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Background and Objective: Stem cells are a suitable treatment method for improvement of central nervous system diseases. Neuron regeneration is occure in damaged region using stem cell transplantation. This study was done to determine the effect of bone marrow mesenchymal stem cells on memory and neuronal cells graft number in the trimethyltin chloride damaged hippocampus. Methods: In this experimental study, 28 wistar male rats were allocated into four groups including control, model, Vehicle and treatment groups. Animals were received 8 mg/kg/bw of neurotoxin trimethyltin chloride by the intraperitoneal injection for causing damaged in hippocampus. One week after intraperitoneal injection of trimethyltin chloride, stem cells was injected by stereotaxy method. Six weeks after stem cells injection, the spatial memory was assessed by Morris water maze and histological studies were done by Nissl staining and normal cells count by Olysia bio report software. Results: After bone marrow mesenchymal stem cells graft, the number of normal cells were more in the treatment group (74±15.190) in compared to the Vehicle (44.67±12.971) and Model (48.56±18.105) groups (P<0.05). Also in Morris water maze test, the treatment group (387.35±189.18), (31.30±13.67) spent shorter distance and escape latency to reach the hidden platform, but this reduced non significantly in compared to Vehicle (438.18±192.56), (40.14±14.89) and model (407.98±225.44), (37.68±17.15) groups. The model and Vehicle groups spent longer distance to reach the hidden platform in comparision with the control (275.45±165.10) group (P<0.05). Also the traveled distance in target quarter had significant increased in the treatment groups (799.80±125.91) in compared to model (588.51±136.94) and Vehicle (546.48±86.47) groups (P<0.05). Conclusion: Using the bone marrow mesenchymal stem cells leads to reduce hippocampal lesions and increase the number of pyramidal neurons and improving memory in damaged hippocampus in animal model.

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Background and Objective: The emergence of Gram-positive and Gram-negative bacteria resistant to antibiotics is a crisis worldwide. In this study, the antibacterial effect of zinc oxide nanoparticles was evaluated on standard and food isolated strains of Salmonella enteritidis and Bacillus cereus.
Methods: This descriptive laboratory study, zinc oxide nanoparticles were prepared on zeolite materials, and zinc level was determined using XRF. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ZnO nanoparticles were determined using disc diffusion method.
Results: MIC value for all tested bacteria was 4 mg/ml and MBC values of standard and isolated strains of Salmonella enteritidis were 16 and 8 mg/ml, respectively, and for standard and isolated strains of Bacillus cereus was calculated in the range of 16 mg/ml.
Conclusion: Zinc oxide nanoparticles can inhibit Salmonella enteritidis and Bacillus cereus strains and may have a potential for its replacement with current preservatives to prevent food spoilage in industry.