Role of Chlamydia trachomatis intraocular infection in the development of proliferative vitreoretinopathy (experimental study)

Abstract

To study the influence of C. trachomatis infection on proliferative vitreoretinopathy (PVR) stimulation and development in an experimental model. Intravitreal C. trachomatis injection was performed in 17 rabbits (right eyes) out of which 8 developed minimal chlamydial damage (1 was further subjected to histopathological examination with pathogen detection in ocular structures and other 7 were included in the study group). The control group consisted of 7 rabbits with no laboratory evidence of chlamydial infection. PVR was induced by 4 peripheral retinal punctures with a 19 G needle. Follow-up methods included ophthalmoscopy, ultrasonography, and PVR grading according to the Fastenberg classification. Histopathological examination, supplemented with pathogen detection by direct immunofluorescence in the study group, was performed at weeks 7 and 20. PVR rate and severity were higher in the study group as compared with the controls (5 out of 7 rabbits, grade 2-4 vs. 2 out of 7 rabbits, grade 0-1, p<0.01). In the study group, histopathological examination performed before and after the induction of PVR revealed a pronounced lymphocyte and macrophage infiltration, characteristic of infectious inflammation. Similarly, extra- and intracellular chlamydial inclusions could be found in the retina and/or zones of proliferation throughout the whole study period. Inflammation signs (including those of proliferation) were reliably less significant in the controls. C. trachomatis infection of the posterior segment contributes to PVR development due to associated chronic inflammation.