Effects Of Progesterone Administration On Cognitive Capability And The Research Of Relationship On The Expression Of Astrocytes In Mice

PURPOSEIn the current study we investigated whether a long-term progesterone(PROG) injection could have beneficial effects in promoting the learning and memory capability in ovariectomized mice. In addition, we also made a detection of some biochemical indicators which is related to the cognitive impairment of the learning and memory capability and the analyses of GFAP in the parietal lobe tissue to determine if PROG have a neuroprotective effect in ovariectomized mice.METHODSPART 1:60 female Kunming mice served as sham control or received bilateral ovariectomy followed by a 90-day regimen of different PROG (50mg/kg, 100mg/kg, 200mg/kg, respectively) or normal saline (10ml/kg) beginning 2 weeks after ovariectomy operation, PROG injections was given once per 5 days by intraperitoneal injection. At the end of the administration, we test the cognitve capability of acquisition and retrieval of an avoidance learning task using Y-maze. PART 2:After the cognitve capability performance of mice, we executed them all and took out the total brain tissue; some of them were used for determining the levels and variety of the GFAP in the parietal lobe tissue.RESULTSPART 1:THE RESULTS OF THE TEST ON THE COGNITIVE CAPABILITY OF LEARNING AND MEMORY CAPABILITY IN EACH GROUP1. The main results of Y-maze behavior examination are as follows:After the performance of the acquisition and retrieval of an avoidance learning task using Y-maze, compared with the Sham control group, the ovariectomized (OVX) group has low correct trials in the stage of acquisition and retrieval (P<0.05); compared with the OVX group, the correct trials in high-dose progesterone treated (HP) group is higher (P<0.05) in the stage of retrieval; these indicate that HP can enhance the avoidance learning capability in ovariectomized mice.PART 2:THE RESULT OF PROG'S EFFECTE ON THE ASTROCYTES IN PARIETAL LOBE TISSUE.1.The results of measure in GFAP:In measuring the GFAP of the mice, compared with the SHAM group, there were obvious increase in the expression level of the AOD and positive cell area of the OVX group (P<0.05), compared with the OVX group, there were decrease in the expression level of the AOD and positive cell area of the MP group and the HP group(P<0.05).Conclusion1. Deficiency of estrogen and progesterone can cause a descent in cognitive capability in adult female mice, which can be retrieved by a long-term regimen of progesterone (200mg/kg).2. In our study, we have found the beneficial effects of PROG in promoting the cognitive capability in ovariectomized mice have the phase's property.3. The possible mechanism of action from PROG in promoting the cognitive apability in ovariectomized maybe attributed to the regulation capacity to the astrocytes in the patietal lobe tissue, we found that PROG can protect the astrocytes by regulating its neurites'quantity and proliferation of the soma in astrocytes itself.4.There is a correlative relationship among progesterone, cognition and the expression of GFAP.