Protective Effects Oncorneal Endothelium During Intracameral Irrigation Using N-(2)-l-alanyl-l-Glutamine

Abstract

Corneal endothelial disease is a global sight-threatening disease, and corneal transplantation using donor corneas remains the sole therapeutic option. A previous work demonstrated that N (2)-alanyl-glutamine (Ala-Gln) protected against apoptosis and cellular stress, and maintained intestinal tissue integrity. In this pursuit, the present study aimed to examine the effect of Ala-Gln in the protection of the corneal endothelium and expand its range of potential clinical applications. Mice in the control group were intracamerally irrigated with Ringers lactate injection, whereas those in the experimental group were irrigated with Ringers lactate injection containing Ala-Gln. The mean intraocular pressure increased to 44 ± 3.5 mm Hg during intracameral irrigation (normal range 10.2 ± 0.4 mmHg). In vivo confocal microscopy results showed that the addition of Ala-Gln protected the morphology, structure, and density of the corneal endothelial cells. Optical Coherence Tomography (OCT) measurements showed that corneal thickness was not significantly different between the two groups, because of the immediate corneal edema after irrigation, but the addition of Ala-Gln obviously promoted the recovery of the corneal edema. Scanning electron microscopy indicated that the corneal endothelial cells were severely ruptured and exfoliated in the Ringer's group accompanied with cellular edema, when compared with the Ala-Gln group. The intracameral irrigation using Ala-Gln protected the structure and expression of cytoskeleton and Na-K-ATPase, which exhibited a regular distribution and significantly increased expression in comparison to Ringer's group. Furthermore, Ala-Gln maintained the mitochondrial morphology and increased the activity of mitochondria. Moreover, transmission electron microscopy showed that intracameral irrigation of Ala-Gln reversed the ultrastructural changes induced by the acute ocular hypertension in mice. Our study demonstrates that the intracameral irrigation of Ala-Gln effectively maintained the corneal endothelial pump function and barrier function by protecting the mitochondrial function and preventing the rearrangement of cytoskeleton in acute ocular hypertension in mice.

Mitochondrial ROS in Slc4a11 KO Corneal Endothelial Cells Lead to ER Stress

“…In addition to glucose, glutamine has been established as an important metabolite used by corneal endothelium ( Zhang et al, 2017a ; Zhang et al, 2017b ; Ogando et al, 2019 ; Hamuro et al, 2020 ; Jin et al, 2020 ; Ogando and Bonanno, 2022 ). Moreover, the high expression of Slc4a11 in mitochondria of corneal endothelial cells reduces glutamine-induced generation of superoxide and oxidative damage ( Ogando et al, 2019 ).…”

Pathogenic Role of Endoplasmic Reticulum Stress in Diabetic Corneal Endothelial Dysfunction

“…Acute high intraocular pressure (IOP) has transient deleterious effects on corneal endothelial cells. 27 Before the high IOP model was established, the mice were anesthetized with 50 mg/kg body weight pentobarbital through intraperitoneal injection. After maintaining pupil dilation with tropicamide (Akorn Pharmaceuticals, Lake Forest, IL, USA) and achieving corneal analgesia using eyedrops containing 0.5% proparacaine hydrochloride ophthalmic solution (Alcaine; Alcon, Fort Worth, TX, USA), a 34-gauge microsyringe needle (JBP Korea, Seoul, Korea) was introduced into the anterior chamber through the corneal tunnel, avoiding contact with the corneal endothelium and the lens.…”

“…The needle was connected to a 500-mL container of sodium chloride solution, and this solution was infused for 30 minutes. 27 Intraocular pressure was increased and maintained at 60 mmHg by elevating the solution container. At 0, 2, and 10 days after the termination of perfusion, all of the mice were examined.…”

Ethyl Acetate Extract of Selaginella doederleinii Hieron Induces Cell Autophagic Death and Apoptosis in Colorectal Cancer via PI3K-Akt-mTOR and AMPKα-Signaling Pathways

“…The samples were embedded in epoxy resin, sectioned (60-70 nm), and placed on formvar and carbon-coated copper grids. These grids were stained with uranyl acetate and lead citrate, and images were obtained using a transmission electron microscope (FEI, TECNAI G 2 , USA) (Jin et al, 2020).…”