| Stroke is a group of limited or comprehensive brain dysfunction syndrome caused by acute cerebral circulation disorder,including ischemic and hemorrhagic strokes.It has the characteristics of high incidence,high morbidity,high mortality and high recurrence rate,and brings about a heavy burden to the family and society.while acute ischemic stroke is the most common type of stroke,accounting for about 60 percent to 80 percent.The study of the protective effect of progesterone on the brain began in the 80s of last century.At present,the treatment for acute traumatic brain injury with progesterone has entered the phase III clinical trials,however,its untoward reactions limits its application and promoting.A large number of clinical practice and research confirmed that,traditional Chinese medicine has played a certain role in the treatment of ischemic stroke in clinics.Through the literature research and the preliminary research work in our team,baicalin of scutellaria baicalensis georgi can play a better role in protecting brain against ischemic brain injury,and it can improve the level of serum progesterone in pregnant mice.Thus,we put forward the hypothesis that the protective effect of baicalin on brain is related to the increase of serum progesterone level,and we have confirmed that the protective effect of baicalin on female rats with ischemic brain injury was related to the improvement of serum progesterone level in our preliminary work.In this study,we need to further clarify whether the protective effect of baicalin on male rats with ischemic brain injury is related to the improvement of serum progesterone level,and need to investigate the possible mechanism of baicalin in improving the serum progesterone level in male rats with ischemic brain injury,in order to lay the foundation for the research to develop a natural substitute drug for the treatment for ischemic brain damage which has a similar effect on progesterone.Objective1.To investigate the effect of baicalin on the serum progesterone level and the expression of progesterone receptor in brain tissue of normal male rats and rats with ischemic brain injury.2.To investigate the possible mechanism of baicalin in improving the serum progesterone level in male rats with ischemic brain injury.3.To investigate whether it is one of the mechanisms of brain protection for baicalin by improving the level of serum progesterone in male rats.Method1.The left permanent middle cerebral artery occlusion model(pMCAO model)in male rats with suture method was created,the model rats were evenly divided into model group and baicalin group according to the neurological function score,and normal group and normal +baicalin group were set.The rats were administered after successful modeling in 24hours,once a day.Rats in baicalin group and normal+baicalin group were given baicalin solution for intraperitoneal injection,while rats in model group and normal group were given isometric saline for intraperitoneal injection.Abdominal aortic blood and brain were taken out after modeling 7 days,detecting the serum progesterone level by ELISA,the expression of progesterone receptor in brain tissue was detected by immunohistochemistry.2.The left permanent middle cerebral artery occlusion model(pMCAO model)in male rats with suture method was created,the model rats were evenly divided into model group,baicalin group and Inhibitor group according to the neurological function score,and the sham operation group without inserting the intraluminal thread.The rats were administered after successful modeling in 24 hours,once a day.Rats in baicalin group were given baicalin solution for intraperitoneal injection and distilled water for gavage,rats in model group and sham operation group were given isometric saline for intraperitoneal injection and distilled water for gavage,and rats in inhibitor group were given baicalin solution for intraperitoneal injection and bromocriptine for gavage(in order to inhibit the production of progesterone).Abdominal aortic blood and renicapsule were taken out after modeling 7 days,the serum progesterone level and ACTH level were detected by ELISA,and the expression of P450 cholesterol side chain cleavage enzyme(P450scc)mRNA and 3beta-Hydroxysteroid dehydrogenase(3β-HSD)mRNA in renicapsule which were related to progesterone synthesis were detected by fluorescent quantitative PCR.3.The left permanent middle cerebral artery occlusion model(pMCAO model)in male rats with suture method was created,the model rats were divided into model group,baicalin group and inhibitor group according to the neurological function score,and the sham operation group without inserting the intraluminal thread(method of administration with 2).The neurological function score of sham operation group,model group,baicalin group and inhibitor group 2-4 hours,1 days,3 days and 7 days later after successful modeling were measured,the grip strength of double foreleg was measured before modeling the night before jejunitas and 1 days,3 days and 7 days later after successful modeling were measured,and the reduction rate of grip strength was calculated.The brain were taken out after modeling in 7 days,TTC staining was used to observe cerebral infarction,calculating the infarct volume percentage with image analysis software,and morphological change of brain tissue were observed by HE staining.Result1.The effects of baicalin on the serum progesterone level and the expression of progesterone receptor in brain tissue of normal male rats and rats with ischemic brain injury1.1 The level of serum progesterone:Compared with normal group,the level of serum progesterone in model group decreased(P<0.05).Compared with model group,the level of serum progesterone in baicalin group increased(P<0.05).1.2 The expression of progesterone receptor in brain tissue:Progesterone receptors are mainly expressed in the cytoplasm and nucleus of neurons in the cerebral cortex.Compared with normal group,the expression level of progesterone receptor in normal+baicalin group increased in the parietal cortex(P<0.05).Compared with model group,the expression level of progesterone receptor in baicalin group increased in the ischemic penumbra(P<0.05).2.The possible mechanism of baicalin in improving serum progesterone level in male rats with ischemic brain injury2.1 The level of serum progesterone:Compared with sham operation group,the level of serum progesterone in model group has a trend in decreasing(P>0.05),the level of serum progesterone in baicalin group increased(P<0.05).Compared with model group,the level of serum progesterone in baicalin group significantly increased(P<0.01).Compared with baicalin group,the level of serum progesterone in inhibitor group decreased(P<0.05).2.2 The level of serum ACTH:Compared with sham operation group,the level of serum ACTH in model group and baicalin group increased in different degrees(P>0.05 or P<0.01).Compared with model group,the level of serum ACTH in baicalin group has a trend in increasing(P>0.05).Compared baicalin group,the level of serum ACTH in inhibitor group decreased(P<0.05).2.3 The expression levels of P450scc mRNA and 3β-HSD mRNA in renicapsule:Compared with sham operation group,the expression of p450scc mRNA and 3β-HSD mRNA in renicapsule increased in model group,baicalin group and inhibitor group(P<0.05),but the expression of baicalin group increased significantly.3.Baicalin can improve the level of serum progesterone in male rats with ischemic brain injury which may be one of the mechanisms of brain protection3.1 Neurological function score:Compared with sham operation group,the neurological function of model rats in each group was impaired significantly,and the neurological function score increased.The neurological function score in model group has a trend in decreasing,and the nerve function was gradually restored.The recovery of nerve function in baicalin group was much faster;The recovery of nerve function was inhibited in inhibitor group.On the 7th day,compared with model group,the neurological score of baicalin group decreased(P<0.05).Compared with baicalin group,the neurological function score of inhibitor group was significantly higher(P<0.01).3.2 The reduction rate of grip strength:Compared with sham operation group,the reduction rate of grip strength decreased significantly after successful modeling;In model group,the reduction rate of grip strength gradually decreased,and the grip strength gradually recovered;In baicalin group,the recovery of the grip strength was more obvious;The recovery of the grip strength was inhibited in inhibitor group.On the 7th day,compared with model group,the reduction rate of grip strength decreased in baicalin group(P<0.05).Compared with baicalin group,the reduction rate of grip strength significantly increased in inhibitor group(P<0.05).3.3 The volume percentage of cerebral infarction in rats:There was no white infarct in the brain of sham operated rats.Rats in model group,baicalin group and inhibitor group had different degrees of cerebral infarction.Calculating the percentage of cerebral infarction volume in rats,it can be seen that,compared with model group,the volume percentage of cerebral infarction in baicalin group decreased(P<0.05).Compared with baicalin group,the volume percentage of cerebral infarction in inhibitor group increased(P<0.05).3.4 The brain morphology observation:The edges of gray and white matter of brain in sham operation group were clear,the distribution of cells in parietal cortex was normal,and the morphological of nerve cells was diverse.The edges of gray and white matter of brain tissue in the model group was unclear,cortical parietal neurons were lost,and neurons underwent ischemic changes(shrinkage,and deep dyeing),gliocyte proliferation,small vessel occlusion,accumulation of interstitial fluid.The degree of damage reduced in baicalin group,and neuronal loss was reduced.Brain tissue injury was not improved in inhibitor group.Conclusion1.Baicalin can increase the serum progesterone level in male rats with ischemic brain injury,and promote the expression of progesterone receptors in the brain tissue in normal male rats and rats with ischemic brain injury.2.Baicalin enhances the serum progesterone levels in male rats with ischemic brain damage,which may be related to the promotion of ACTH production,thereby promote the synthesis of P450scc and 3p-HSD in the renicapsule which is related to progesterone synthesis.3.The protective effect of baicalin on male rats with ischemic brain injury may be related to increasing the level of serum progesterone. |
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