This study aimed to evaluate the effect of mesenchymal stem cells (MSCs)–derived exosomes in retina regeneration of experimentally induced diabetes mellitus (DM) in a rabbit model. Exosomes are extracellular vesicles that contain many microRNAs (micRNAs), mRNAs, and proteins from their cells of origin. DM was induced by intravenous (IV) injection of streptozotocin in rabbits. MSCs were isolated from adipose tissue of rabbits. Exosomes were extracted from MSCs by ultracentrifugation. Exosomes were injected by different routes (IV, subconjunctival (SC), and intraocular (IO)). Evaluation of the treatment was carried out by histopathological examination of retinal tissues and assessment of micRNA-222 expression level in retinal tissue by real-time polymerase chain reaction. Histologically, by 12 weeks following SC exosomal treatment, the cellular components of the retina were organized in well-defined layers, while IO exosomal injection showed well-defined retinal layers which were obviously similar to layers of the normal retina. However, the retina appeared after IV exosomal injection as irregular ganglionic layer with increased thickness. MicRNA-222 expression level was significantly reduced in diabetic controls when compared to each of healthy controls and other diabetic groups with IV, SC, and IO routes of injected exosomes (0.06 ± 0.02 vs. 0.51 ± 0.07, 0.28 ± 0.08, 0.48 ± 0.06, and 0.42 ± 0.11, respectively). We detected a significant negative correlation between serum glucose and retinal tissue micRNA-222 expression level (r = −0.749, p = 0.001). We can associate the increased expression of micRNA-222 with regenerative changes of retina following administration of MSCs-derived exosomes. The study demonstrates the potency of rabbit adipose tissue–derived MSCs exosomes in retinal repair. So, exosomes are considered as novel therapeutic vectors in MSCs-based therapy through its role in shuttling of many factors including micRNA-222.

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Background: Regarding postmortem estimation, the evaluation of early histological and miRNA molecular changes have been of great concerns among forensic scientists due to uncertainty of known conventional methods. The histological and miRNA molecular changes in incisional wound remain poorly described. Purpose: This evaluation presents a histo-molecular approach that could be used to estimate the early post mortem interval in incisional wound. Methods: The histological and miRNA (205 and 21) changes were evaluated in 18 female albino rats with incisional wound at three interval times: 0, 24, and 48 h after infliction. Results: The wound margin showed progressive morphological changes with increasing postmortem interval. Inflammatory phase had appeared immediately after infliction. After this period, degenerative changes began. mRNA-205 and 21 expressions, detected via real-time PCR, were increased significantly to reach their higher levels at 24 h after wound infliction, then they were significantly diminished with increasing postmortem interval. Conclusions: Our results suggest that histological and miRNA-205 and miRNA-21 changes, occurred at perimortal incisional wound, could be helpful in forensic work regarding postmortem estimation.

Graphical abstract

Mesenchymal stem cells (MSCs) releases in culture extracellular vesicles called microvesicles (MVs). MVs have beneficial cytokines that prevent progression of the disease and help in the regeneration process. This study is aimed to evaluate the effect of MSCs derived MVs in repair of induced chondral defect in a dog model. Methods: Chondral defects were created surgically (3 mm  1 mm) in both femoral condyles of nine dogs, autologous MSCs were isolated and MVs were prepared and injected Correspondence to: intraarticularly in the right joint. The left joint was injected with normal saline as control negative. Evaluation of the treatment after first injection was carried out by physical examination and histopathology at different time periods (1½, 3 and 6 months). Results: Treated joints showed marked degree of cartilage regeneration and restoration of chondral histomorphological picture on the contrary of the control joints that showed deterioration over time and defect filling with only fibrous tissue forming a fibrocartilage at the end of six months period. Conclusion: We demonstrated in this study that administration of MVs was effective on the functional and morphological recovery of the injured cartilage and could be exploited as a cell free therapeutic approach in regenerative medicine.