Effects of the secretome of human Wharton's jelly mesenchymal stem cells on the proliferation and apoptosis gene expression of the retinal pigmented epithelium.

ABSTRACT

Human retinal pigmented epithelium (RPE) can undergo an uncontrolled proliferation in some disorders such as retinal detachment associated with proliferative vitreoretinopathy (PVR). The present study was conducted to evaluate the effect of the conditioned medium secreted by human Wharton's jelly mesenchymal stem cells (WJMSCs-CM) on the proliferation and apoptosis gene expression of the RPE. WJMSCs-CM was collected from WJMSCs after two periods of 24-h and 9-h culture in serum-free medium. RPE cells were cultured in WJMSCs-CM versus serum-deprived media for 24 h. The effect of WJMSCs-CM on RPE cell proliferation was determined using the MTT assay. Relative expression of apoptotic genes (Bcl2, Bax, and IL-1B) was also assessed by real-time PCR. MTT assay demonstrated that RPE cell viability was reduced significantly in WJMSCs-CM treated RPE cells compared to those cultured in serum-deprived medium (64.23 ± 2.44 vs 100.10 ± 5.68; P = 0.006). Moreover, the expression of anti-apoptotic Bcl2 was significantly decreased in WJMSCs-CM compared to serum-deprived medium (0.52 ± 0.06 in WJMSCs-CM vs 1.02 ± 0.2 in serum-free treatment; P = 0.03), while the expression of pro-apoptotic biomarkers of Bax and IL-1B was not significantly different between the two treatments. The represented data showed that WJMSCs-CM can induce apoptosis in RPE cells in vitro through activating apoptosis pathways. This proof-of-the-concept study provides basic evidence for the possible effect of WJMSCs-CM on preventing PVR.