IOP-lowering effects for the application of human umbilical vein in non-penetrating deep sclerostomy in rabbits.

Aim: To estimate the effects of human umbilical vein (HUV) implanted under the sclera of glaucoma model on intraocular pressure (IOP) lowering and to investigate its related mechanisms

Methods: A total of 20 human umbilical veins (HUV) were collected from healthy fetus umbilical core. After the establishment of glaucoma model in rabbits, human freeze-dried umbilical vein was implanted under the sclera during NPDS, while for control group, sclerostomy was performed without implant. The formation of the filtration bleb and IOP were detected every 24 hours before surgery and on day 3, 7, 10 and 14 after surgery. Handheld pen-type Tono-pen II tonometer was used to measure IOP after topical anesthesia treatment. Each measurement has three duplicates. The incision recovery, filtration, conjunctiva congestion and anterior chamber inflammation were observed everyday after surgery.

Results: IOP was decreased dramatically with less inflammation than traditional sclerostomies with the application of HUV. The significant differences of IOP between the NPDS with and without HUV implant groups were shown up from 10 days after surgery. The average IOP in NPDS without HUV implant was 14.25mmHg, while for NPDS with HUV implant group, it was 12.30mmHg. This structure of filtration bleb, which allowed the aqueous humor to leave the eye, was formed for any type of surgery. However, 1-2 weeks later, filtration bleb was still existed in the group of sclerostomy with HUV implant and more stable than that of the surgery without HUV implant. Histological observations were performed on day 3, 7 and 14 after surgery. For the eyes under sclerostomy with HUV implant, HUV lumina was shown up on 3 days after surgery with few fibroblast cells near the sclera. On 7 days after surgery, HUV lumina was stably maintained but with obvious fibroblast cells and inflammatory cell. On 14 days after surgery, HUV lumina was still clearly observed but with scarring formation, which suggests that the IOP lowering effects might result from an effective drainage structure formation.

Conclusion: HUV might be an alternative material to make the drainage pathway for non-penetrating deep sclerostomy.