RESUMO
BACKGROUND: The efficacy of mesnchymal stem cells (MSCs) to treat the necrotic tissue of salivary glands (SGs) has yet investigated. OBJECTIVE: This study was conducted to investigate the potential capacity of MSCs to restore the function and regenerate the necrotic submandiular gland in the rat animal model. METHODS: Twenty-one Sprague-Dawley rats were provided from a breeding colony and randomly divided into three groups including the positive control or induced SG atrophy without treatment, the treatment group or induced SG atrophy with MSCs isolated transplantation and the negative control group consists of healthy rats. The atrophic and necrotic submandiular gland was induced using intraoral duct ligation of the main duct of submandiular gland for one month. The isolated stem cells were confirmed using flow cytometry for CD90 and CD 105. The isolated MSCs were cultured and injected to submandiular gland and the potential efficacy of MSCs to treat the atrophic submandibular glands was evaluated using histopathology on two weeks post-transplantation. To detect the acinar cell protein secretory granules, Alcian Blue and periodic acid shift (PAS) staining were done. For the demonstration of mitotic index or proliferation rate of the SG epithelia tissue, Ki-67 and Smbg proteins expression were evaluated using immunohistochemistry. RESULTS: The locally injected MSCs could regenerate the overall histological structure of the necrotic submandibular gland tissue within 2 weeks of post-transplantation. Alcian Blue and PAS staining indicated that the mean amount of serous and mucin secretions in the treatment group was significantly increased compared to the positive control groups. We have also found that the treatment group significantly express higher Ki-67 protein, as a diagnostic marker for cell mitosis and proliferation rate, and lower Smbg protein, as a diagnostic marker, for damage to the submandibular gland than that of control group. CONCLUSION: This study demonstrates the therapeutic benefits of MSCs isolated from the SG in treating atrophic and necrotic SGs in a rat model. MSCs may be potential candidates for cell-based therapies targeting hypofunction of SG induced by a range of diseases or because of surgery and radiotherapy of head and neck cancers.
RESUMO
The purpose of the present paper is improving the accuracy of existing formulas for the longitudinal dispersion coefficient (LDC) prediction based on a novel and simple meta-heuristic optimization method called Whale Optimization Algorithm (WOA). Although several existing formulas calculate LDC in the rivers based on the hydraulic and hydrodynamic specifications, most of them have significant errors in confronting extensive field data. In this study, comprehensive field data, including the geometrical and hydraulic properties of different rivers in the world, were adopted to build a reliable model. Statistical error measures were used to evaluate and compare the results with other studies. Furthermore, the Subset Selection of Maximum Dissimilarity (SSMD) method was utilized for a reputable selection of data for training and testing the WOA model. Subset selection is a critical factor in artificial intelligence (AI) computations. Finally, an integrated model based on the SSMD method and WOA technique has been proposed to develop the high accuracy formulas for the prediction of LDC. According to the results, the developed formulas are competitive or superior to the previous formulas for LDC estimation. Results also indicated that the WOA algorithm could be applied to improve the performance of the predictive equations in other fields of studies by finding the optimum values of coefficients.