Lipid deposition and oxidized-low density lipoprotein in pterygium

Abstract

Purpose: Previous study has shown abnormal cholesterol metabolism and lipid peroxidation in pterygium, this study was to investigate whether lipid deposition and apolipoprotein peroxidation exist in pterygium.

Methods: Primary pterygium specimens were cut into two parts along the central long axis for frozen and paraffin embedding, respectively. Semi-quantitative reverse transcription-polymerase chain reaction ( RT-PCR ) and western blot ( WB ) were used to detect low density lipoprotein receptor ( LDL-R ), Lectin-like oxidized low density lipoprotein receptor-1 ( LOX-I ) and scavenger receptor that binds phosphatidylsedne and oxidized lipoprotein ( SR-PSOX ). Lipid staining( sudan black B and oil red O ), specific lipid extraction and filipin Ⅲ staining were used to investigate lipid deposition. Immunofluorescence (IF) or Immunohistochemistry ( IHC ) was used to apolipoprotein ( including APOA1, B and E ), malonaldehyde-low density lipoprotein ( MDA-LDL ), oxidized-low density lipoprotein ( OX-LDL ), LDL-R, LOX-1 and SR-PSOX.

Results: We found that lipid staining, filipin Ⅲ staining, APOA1 and APOE were positive in the head area of pteygium. MDA-LDL was positive in the whole pterygium tissue. OX-LDL was weak positive in the superficial parts of pterygium. LOX-1 was expressed in small amount of the samples. LDL-R and PS-OX was not expressed in pterygium.

Conclusions: Lipid, especially esterified cholesterol, APOA1, and APOE were deposited at head area of pterygium. Two different oxidized levels of LDL expressed in pterygium in different level. Lipid deposition and apolipoprotein peroxidation may be engaged in pterygium pathological progress.