Ultrastructure and 3D transmission electron tomography of collagen fibrils and proteoglycans of swollen human corneal stroma

Saeed Akhtar, G. Petrovski, R. Albert, A. Alkanaan, O. Kirat, A. D. Khan, T. Almubrad

Research output: Contribution to journalArticle

Abstract

Background. The transparency of the cornea is regulated by the unique organization of collagen fibrils (CFs) which is maintained by proteoglycans (PGs). The interlacing of CF lamellae in the anterior stroma provides the biomechanical properties of the cornea. Objective. To investigate the alterations of CFs and PGs in the swollen cornea, with special reference to the anterior stroma by using electron microscopy and 3D ultrastructural tomography. Method. Nine healthy normal scleral corneal rings (age from 40 to 65 years) were hydrated individually in deionised water to induce swelling in the cornea. Three of them were hydrated for 2hr whereas the other three were hydrated for 48hr. The remaining three scleral normal corneal rings were used as a control.The corneas were processed for electron microscopy (E M) to study the CFs and PGs. Ultrathin sections were observed using transmission electron microscopy (JOEL 1400) and digital images of CFs, PGs and lamellae were captured using a bottom mounted Quemesa camera and iTEM Soft Imaging System. The software program ‘Composer-x64, version 3.4.2.0’ was used to construct individual 3D images from 120 digital images taken from-60 to +60 degree angles. Results. The 3D tomography showed the degeneration of microfibrils within the CFs of the swollen cornea. The CF diameter was significantly reduced and the interfibrillar spacing significantly increased in both the 2hr and 48hr hydrated corneas compared to the normal cornea. Within the hydrated corneas, the CF diameter was smaller and the interfibrillar spacing was increased in the middle and posterior stroma compared to the anterior stroma. The PG area in both the 2hr and the 48hr hydrated cornea was reduced in the anterior stroma, whereas it was increased in middle and posterior stroma compared to the normal cornea. The density of the PGs in both the 2hr and the 48hr samples, was reduced compared to the density of PGs in the normal cornea. Conclusion. The CFs, PGs and lamellae had degenerated, caused by swelling. 3D imaging demonstrated that the impairment of the microfibrils and PGs within the CF, is caused by the excessive hydration or swelling in the anterior as well as in the middle and posterior stroma. The lamellae of the anterior stroma which provides the biomechanical strength in the normal cornea, had degenerated in the swollen corneas due to the presence of the damaged CFs and PGs.

Original languageEnglish
Pages (from-to)91-102
Number of pages12
JournalHistology and Histopathology
Volume34
Issue number1
DOIs
Publication statusPublished - Jan 1 2018

Fingerprint

X Ray Tomography
Electron Microscope Tomography
Corneal Stroma
Proteoglycans
Cornea
Collagen
Microfibrils
Electron Microscopy
Tomography

Keywords

  • 3D image
  • Collagen fibrils
  • Microfibrils
  • Proteoglycans
  • Swelling
  • Tomography

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology

Cite this

Ultrastructure and 3D transmission electron tomography of collagen fibrils and proteoglycans of swollen human corneal stroma. / Akhtar, Saeed; Petrovski, G.; Albert, R.; Alkanaan, A.; Kirat, O.; Khan, A. D.; Almubrad, T.

In: Histology and Histopathology, Vol. 34, No. 1, 01.01.2018, p. 91-102.

Research output: Contribution to journalArticle

Akhtar, Saeed ; Petrovski, G. ; Albert, R. ; Alkanaan, A. ; Kirat, O. ; Khan, A. D. ; Almubrad, T. / Ultrastructure and 3D transmission electron tomography of collagen fibrils and proteoglycans of swollen human corneal stroma. In: Histology and Histopathology. 2018 ; Vol. 34, No. 1. pp. 91-102.
@article{d9d7e6ebb47c4dd8a373f9f791b92acd,
title = "Ultrastructure and 3D transmission electron tomography of collagen fibrils and proteoglycans of swollen human corneal stroma",
abstract = "Background. The transparency of the cornea is regulated by the unique organization of collagen fibrils (CFs) which is maintained by proteoglycans (PGs). The interlacing of CF lamellae in the anterior stroma provides the biomechanical properties of the cornea. Objective. To investigate the alterations of CFs and PGs in the swollen cornea, with special reference to the anterior stroma by using electron microscopy and 3D ultrastructural tomography. Method. Nine healthy normal scleral corneal rings (age from 40 to 65 years) were hydrated individually in deionised water to induce swelling in the cornea. Three of them were hydrated for 2hr whereas the other three were hydrated for 48hr. The remaining three scleral normal corneal rings were used as a control.The corneas were processed for electron microscopy (E M) to study the CFs and PGs. Ultrathin sections were observed using transmission electron microscopy (JOEL 1400) and digital images of CFs, PGs and lamellae were captured using a bottom mounted Quemesa camera and iTEM Soft Imaging System. The software program ‘Composer-x64, version 3.4.2.0’ was used to construct individual 3D images from 120 digital images taken from-60 to +60 degree angles. Results. The 3D tomography showed the degeneration of microfibrils within the CFs of the swollen cornea. The CF diameter was significantly reduced and the interfibrillar spacing significantly increased in both the 2hr and 48hr hydrated corneas compared to the normal cornea. Within the hydrated corneas, the CF diameter was smaller and the interfibrillar spacing was increased in the middle and posterior stroma compared to the anterior stroma. The PG area in both the 2hr and the 48hr hydrated cornea was reduced in the anterior stroma, whereas it was increased in middle and posterior stroma compared to the normal cornea. The density of the PGs in both the 2hr and the 48hr samples, was reduced compared to the density of PGs in the normal cornea. Conclusion. The CFs, PGs and lamellae had degenerated, caused by swelling. 3D imaging demonstrated that the impairment of the microfibrils and PGs within the CF, is caused by the excessive hydration or swelling in the anterior as well as in the middle and posterior stroma. The lamellae of the anterior stroma which provides the biomechanical strength in the normal cornea, had degenerated in the swollen corneas due to the presence of the damaged CFs and PGs.",
keywords = "3D image, Collagen fibrils, Microfibrils, Proteoglycans, Swelling, Tomography",
author = "Saeed Akhtar and G. Petrovski and R. Albert and A. Alkanaan and O. Kirat and Khan, {A. D.} and T. Almubrad",
year = "2018",
month = "1",
day = "1",
doi = "10.14670/HH-18-029",
language = "English",
volume = "34",
pages = "91--102",
journal = "Histology and Histopathology",
issn = "0213-3911",
publisher = "Histology and Histopathology",
number = "1",

}

TY - JOUR

T1 - Ultrastructure and 3D transmission electron tomography of collagen fibrils and proteoglycans of swollen human corneal stroma

AU - Akhtar, Saeed

AU - Petrovski, G.

AU - Albert, R.

AU - Alkanaan, A.

AU - Kirat, O.

AU - Khan, A. D.

AU - Almubrad, T.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Background. The transparency of the cornea is regulated by the unique organization of collagen fibrils (CFs) which is maintained by proteoglycans (PGs). The interlacing of CF lamellae in the anterior stroma provides the biomechanical properties of the cornea. Objective. To investigate the alterations of CFs and PGs in the swollen cornea, with special reference to the anterior stroma by using electron microscopy and 3D ultrastructural tomography. Method. Nine healthy normal scleral corneal rings (age from 40 to 65 years) were hydrated individually in deionised water to induce swelling in the cornea. Three of them were hydrated for 2hr whereas the other three were hydrated for 48hr. The remaining three scleral normal corneal rings were used as a control.The corneas were processed for electron microscopy (E M) to study the CFs and PGs. Ultrathin sections were observed using transmission electron microscopy (JOEL 1400) and digital images of CFs, PGs and lamellae were captured using a bottom mounted Quemesa camera and iTEM Soft Imaging System. The software program ‘Composer-x64, version 3.4.2.0’ was used to construct individual 3D images from 120 digital images taken from-60 to +60 degree angles. Results. The 3D tomography showed the degeneration of microfibrils within the CFs of the swollen cornea. The CF diameter was significantly reduced and the interfibrillar spacing significantly increased in both the 2hr and 48hr hydrated corneas compared to the normal cornea. Within the hydrated corneas, the CF diameter was smaller and the interfibrillar spacing was increased in the middle and posterior stroma compared to the anterior stroma. The PG area in both the 2hr and the 48hr hydrated cornea was reduced in the anterior stroma, whereas it was increased in middle and posterior stroma compared to the normal cornea. The density of the PGs in both the 2hr and the 48hr samples, was reduced compared to the density of PGs in the normal cornea. Conclusion. The CFs, PGs and lamellae had degenerated, caused by swelling. 3D imaging demonstrated that the impairment of the microfibrils and PGs within the CF, is caused by the excessive hydration or swelling in the anterior as well as in the middle and posterior stroma. The lamellae of the anterior stroma which provides the biomechanical strength in the normal cornea, had degenerated in the swollen corneas due to the presence of the damaged CFs and PGs.

AB - Background. The transparency of the cornea is regulated by the unique organization of collagen fibrils (CFs) which is maintained by proteoglycans (PGs). The interlacing of CF lamellae in the anterior stroma provides the biomechanical properties of the cornea. Objective. To investigate the alterations of CFs and PGs in the swollen cornea, with special reference to the anterior stroma by using electron microscopy and 3D ultrastructural tomography. Method. Nine healthy normal scleral corneal rings (age from 40 to 65 years) were hydrated individually in deionised water to induce swelling in the cornea. Three of them were hydrated for 2hr whereas the other three were hydrated for 48hr. The remaining three scleral normal corneal rings were used as a control.The corneas were processed for electron microscopy (E M) to study the CFs and PGs. Ultrathin sections were observed using transmission electron microscopy (JOEL 1400) and digital images of CFs, PGs and lamellae were captured using a bottom mounted Quemesa camera and iTEM Soft Imaging System. The software program ‘Composer-x64, version 3.4.2.0’ was used to construct individual 3D images from 120 digital images taken from-60 to +60 degree angles. Results. The 3D tomography showed the degeneration of microfibrils within the CFs of the swollen cornea. The CF diameter was significantly reduced and the interfibrillar spacing significantly increased in both the 2hr and 48hr hydrated corneas compared to the normal cornea. Within the hydrated corneas, the CF diameter was smaller and the interfibrillar spacing was increased in the middle and posterior stroma compared to the anterior stroma. The PG area in both the 2hr and the 48hr hydrated cornea was reduced in the anterior stroma, whereas it was increased in middle and posterior stroma compared to the normal cornea. The density of the PGs in both the 2hr and the 48hr samples, was reduced compared to the density of PGs in the normal cornea. Conclusion. The CFs, PGs and lamellae had degenerated, caused by swelling. 3D imaging demonstrated that the impairment of the microfibrils and PGs within the CF, is caused by the excessive hydration or swelling in the anterior as well as in the middle and posterior stroma. The lamellae of the anterior stroma which provides the biomechanical strength in the normal cornea, had degenerated in the swollen corneas due to the presence of the damaged CFs and PGs.

KW - 3D image

KW - Collagen fibrils

KW - Microfibrils

KW - Proteoglycans

KW - Swelling

KW - Tomography

UR - http://www.scopus.com/inward/record.url?scp=85060169213&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85060169213&partnerID=8YFLogxK

U2 - 10.14670/HH-18-029

DO - 10.14670/HH-18-029

M3 - Article

C2 - 30019745

AN - SCOPUS:85060169213

VL - 34

SP - 91

EP - 102

JO - Histology and Histopathology

JF - Histology and Histopathology

SN - 0213-3911

IS - 1

ER -