In treating glucocorticoids induced osteoporosis in temporomandibular joint of albino rats; which are more effective Microvesicles or Mesenchymal stem cells?

Background: Osteoporosis is a systemic skeletal disorder that increases bone fragility and risk of fractures.Current medications for treating osteoporosis are associated with osteonecrosis due to their anti-angiogenic effect that leads to ischaemic and necrotic changes.Aim: The present research compared two new approaches in treating glucocorticoids induced osteoporosis in temporomandibular joints (TMJs) of albino rats; Microvesicles (MVs) and Mesenchymal stem cells (MSCs).Materials and Methods: 39 adult female albino rats were divided into 3 groups.All rats were intraperitoneally injected once daily throughout the experimental period (60 days); 13 rats with 9% saline and 26 rats with dexamethasone (200µg/100 g body weight).After 30 days; the first group (control group) received a local injection of 1 ml PBS in TMJs of both sides.Half the dexamethasone injected rats were locally injected in the right side TMJs with 1x10 7 /ml/week MVs (Microvesicles group).The remaining rats (Stem cells group) received 1 million MSCs/ ml/week.In the later 2 groups, the left side TMJs received 1 ml PBS injection (untreated sides).The osteogenic potential was examined histologically, by western blotting, ELISA and RT-PCR.Results: Histologically; both sides from MSCs group exhibited abnormal configuration of the joint's anatomy while a marked improvement of bone architecture in the microvesicles treated TMJs was detected.Treated sides in both groups (MVs, MSCs) showed a significant increase in osteogenic markers (ALP, BMP and RUNX-2) and a decrease in inflammatory markers (IL-1β, TNF-α, IL-6) as well as in RANKL expression as compared to untreated ones.Conclusion: Microvesicles treated TMJs showed an enhanced pattern of bone regeneration confirmed by the higher mean bone area % as compared to MSCs group.On the contrary, MSCs treated TMJs showed a significantly elevated level of osteogenic markers; yet the osteogenic reactivity was very aggressive that caused deformity to the TMJ architecture.