Recovering Spermatogenesis By Protected Cryopreservation Using Metformin and Transplanting Spermatogonial Stem Cells Into Testis in an Azoospermia Mouse Model

Cryopreservation and transplantation of spermatogonial stem cells (SSCs) may serve as a new method to restore male fertility in patients undergoing chemotherapy or radiotherapy. However, SSCs may be damaged during cryopreservation due to the production of reactive oxygen species (ROS). Therefore, different antioxidants have been used as protective agents. Studies have shown that metformin (MET) has antioxidant activity. The aim of this study was to assess the antioxidant and antiapoptotic effects of MET in frozen-thawed SSCs. In addition, the effect of MET on the proliferation and differentiation of SSCs was evaluated. To this end, SSCs were isolated from mouse pups aged 3-6 days old, cultured, identified by flow cytometry (ID4, INTEGRIN β1+), and finally evaluated for survival and ROS rate. SSCs were transplanted after busulfan and cadmium treatment. Cryopreserved SSCs with and without MET were transplanted after 1 month of cryopreservation. Eight weeks after transplantation, the recipient testes were evaluated for the expression of apoptosis (BAX, BCL2), proliferation (PLZF), and differentiation (SCP3, TP1, TP2, PRM1) markers using immunohistochemistry, Western blot, and quantitative real-time polymerase chain reaction. The findings revealed that the survival rate of SSCs was higher in the 500 μm/mL MET group compared to the other groups (50 and 5000 μm/mL). MET significantly decreased the intracellular ROS production. Transplantation of SSCs increased the expression level of proliferation (PLZF) and differentiation (SCP3, TP1, TP2, PRM1) markers compared to azoospermia group, and their levels were significantly higher in the MET group compared to the cryopreservation group containing basic freezing medium (p < 0.05). MET increased the survival rate of SSCs, proliferation, and differentiation and decreased the ROS production and the apoptosis rate. Cryopreservation by MET seems to be effective in treating infertility.

Remote ischemic preconditioning combined with atorvastatin improves memory after global cerebral ischemia-reperfusion in male rats

Introduction: Damage to hippocampus can occur through ischemia. Memory problems are among the most significant disabilities after stroke. Therefore, improving memory is of great interest in helping post-stroke patients. This study demonstrated that intraperitoneally injection of atorvastatin with a short cycle of ischemia-reperfusion in the left femoral artery improved hippocampal CA1 neurons injury and memory problems after global cerebral ischemia.

Materials and methods: In this article survey, we used 64 animals. Rats were divided into 8 groups, (n=8). Group 1: control; group 2: sham; group 3: global cerebral ischemia (GCI) only; group 4: remote ischemic preconditioning (RIP) + GCI; group 5: GCI + atorvastatin (ATO); group 6: GCI + vehicle; group 7: RIP + GCI + ATO; group 8: RIP + GCI + vehicle. We created global cerebral ischemia (GCI) with 20 min occlusion of the Common carotid artery.

Results and discussion: Remote ischemic preconditioning could improve rats performance in water maze tests along with a decrease in neuronal death. Also, atorvastatin combined with remote ischemic preconditioning was more effective for memory improvement and reduction of neuronal death. Inconsistent with our result, the function of the animals in the ischemia group was impaired. CA1 hippocampal neurons have an important role in memory and learning, and they can be damaged after cerebral ischemia. Therefore, ischemia can create memory problems. Remote ischemic preconditioning and atorvastatin had a neuroprotective effect and could improve rat performance in water maze test.

Conclusion: This study showed that remote ischemic preconditioning with atorvastatin could improve CA1 neuronal injury and memory.

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