Cell and Tissue Journal

Abstract  
Aim: Optimizing cell culture conditions to improve oocyte growth and maturation in vitro culture conditions has been the focus of many researchers today, but the quality improvement mechanism is not fully understood. Apoptosis or programmed cell death is a process to remove old and damaged cells from tissues and plays a major role in the life of follicles and immature oocytes. Most of the defective reproductive cells as well as extra cells are removed from the ovaries through apoptosis. One of the ways to reduce oxidative stress in the laboratory culture of oocyte maturation is the use of antioxidants. Statins are drugs for the treatment of high cholesterol for which antioxidant and anti-apoptotic properties have been reported. Atorvastatin in high doses has side effects for the heart and kidneys, but in low concentrations, it has antioxidant and anti-inflammatory effects for cells, and no side effects have been reported for it.In this study, we investigated the effect of low-dose atorvastatin on the rate of apoptosis in mouse oocytes.
 
Materials and Method: 24 h after PMSG (Pregnant Mare Serum Gonadotropin) inhection, 200 oocytes were obtained from adult female Wistar rats at the age of 4-5 weeks, were from were divided into 2 groups of 100 including the control group (MEM:Minimum Essential Medium culture+ Growth factor) and the atorvastatin group (MEM culture medium + 2 mg/kg atorvastatin+Growth factor) and cultured in the incubator(35 ^oC,CO2 %). After 24 hours of oocyte culture, Matured oocytes that met the standards of a healthy mature oocyte(oocytes that were in the first meiosis and had the first and mature polar body) were isolated the amount of apoptosis in each group was checked using tunnel staining and fluorescent microscope, the data were analyzed by variance analysis.
Results: After 24 hours of oocyte culture, the amount of apoptosis in the group receiving atorvastatin in the culture medium and the control group was investigated. The rate of apoptosis in the atorvastatin group and the control group was 24% and 22%, respectively, In the atorvastatin group, apoptosis increased by 2% compared to the control group butt the difference between the two groups was not statistically significant (p =0.11).
Conclusion: According to the findings of this study, atorvastatin in low doses can have a pro-apoptotic effect and cause partial induction of apoptosis in mouse oocytes in a laboratory environment. Although this study was not conducted on other doses of atorvastatin, it is suggested that the effect of other doses of this drug on the rate of apoptosis induction should be investigated in order to make an evidence-based decision regarding its administration and use.
 

Abstract Aim: Movement of water across cellular membranes is facilitated by the presence of water channels named aquaporins (AQPs). Mercurial compounds are potent blockers of plant and animal aquaporins. However some aquaporin isoforms such as NtAQP1 in tobacco are mercury-insensitive. The aim of this research was to determine the sensitivity of tobacco NtPIP2;1 to mercury.
Materials and methods: In this experimental study, after invitro transcription of NtPIP2;1 and cRNA synthesis, cRNA was injected to Xenopus oocytes by microinjection. Two days after incubation, oocytes were subjected to 1 mM mercury chloride for 10 min. Then, oocyte volume swelling assay in hypotonic medium was conducted and the membrane osmotic water permeability coefficient (Pf ) was determined.
Results: Pf for control and mercury chloride-treated oocytes expressing NtPIP2;1 was respectively calculated 0.99×10^-2 and 0.98×10^-2 cm s^-1 , which was not significant (P>0.05). Comparing the amino acid sequence of NtPIP2;1 with NtAQP1, a mercury-insensitive aquaporin, revealed the similar to  NtAQP1 replacement of cys with Thr in 233 position near the aquaporin pore in NtPIP2;1.
Conclusion: NtPIP2;1 encodes a mercury-insensitive aquaporin in tobacco which could be due to cysteine replacement with threonin near the aquaporin pore.