In vitro study on paired immunoglobulin-like receptor B regulating growth of retinal ganglion cells

Abstract

Objective To determine the effect of paired immunoglobulin-like receptor B (PirB) on growth of retinal ganglion cells (RGCs) in vitro.Methods Expression of PirB in RGCs isolated from wild-type C57 BJ/6 mice was measured by immunofluorescence.Real-time PCR and Western blot were performed to detect PirB expressions in RGCs cultured for 1,3,5,7 and 9 days.Primary cultured RGCs were left untreated as controls,transfected with lentiviral-delivered PirB RNAi as Group A,lentiviral-delivered NgR RNAi as Group B,lentiviral-delivered PirB RNAi plus ciliary neurotrophic factor (CNTF) as Group C,lentiviral-delivered NgR plus CNTF as Group D,and only CNTF as Group E.Growth and development of RGCs were evaluated by MTT assay and morphological analysis.Results Immunofluorescence confirmed expression of PirB in RGCs,with its mRNA and protein levels changing from increase at first to decrease later with time,up to peak at days 5 and 7.PirB and NgR were respectively down-regulated in Groups A and B.Viability of RGCs was improved in Group A compared with control group [(40.2 ± 5.3) μm vs (29.1 ± 3.8) μm at day 3 ; (72.2 ± 4.2) μm vs (52.3 ± 8.2) μm at day 5,both P ＜ 0.05].By contrast,no significant difference was found in viability of RGCs among Groups B,D and E when compared to control group (P ＞ 0.05).Growth of RGCs between Groups A and C revealed insignificant difference (P ＞ 0.05).Conclusion Knockdown of PirB is beneficial for the growth of RGCs,suggesting a novel method to treat optic nerve injury. Key words: Optic nerve; Retinal ganglion cells; Immunoglobulins