in the cross talk, which might explain the high incidence of the coexistence of these 2 diseases.

To construct an auto-tissue-engineered lamellar cornea (ATELC) for transplantation, based on acellular porcine corneal stroma and autologous corneal limbal explants, a dynamic culture process, which composed of a submersion culture, a perfusion culture and a dynamic air-liquid interface culture, was performed using appropriate parameters. The results showed that the ATELC-Dynamic possessed histological structure and DNA content that were similar to native lamellar cornea (NLC, p>0.05). Compared to NLC, the protein contents of zonula occludens-1, desmocollin-2 and integrin β4 in ATELC-Dynamic reached 93%, 89% and 73%, respectively. The basal cells of ATELC-Dynamic showed a better differentiation phenotype (K3−, P63+, ABCG2+) compared with that of ATELC in static air-lift culture (ATELC-Static, K3+, P63−, ABCG2−). Accordingly, the cell-cloning efficiency of ATELC-Dynamic (9.72±3.5%) was significantly higher than that of ATELC-Static (2.13±1.46%, p<0.05). The levels of trans-epithelial electrical resistance, light transmittance and areal modulus variation in ATELC-Dynamic all reached those of NLC (p>0.05). Rabbit lamellar keratoplasty showed that the barrier function of ATELC-Dynamic was intact, and there were no signs of epithelial shedding or neovascularization. Furthermore, the ATELC-Dynamic group had similar optical properties and wound healing processes compared with the NLC group. Thus, the sequential dynamic culture process that was designed according to corneal physiological characteristics could successfully reconstruct an auto-lamellar cornea with favorable morphological characteristics and satisfactory physiological function.

Background: Dry eye is a common disease worldwide, and animal models are critical for the study of it. At present, there is no research about the stability of the extant animal models, which may have negative implications for previous dry eye studies. In this study, we observed the stability of a rabbit dry eye model induced by the topical benzalkonium chloride (BAC) and determined the valid time of this model.Methods and Findings: Eighty white rabbits were randomly divided into four groups. One eye from each rabbit was randomly chosen to receive topical 0.1% BAC twice daily for 2 weeks (Group BAC-W2), 3 weeks (Group BAC-W3), 4 weeks (Group BAC-W4), or 5 weeks (Group BAC-W5). Fluorescein staining, Schirmer's tests, and conjunctival impression cytology were performed before BAC treatment (normal) and on days 0, 7, 14 and 21 after BAC removal. The eyeballs were collected at these time points for immunofluorescence staining, hematoxylin and eosin (HE) staining, and electron microscopy. After removing BAC, the signs of dry eye in Group BAC-W2 lasted one week. Compared with normal, there were still significant differences in the results of Schirmer's tests and fluorescein staining in Groups BAC-W3 and BAC-W4 on day 7 (P,0.05) and in Group BAC-W5 on day 14 (P,0.05). Decreases in goblet cell density remained stable in the three experimental groups at all time points (P,0.001). Decreased levels of mucin-5 subtype AC (MUC5AC), along with histopathological and ultrastructural disorders of the cornea and conjunctiva could be observed in Group BAC-W4 and particularly in Group BAC-W5 until day 21. Conclusions:A stable rabbit dry eye model was induced by topical 0.1% BAC for 5 weeks, and after BAC removal, the signs of dry eye were sustained for 2 weeks (for the mixed type of dry eye) or for at least 3 weeks (for mucin-deficient dry eye).