Estrogen Receptor α Agonist is Beneficial for Young Female Rats Against Chronic Unpredicted Mild Stress-Induced Depressive Behavior and Cognitive Deficits

BACKGROUND

Women are reported more likely to develop depression and dementia. However, the involved mechanism is poorly understood.

OBJECTIVE

Here, we clarified the role of estrogen receptor α (ERα) in depression and cognitive deficit in young female rats.

METHODS

After being exposed to 7-weeks' chronic unpredicted mild stress (CUMS), the depression resilient rats (Res rats) and depressed rats (Dep rats) were selected according to their records in sucrose preference test, forced swimming test, and open field test. Their cognition abilities were tested by Morris water maze. Proteomic assay, immunoprecipitation, western blotting, immunohistochemical, and Nissl staining were also used to understand the involved mechanism.

RESULTS

Compared with control rats and Res rats, Dep rats showed cognitive deficits and hippocampal impairments revealed by proteomic data, neuron losses, increased cleaved caspase-3, β-catenin phosphorylation, and glycogen synthase kinase3β (GSK3β) activation. As ERα, but not ERβ, was found declined in hippocampi of Dep rats, 4,4k,4a-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol (PPT, an ERα agonist, 1 mg/kg/day), was used to treat Dep rats (Dep + PPT). Twenty days later, the depressive behaviors, cognition deficits, and hippocampal neuron loss were rescued in Dep + PPT rats. Furthermore, Res and Dep + PPT rats had higher levels of β-catenin combined with ERα and lower levels of β-catenin combined with GSK3β than Dep rats in hippocampi.

CONCLUSION

These results demonstrated hippocampal ERα is an important pro-resilient factor in CUMS-induced depressive behaviors and cognitive deficits. It was also given that the neuroprotection afforded by hippocampal ERα/Wnt interactions have significant implications for cognition and emotion in young females.

Protection of melatonin against acidosis-induced neuronal injuries

Acidosis, a common feature of cerebral ischaemia and hypoxia, plays a key role in these pathological processes by aggravating the ischaemic and hypoxic injuries. To explore the mechanisms, in this research, we cultured primary neurons in an acidic environment (potential of hydrogen [pH]6.2, 24 hours) to mimic the acidosis. By proteomic analysis, 69 differentially expressed proteins in the acidic neurons were found, mainly related to stress and cell death, synaptic plasticity and gene transcription. And, the acidotic neurons developed obvious alterations including increased neuronal death, reduced dendritic length and complexity, reduced synaptic proteins, tau hyperphosphorylation, endoplasmic reticulum (ER) stress activation, abnormal lysosome‐related signals, imbalanced oxidative stress/anti‐oxidative stress and decreased Golgi matrix proteins. Then, melatonin (1 × 10⁻⁴ mol/L) was used to pre‐treat the cultured primary neurons before acidic treatment (pH6.2). The results showed that melatonin partially reversed the acidosis‐induced neuronal death, abnormal dendritic complexity, reductions of synaptic proteins, tau hyperphosphorylation and imbalance of kinase/phosphatase. In addition, acidosis related the activations of glycogen synthase kinase‐3β and nuclear factor‐κB signals, ER stress and Golgi stress, and the abnormal autophagy‐lysosome signals were completely reversed by melatonin. These data indicate that melatonin is beneficial for neurons against acidosis‐induced injuries.

[Efficiency analysis on functional protection of nerve plane-oriented laparoscopic total mesorectal excision]

Objective: Using previous total mesorectal excision with pelvic autonomic nerve preservation (PANP+TME) and simple total mesorectal excision (TME) without emphasis on retained nerves as control, we explore the advantages of nerve plane-oriented laparoscopic total mesorectal excision (NPO+LTME) on urinary and sexual function. Methods: A retrospective cohort study was carried out. Case inclusion criteria: (1) male patients with pathologically confirmed middle and low rectal adenocarcinoma (4 to 11 cm from the anus); (2) stage T1-2tumor; (3) normal sexual life before operation. Exclusion criteria: (1) no pathological diagnosis before surgery; (2) local recurrence or distant metastasis; (3) preoperative neoadjuvant chemoradiotherapy; (4) opensurgery and laparoscopic surgery conversionto open; (5) no follow-up data. According to the above criteria, clinical data of 173 male patients with low and middle rectal adenocarcinoma who underwent radical operation for laparoscopic rectal cancer from July 2003 to July 2018 at the Department of Gastrointestinal Surgery, Wuhan University People's Hospital were collected. According to different surgical methods, patients were divided into TME group (58 cases), PANP+TME group (63 cases) and NPO+LTME group (52 cases). There were no significant differences in the baseline data including age, body mass index and pathological examination between the 3 groups (all P>0.05). The nerve plane referred to the nerve, the adipose tissue, the extremely finecapillaries around the nerve with overlying fine membranous tissue. NPO+LTME referred to the process of laparoscopic TME guided by the nerve plane, performing in the loose connective tissue between the nerve plane and the rectal properfascia, in order to ensure the integrity of the nerve plane, and maximally protect the patient's urinary and reproductive functions. The operation time, intraoperative blood loss, urinary catheter removal time, urinary function grading, postoperative first erection time, and erectile function and ejaculation function were observed and compared among the 3 groups at 3- and 6-month after operation. Results: In the NPO+LTME group, the PANP+TME group and the TME group, the operation time was (181.9±24.5) minutes, (176.7±29.2) minutes and (137.7±16.2) minutes, respectively (F=54.868, P<0.001); the intraoperative blood lost was (6.0±1.4) ml, (6.5±1.8) ml and (12.8±4.6) ml, respectively (F=95.016, P<0.001); the time to postoperative removal of the catheter was (2.4±1.1) days, (3.7 ±1.7) days and (6.5±2.4) days, respectively (F=79.409, P<0.001); the first postoperative erection time was (1.6±0.6) days, (8.9±2.7) days and (15.9±6.8) days (F=177.677, P<0.001), respectively, whose differences were all statistically significant (all P<0.01). In comparison of urinary function grading, the proportion of grade I (normal function, no urinary dysfunction) in the NPO+LTME, the ANP+TME group and the TME group was 84.1% (53/63), 39.7% (23/58) and 19.2% (10/52), respectively, and the difference was statistically significant (H=52.915, P<0.001). At postoperative 3- and 6-month, proportion of patients with grade I erectile function (normal erectile function) was 77.8% (49/63) and 85.7% (54/63), 44.8% (26/58) and 53.4% (31/58), 28.8% (15/52) and 48.1% (25/52) in the NPO+LTME group, the PANP+TME group, and the TME group, respectively. The differences were statistically significant (H=91.709, P<0.001; H=79.692, P<0.001). The proportion of patients with grade I ejaculation function (with ejaculation, no abnormalities in routine semen examination before and after surgery) at 3- and 6-month after surgery in the NPO+LTME group, the PANP+TME group and the TME group was 82.5% (52/63) and 87.3% (55/63), 53.4% (31/58) and 60.3% (35/58), 28.8% (15/52) and 46.1% (24/52), respectively. The differences were statistically significant as well (H=86.543, P<0.001; H=78.667, P<0.001). Patients in the NPO+LTME group had no grade III erections and ejaculation disorders. Conclusion: The surgical procedure of NPO+LTME can promote the recovery of postoperative neurological function and preserve urination and sexual function better.

In Vivo Biocompatibility and Improved Compression Strength of Reinforced Keratin/Hydroxyapatite Scaffold

A rapid freezing/lyophilizing/reinforcing process is suggested to fabricate reinforced keratin/hydroxyapatite (HA) scaffold with improved mechanical property and biocompatibility for tissue engineering. The keratin, extracted from human hair, and HA mixture were rapidly frozen with liquid nitrogen and then lyophilized to prepare keratin/HA laminar scaffold. The scaffold was then immersed in PBS for reinforcement treatment, and followed by a second lyophilization to prepare the reinforced keratin/HA scaffold. The morphology, mechanical, chemical, crystal and thermal property of the keratin/HA scaffold were investigated by SEM, FTIR, XRD, DSC, respectively. The results showed that the keratin/HA scaffold had a high porosity of 76.17 ± 3%. The maximum compressive strength and compressive modulus of the reinforced scaffold is 0.778 and 3.3 MPa respectively. Subcutaneous implantation studies in mice showed that in vivo the scaffold was biocompatible since the foreign body reaction seen around the implanted scaffold samples was moderate and became minimal upon increasing implantation time. These results demonstrate that the keratin/HA reinforced scaffold prepared here is promising for biomedical utilization.

Fluorocitrate induced the alterations of memory-related proteins and tau hyperphosphorylation in SD rats

Astrocytes provide structural, metabolic and trophic supports for neurons. However, there are no direct evidences whether astrocytes involve in the regulation of synaptic proteins expression and tau phosphorylation until now. Here, we injected 1 nmol fluorocitrate (FC), which preferentially taken up by astrocytes and results in reversible inhibition of the astrocytic tricarboxylic acid cycle, into the left lateral ventricle of the brain in the SD rats for 1h, and found that FC treatment decreased several memory-related proteins levels, such as AMPA receptor GluR1/2, postsynaptic density protein 93/95, Arc and phosphorylated cAMP response element binding proteins, while increased synaptophysin and synapsin I levels in the hippocampus. FC treatment also increased the levels of phosphorylated tau at multiple Alzheimer-related phosphorylation sites, as well as activation of glycogen synthase kinase-3β and inactivation of protein phosphatase-2A. Similar effects were also observed in the primary hippocampal neurons, which were cultured with the conditioned media from FC-treatment primary astrocytes. Our data suggest that astrocytes regulate neuronal tau phosphorylation and several synaptic proteins expression.

Upregulation of astrocytes protein phosphatase-2A stimulates astrocytes migration via inhibiting p38 MAPK in tg2576 mice

One of the earliest neuropathological changes in Alzheimer disease (AD) is the accumulation of astrocytes at sites of β-amyloid (Aβ) deposits, but the cause of this cellular response is unclear. As the activity of protein phosphatase 2A (PP2A) is significantly decreased in the AD brains, we studied the role of PP2A in astrocytes migration. We observed unexpectedly that PP2A activity associated with glial fibrillary acidic protein, an astrocyte marker, was significantly upregulated in tg2576 mice, demonstrated by an increased enzyme activity, a decreased demethylation at leucine-309 (DM-PP2Ac), and a decreased phosphorylation at tyrosine-307 of PP2A (pY307-PP2Ac). Further studies by using in vitro wound-healing model and transwell assay demonstrated that upregulation of PP2A pharmacologically and genetically could stimulate astrocytes migration. Activation of PP2A promotes actin organization and inhibits p38 mitogen-activated protein kinases (p38 MAPK), while simultaneous activation of p38 MAPK partially abolishes the PP2A-induced astrocytes migration. Our data suggest that activation of astrocytes PP2A in tg2567 mice may stimulate the migration of astrocytes to the amyloid plaques by p38 MAPK inhibition, implying that PP2A deficits observed in AD may cause Aβ accumulation via hindering the astrocytes migration.

Essential role of tau phosphorylation in adult hippocampal neurogenesis

An increased hippocampal neurogenesis has been observed in Alzheimer disease (AD), the most common neurodegenerative disorder characterized with accumulation of β-amyloid (Aβ) and hyperphosphorylated tau (p-tau). Studies in transgenic mouse models suggest that the amyloidosis suppresses adult neurogenesis. Although emerging evidence links tau to neurodevelopment, the direct data regarding tau phosphorylation in adult neurogenesis is missing. Here, we found that the immature neurons, identified by doublecortin (DCX) and neurogenic differentiation factor (neuroD), were only immunoreactive to p-tau but not to the non-p-tau in adult rat brain and human patients with AD, and the p-tau was coexpressed temporally and spatially with DCX and neuroD in the hippocampal dentate gyrus (DG) of the rat brains during postnatal development. A correlative increase of immature neuron markers and tau phosphorylation was induced in rat hippocampal DG by upregulating glycogen synthase kinase-3 (GSK-3), a crucial tau kinase, and the increased neurogenesis was due to an enhanced proliferation but not survival or differentiation of the newborn neurons. The hippocampal neurogenesis was severely impaired in tau knockout mice and activation of GSK-3 in these mice did not rescue the deficits. These results reveal an essential role of tau phosphorylation in adult hippocampal neurogenesis. It suggests that spatial/temporal manipulation of tau phosphorylation may be compensatory for the neuron loss in neurological disorders, including AD.

Effects of complete Freund's adjuvant on immunohistochemical distribution of IL-1beta and IL-1R I in neurons and glia cells of dorsal root ganglion

AIM

To investigate the effects of complete Freund adjuvant (CFA) on inflammatory hyperalgesia and morphological change of the coexistence of interleukin-1 beta (IL-1beta) and type I IL-1 receptor (IL-1RI) in neurons and glia cells of rat dorsal root ganglion (DRG).

METHODS

The pain-related parameters and the expression of IL-1RI and IL-1beta positive neurons and glia cells of DRG in normal saline (NS) and adjuvant-induced arthritic (AA) group were examined with pain behavior assessment methods and immunohistochemical assay, respectively.

RESULTS

Five hours, 1 d, and 2 d after intra-articular injection of 50 microL CFA, tactile hyperalgesia induced by CFA was observed in the foot flexion and extension scores of the ipsilateral hindpaw of AA group. Three days after injection, the distribution of IL-1RI/IL-1beta double-stained coexisted neurons and glia cells were observed in ipsilateral DRG of both groups. The number of IL-1beta positive neurons, IL-1RI positive neurons, IL-1beta/IL-1RI double-stained neurons, and IL-1RI positive glia cells in ipsilateral DRG of the AA group were higher than that of NS group (P<0.05 or P<0.01).

CONCLUSION

The coexistence of IL-1beta and IL-1RI in neurons and nonneuronal cells suggests an as yet unknown autocrine and/or paracrine function of IL-1beta in the DRG. The function was enhanced in articular arthritis induced by CFA and could play an important role in hyperalgesia under inflammatory conditions.

Melatonin attenuates isoproterenol-induced protein kinase A overactivation and tau hyperphosphorylation in rat brain

Hyperphosphorylation of microtubule-associated protein tau at specific sites is a recognized pathological process in Alzheimer's disease (AD), and protein kinase A (PKA) is a crucial kinase in AD-like tau hyperphosphorylation. In the present study, isoproterenol (ISO) was injected bilaterally into hippocampus of rat brain; ISO is a specific PKA activator and it induces tau hyperphosphorylation. With this system, melatonin (MT) was shown to protect against ISO-induced tau hyperphosphorylation. We found that hippocampal injection of ISO (0.02 microm) induced PKA overactivation and tau hyperphosphorylation at both paired helical filament (PHF)-1 and tau-1 sites. ISO injection also resulted in activation of superoxide dismutase (SOD) and elevation of malondialdehyde (MDA), parameters suggesting elevated oxidative stress. Preinfusion of MT intraperitoneally partially reversed ISO-induced tau hyperphosphorylation at the PHF-1 epitope (1 and 10 mg/kg continuously for 4 wk or 10 mg/kg for 1, 2 or 3 wk) and tau-1 epitope (10 mg/kg for 2 wk). Furthermore, MT (10 mg/kg for 2 wk) obviously antagonized ISO-induced PKA overactivation, as well as enhanced SOD activity and decreased the level of MDA. It is suggested from these data that ISO may induce abnormal hyperphosphorylation of tau through not only the activation of PKA but also because of the fact that it increases oxidative stress; MT may protect against ISO-induced tau hyperphosphorylation through suppression of both PKA overactivation and oxidative stress.

[Treatment of trigeminal neuralgia with radiofrequency thermocoagulation: report of 890 cases]

OBJECTIVE

To study the modified method of radiofrequency thermocoagulation for treatment of trigeminal neuralgia.

METHODS

The sensory root of semilunar ganglion of trigeminal nerve in the foramen ovale was punctured by needle, which connected with electrode of radiofrequency thermocoagulation instrument. First, the right position was located by rectangle wave stimulation; second, the temperature was up to 88 degrees centigrade quickly, 2 to 3 sections of the sensory root were coagulated but it is not necessary to overstress the preservation of the tactile sensation of the face.

RESULTS

Of 890 patients, the efficacy rate was 98.2%, the ineffective rate was 0.49%, the recurrence rate was 10.67% with a follow-up period of 1-10 years. Pains can be controlled by radiofrequency thermocoagulation for patients with recurrence.

CONCLUSION

Radiofrequency thermocoagulation was a safe, simple and effective method. It is important that precise location and strict manipulation could avoid severe complications. Quick heating could relieve patients' pain and thermocoagulation of multi sections could decrease recurrence.