Analysis of microvessel density in pterygium tissue with corneal laser confocal microscopyc in vivo and immunohistochemistry in vitro / 中华实验眼科杂志

ABSTRACT

BackgroundPterygium is an ocular surface disease of abnormal cell proliferative kind and angiogenesis plays an important role in its development and recurrence.Several anti-angiogenic therapies have been used to treat pterygium,but there very few studtes for the in vivo observation of the microvessles in pterygium.ObjectiveThis study was to observe angiogenesis in pterygium with a high-resolution confocal microscope in vivo and to perform immunohistochemical study in vitro.MethodsA prospective case-controlled study was designed.Twenty eyes of 20 consecutive patients with primary pterygia and 20 age- and sex-matched patients with inner eye diseases and strabismus with normal conjunctiva were enrolled in this study.An in vivo confocal microscopy imaging system (Heidelberg Retina Tomograph Ⅱ Rostock Cornea Module) was used to collect microvascular pictures from the anterior part of pterygia and normal nasal conjunctiva of controls,and then immunochemistry was performed to examine the expression of CD31 in microvessel in vitro.The vascular density values were compared between these two groups.The correlation of vascular density values between in vivo Heidelberg Retina Tomograph and in vitro immunohistochemistry was calculated.Written informed consent was obtained from pationts before any examination and surgery.ResultsUnder the in vivo confocal microscope,the microvessel density was (8929±2993) μm/mm2 and (4202 ±692)μm/mm2,respectively,in pterygium and the normal conjunctiva group with a statistically significant difference between them (t =6.881,P＜0.01 ).Immunochemistry revealed that the expression of CD31 to measure vascular density was ( 21.00 ± 4.06/400 × field ) and ( 6.07 ± 1.75/400 × field ) in pterygium and the normal conjunctiva group,showing significant difference (t =12.312,P＜0.01 ).Positive correlations were found in the vascular density values between in vivo corneal laser confocal microscopy examination and in vitro immunochemistry examination in both the pterygium group and normal conjunctiva group (pterygium groupr=0.649,P＜0.01 ;normal conjunctiva group r=0.572,P＜0.01 ) ConclusionsIn vivo confocal microscopy imaging is superior to in vitro immunochemistry in evaluating the microvessel of pterygium.The results of this study offer a new way index for further investigation of the biological behavior of pterygium and its mechanism.