الفهرس 
Submandibular salivary glandOnly 14 pages are availabe for public view
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Abstract
The present study was carried out to assess the effect of SMD ligation on Albino’s rat SMG with inclusion of the chorda tympani nerve, investigate if the impaired microscopic structure of SMG after parasympathetic denervation was either reversible or irreversible, and to compare the therapeutic effect of locally injected BM-MSCs versus PRP on regeneration of SMG after duct deligation. A total 80 adult male albino rats aged between 8- 10 weeks (200-250 grams) were used in this study. BM-MSCs were isolated from 10 rats and PRP were isolated from other 10 rats. The remaining 60 rats were subjected to extra oral right SMD ligation then had been deligated after two weeks. Afterward, the animals were randomly divided into one control group and two experimental groups each one contained 20 rats. group I (positive control group):- Rats in this group were subjected to SMD ligation for two weeks and were left without any treatment after ligation. Also, they were subjected to IG injection with 1 ml sterile physiological saline at the time of deligation to control the influence of injection stress in the experimental groups. group II (BM-MSCs treated group):- Rats in this group were subjected to SMD ligation for two weeks and treated with IG injection of isolated BM-MSCs solution at the time of deligation. group III (PRP treated group):- Rats in this group were subjected to SMD ligation for two weeks and treated with IG injection of isolated PRP solution at the time of deligation. • Left SMGs in each group were used as negative control for each experimental counterpart. Then, SMG tissues were evaluated histologically at days zero, 3, 7, and 14 from deligation respectively. The tissue investigations were done under LM using H&E and MT stains to evaluate regeneration of parenchymal elements and collagen fibers respectively. Also, IHC staining was performed using anti-PCNA in order to measure the proliferation index of acinar and ductal cells using image J software. In addition, the gland tissues were investigated under TEM to evaluate the ultra-structural changes of the SMG. Qualitatively both LM and TEM results of the left unligated SMGs (- ve control) showed almost normal histological appearances for all groups In positive control group, both LM and TEM results of right SMGs revealed marked degenerative changes persisted on all follow up periods. The severity of these changes was increased gradually from day zero to 14. Also, signs of nerve and SCs degenerations were appeared with TEM examination in all follow up periods of right SMG. In stem cell group, both LM and TEM results of right SMGs revealed obvious regeneration of SMG tissues at all follow up periods commencing from day 3 to 14 after duct deligation and local BM-MSCs administration. Initially, under LM using H&E stain there were noticeable recoveries in parenchymal elements at days 3, 7, and 14 after treatments. SMG showed definite architecture and almost normal acinar and ductal structure with few degenerative changes still persisted as cytoplasmic vacuolization and cellular apoptosis. Equally, MT stain depicted, at all follow up periods, CT capsule with almost normal structure. Besides, at day 7 CT capsule appeared thick and contained enlarged blood vessels. At day 14 CT capsules with inflammatory cells infiltrate could be portrayed. Also, collagen fibers in CT stroma depicted normal thickness and course. Interestingly, High endothelial venules were appeared clearly in CT stroma at all follow up periods. Likewise, nerve axon and SCs showed almost normal appearances under TEM. In PRP group, both LM and TEM results of right SMGs revealed clear regeneration of SMG tissues especially at follow up periods 7 and 14 after duct deligation and local PRP administration. Under LM using H&E stain at day 3 after duct deligation and PRP injection SMG still showed lobar atrophy and loss of normal acinar architecture. On the other hand, at days 7 and 14 after treatments there were noticeable recoveries in parenchymal elements. Also, SMG showed definite architecture and almost normal acinar and ductal structure with few degenerative changes still persisted as cytoplasmic vacuolization and widening of inter acinar space. Interestingly, branched tubules were appeared at days 7 and 14. Also, large endothelial venules near SD were detected at day 14. Similarly, MT stain at day 3 after duct deligation and PRP injection SMG depicted thin CT capsule, thick CT septa, and coarse collagen fibers in CT stroma. Nevertheless, at day 7 almost normal structures of CT capsule, septa, and stroma were depicted. Besides, at day 14 thick CT capsule with inflammatory cells infiltrate could be described. Also, collagen fibers in CT stroma depicted normal thickness and course with increased vascularity. Similarly, nerve axon and SCs showed almost normal appearances especially at day 14 under TEM. The statistical results of immunohistochemical PCNA expression supported the obtained histological results. By way of, our statistical analysis showed that regeneration rates in both the acinar and the ductal cells of the left SMGs (-ve control) had no significant difference (P. value > 0.05) between the four follow up periods in all groups. Moreover, we found that regeneration rates in aciner cells at the right SMGs (ligated) has differences with the highly significant regeneration rates present in stem cell group (P. value < 0.001) especially at day 7 followed by PRP group with significant difference (P. value < 0.05) and the least one in control group with no significant difference (P. value > 0.05). Besides, days 3 and 7 have the highly significant regeneration rates (P. value < 0.001) between the four follow up periods in all groups followed by day 14 with significant difference (P. value < 0.05). Nevertheless, we found that in duct cells in the right SMGs there were high regeneration rates with no significant difference (P. value > 0.05) between the four follow up periods in all groups.