title: Safety evaluation of intracameral and subconjunctival injection of a novel mucoadhesive polysaccharide isolated from Bletilla striata in rabbit eye.
abstract: OBJECTIVE
  To evaluate the safety of intracameral and subconjunctival injection of a novel mucoadhesive polysaccharide isolated from Bletilla striata in rabbit eye.
  
  
  METHODS
  One hundred microliters (100 μL) of Bletilla striata polysaccharide (BsP) at concentrations of 10, 40, and 80 mg/mL was intracamerally or subconjunctivally injected into rabbit eyes. Phosphate-buffered saline and 10 mg/mL hyaluronic acid solution were also injected as controls. BsP safety was evaluated via clinical follow-up and histological analysis. The dead corneal endothelial cells were observed by vital staining with alizarin red and trypan blue at 14 days after intracameral injection. Finally, in the intracameral injection study, scanning electron microscopy was performed for evaluation of the structure of the corneal endothelium and anterior lens capsules.
  
  
  RESULTS
  Subconjunctival injection of 10 mg/mL BsP does not cause pathological changes or an inflammatory response. Concentration greater than 10 mg/mL of BsP (40 or 80 mg/mL) leaded to a slight inflammatory response, but the rabbits recovered well in 3 days. The pathological observation further confirmed the safety of subconjunctival injection of BsP, and subconjunctival injection of 80 mg/mL BsP caused no lesion of the ocular tissues. Intracameral injection of 80 mg/mL of BsP did not cause a significant inflammatory reaction, and an even lower inflammatory response was observed in rabbits intracamerally injected with 40 or 10 mg/mL BsP. All rabbits intracamerally injected with BsP recovered within 7-14 days. BsP had little effect on the blood-aqueous barrier's integrity when the concentration was 10 mg/mL; at 40 or 80 mg/mL, a mild effect was observed, and the rabbits recovered in 1-3 days. Intracameral BsP injected at a concentration of 80 mg/mL had a negative impact on the corneal endothelium and lens, but concentrations of 40 or 10 mg/mL could be injected safely.
  
  
  CONCLUSIONS
  BsP injection into the subconjunctival space and anterior chamber in rabbits at low concentrations (such as 10 mg/mL) did not have adverse effects.
authors.affiliation: State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, No. 5 Yanerdao Road, Shinan District, Qingdao, People’s Republic of China. wuxianggen@126.com
authors.forename: Xianggen
authors.initials: X
authors.lastname: Wu
authors.forename: Xia
authors.initials: X
authors.lastname: Yang
authors.forename: Haoran
authors.initials: H
authors.lastname: Jiang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Xu
authors.forename: Ting
authors.initials: T
authors.lastname: Liu
authors.forename: Xinjie
authors.initials: X
authors.lastname: Zang
authors.forename: Huaqing
authors.initials: H
authors.lastname: Gong
mesh_terms: D000818:Animals; D000867:Anterior Chamber / Q000473:pathology; D003228:Conjunctiva; D003315:Cornea / Q000187:drug effects / Q000473:pathology; D004339:Drug Compounding; D004487:Edema / Q000139:chemically induced; D005123:Eye / Q000098:blood supply / Q000187:drug effects* / Q000473:pathology; D005260:Female; D006940:Hyperemia / Q000139:chemically induced; D007267:Injections; D056965:Injections, Intraocular; D007429:Intraocular Pressure / Q000187:drug effects; D007908:Lens, Crystalline / Q000473:pathology; D008297:Male; D009883:Ophthalmic Solutions; D029595:Orchidaceae / Q000737:chemistry*; D011134:Polysaccharides / Q000008:administration & dosage / Q000009:adverse effects*; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D013666:Tears / Q000187:drug effects / Q000378:metabolism; D014014:Tissue Adhesives / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D009883:Ophthalmic Solutions; D011134:Polysaccharides; D014014:Tissue Adhesives