Exenatide exerts a neuroprotective effect against diabetic cognitive impairment in rats by inhibiting apoptosis: Role of the JNK/c­JUN signaling pathway.

Exenatide could reduce blood glucose and alleviate cognitive dysfunction induced by diabetes mellitus (DM). In the present study, a diabetic model was established in Sprague­Dawley rats to further explore the mechanism of exenatide on diabetes­induced cognitive impairment. Notably, the model rats performed poorly in the Morris water maze test and had more apoptotic neurons compared with the control rats. By contrast, exenatide attenuated cognitive impairment and inhibited neuronal apoptosis in the DM rat model. To explore the neuroprotective mechanisms of exenatide, western blotting was performed to detect the expression levels of markers of endoplasmic reticulum stress, including cytochrome c (Cyt­c), Caspase­3, JNK and c­JUN, in hippocampal tissue. Reverse transcription­quantitative PCR was also performed to measure the mRNA expression levels of Cyt­c and Caspase­3. After 16 weeks of treatment, exenatide treatment downregulated Cyt­c, Caspase­3, phosphorylated (p)­JNK and p­c­JUN expression in the hippocampal tissue of diabetic rats. Moreover, Cyt­c, Caspase­3, JNK and JUN expression levels were detected following treatment with a specific inhibitor of JNK (SP600125). The results revealed that SP600125 had similar inhibitory effects on the JNK pathway and ERS­related protein expression (Cyt­t, Caspase­3, p­JNK and p­c­JUN). These results suggested that exenatide improved cognitive dysfunction in DM rats and that the underlying mechanism may be associated with inhibiting apoptosis by suppressing the activation of JNK/c­JUN.

Morphological anatomy of thoracolumbar nerve roots and dorsal root ganglia.

The aim of this study is to ascertain the anatomic parameters of the spinal roots and dorsal root ganglia and to demonstrate their clinical significance. Samples from 24 adult autopsy subjects were obtained from roots and dorsal root ganglia at levels L1 through L5. The anatomic parameters of epidural nerve roots: the distance between the epidural nerve roots and the proximal edge of the dorsal root ganglia and the average diameter of the nerve root gradually, increased from L1 to L5. The midline nerve root angle gradually decreased from L1 to L5. The anatomic parameters of subarachnoid nerve roots: the length of subarachnoid nerve roots and both the ventral and dorsal roots' diameter, increased from L1 to L5. The number of ventral and dorsal rootlets per nerve root ranged from one to three. The anatomic parameters of dorsal root ganglia: the length and width of the thoracic and lumbar dorsal root ganglia, gradually increased from L1 to L5. The locations of the dorsal root ganglia were recorded as the intraspinal, intraforaminal and extraforaminal using some bony landmarks. Most dorsal root ganglia located intraforaminally, and the extraforaminal type is more common in the L5 root than other thoracic and lumbar roots, regardless of age. This knowledge is a must not only to avoid complications but also for the success, safety and effectiveness of microsurgical operations.

Preventive and therapeutic effect of simvastatin on secondary inflammatory damage of rats with cerebral hemorrhage.

OBJECTIVE: To investigate the preventive and therapeutic effect and mechanism of simvastatin on secondary inflammatory damage of rats with cerebral hemorrhage. METHODS: Sixty SD rat aged 9-12 weeks were chosen and divided into the control group, model group and simvastatin-treated group randomly with 20 rats in each group. Rats in the model group and simvastatin-treated group were infused with autologous fresh uncoagulated blood to the right brain tissue of the basal ganglia to build the cerebral hemorrhage model, while rats in the control group were treated with the same amount of normal saline. Then, rats in the simvastatin-treated group were given a gavage of 3 mg/kg of simvastatin once a day after modeling. Rats in the three groups were given nerve dysfunction score (NDS) and wet-dry weighting method was used to detect the brain water content (BWC) of brain tissues around the lesion of the rats. Then Nissl staining was conducted and the undamaged neurons were counted. Immunohistochemical SP method was applied to count the number of NF-κB, TLR4 and IL-1ß positive cells in brain tissues around the lesions, and the immuno fluorescence method was employed to determine the expression levels of NF-κB, TLR4 and IL-1ß proteins. RESULTS: The NDS results of the simvastatin-treated group at all time points were all significantly higher than those of the model group (P < 0.05); the BWC values of the simvastatin-treated group at all time points were all significantly lower than those of the model group at the same periods (P < 0.05); the number of the undamaged neurons around the lesions of the simvastatin-treated group at all time points were all significantly higher than those of the model group (P < 0.05); seven days after treatment, the number of the NF-κB, TLR4 and IL-1ß positive cells in brain tissues around the lesions of the simvastatin-treated group were all significantly lower than those of the model group (P < 0.05), and its expression levels of NF-κB, TLR4 and IL-1ß protein were also significantly lower than those of the model group (P < 0.05). CONCLUSIONS: Simvastatin can inhibit the expressions of NF-κB, TLR4 and IL-1ß proteins in rats with cerebral hemorrhage, and protect neurons and reduce secondary inflammatory damages by down-regulating the above protein-mediated inflammatory responses.

Tanshinone IIA prevents the loss of nigrostriatal dopaminergic neurons by inhibiting NADPH oxidase and iNOS in the MPTP model of Parkinson's disease.

Tanshinone IIA is one of the major constituents of Salvia miltiorrhiza Bunge known as Danshen. Recent reports have shown that Tanshinone IIA has neuroprotective effects against cerebral ischemia/reperfusion injury and traumatic injury of the spinal cord in rats. However, whether Tanshinone IIA has any neuroprotective effect in Parkinson's disease remains unknown. In this study, we evaluated whether Tanshinone IIA promotes the survival of nigrostriatal dopaminergic (DA) neurons in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease. MPTP induced degeneration of nigrostriatal DA neurons and microglial activation as visualized by tyrosine hydroxylase and CD11b immunoreactivity. The results of Western blot and immunohistochemistry showed upregulation of NADPH oxidase and iNOS in the MPTP-treated substantia nigra pars compacta. Treatment with Tanshinone IIA prevented degeneration of nigrostriatal DA neurons and increased the level of striatal dopamine content. This neuroprotection afforded by Tanshinone IIA was associated with the suppression of microglial activation and reduced expression of NADPH oxidase and iNOS. The present findings show that Tanshinone IIA may possess anti-inflammatory and anti-oxidative properties and may have therapeutic value in the treatment of Parkinson's disease.

Progesterone protects blood-brain barrier function and improves neurological outcome following traumatic brain injury in rats.

Inflammatory responses are associated with blood-brain barrier (BBB) dysfunction and neurological deficits following traumatic brain injury (TBI). The aim of the present study was to investigate the effects of progesterone on the expression of the inflammatory mediators prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), nuclear factor κB (NF-κB) and tumor necrosis factor-α (TNF-α) in the brain, BBB permeability, cerebral edema and neurological outcome, as well as to explore the mechanism of its neuroprotective effect. In this study, male rats were randomly divided into three groups: a sham-operated group (SHAM), a TBI group (TBI) and a progesterone treatment group (TBI-PROG). The TBI model was established using a modified Feeney's weight-dropping method. Brain samples were extracted 24 h following injury. The expression levels of COX-2 and NF-κB were examined using immunohistochemistry, whilst the expression levels of PGE2 and TNF-α were detected by enzyme-linked immunosorbent assay. BBB permeability was analyzed using Evans blue and cerebral edema was determined using the dry-wet method. The neurological outcome was evaluated using the modified neurological severity score test. The results revealed that progesterone treatment significantly reduced post-injury inflammatory response, brain edema and Evans blue dye extravasation, and improved neurological scores compared with those in the TBI group. In conclusion, the inhibition of inflammation may be an important mechanism by which progesterone protects the BBB and improves neurological outcome.

Improved cognitive outcome after progesterone administration is associated with protecting hippocampal neurons from secondary damage studied in vitro and in vivo.

Previous studies reported that progesterone could improve cognitive outcome following TBI. Moreover, some evidence implied that the hippocampus is associated with cognitive function. The aim of this study was to investigate the neuroprotective effects of progesterone on hippocampal neurons in vitro and in vivo, and its influence on the cognitive outcome. In vitro, the model of primary cultured hippocampal neurons against glutamate-induced excitotoxic damage was used. After 10-day culture, neurons were pretreated with progesterone in a concentration 10 ng/ml, 48 h before a 5-min exposure to 200 µmol/l glutamate. Then 24h after glutamate exposure, the nerve cells were observed and LDH was detected. The results showed progesterone protected the cultured hippocampal neurons morphology and significantly reduced the amount of LDH. In vivo, the model of TBI was established by modified Feeney's weight-dropping method. The progesterone was given in a dose of 16 mg/kg by intraperitoneal injection 1h post injury and subsequent injections subcutaneously at 6h and 12h after TBI. Brain samples were extracted at 24h after injury. Histology and the iNOS expression were examined by Nissl stain, immunohistochemistry and Western blot. The cognitive outcome was assessed by Morris water maze test (MWM). The results revealed that the neuronal cell damage and the expression of iNOS in the hippocampus CA1 were significantly decreased after progesterone administration. Progesterone significantly improved cognitive outcome after TBI. The results suggest that the positive effects of progesterone on cognitive outcome may be linked to protecting hippocampal neurons from secondary damage.

Progesterone inhibits the expression of cycloxygenase-2 and interleukin-1ß in neonatal rats with hypoxic ischemic brain damage.

Recent studies found that progesterone (PROG) has a noticeable preventive effect on brain injuries. However, the underlying mechanisms of these effects, particularly on hypoxic ischemic brain damage (HIBD), remain unclear. This study observed the influence of PROG on the expression of cycloxygenase-2 (COX-2) and interleukin-1ß (IL-1ß) in HIBD neonatal rats, and explored the corresponding molecular mechanisms underlying the neuroprotective effect of PROG. Sixty 7-day-old neonatal Wistar rats were divided into sham operation (control), hypoxic ischemia (HI), and drug prophylaxis (PROG) groups, and HIBD animal models were routinely established. The PROG group was intraperitoneally injected with 0.5 g/L PROG at a dosage of 8 mg/kg 30 min before establishment of the model. All the animals were sacrificed 24 h after modeling. Changes in the COX-2 and IL-1ß contents in the brain tissues were determined using enzyme-linked immunosorbent assay. Protein expression was observed using immunohistochemistry, and mRNA expression was determined using reverse transcription polymerase chain reaction. The expression and contents of COX-2 and IL-1ß in the HI group were significantly higher than those in the control group (P < 0.01). Compared with the HI group, the PROG group showed noticeably lower expression and contents of COX-2 and IL-1ß (P < 0.05). In conclusion, PROG can inhibit the expression of COX-2 and IL-1ß in brain tissue, further reducing the level of COX-2 and IL-1ß, which may be one of the mechanisms for protection from HIBD.

Morphological and molecular identification of two strains of dermatophytes.

In this study, we used traditional morphological and molecular identification methods to preliminarily identify two strains of dermatophytes. The two strains were observed under the microscope. And then the dermatophytes were cultured on Sabouraud's dextrose agar (SDA). The 18S rRNA regions of the two dermatophyte strains were amplified by polymerase chain reaction (PCR), and the PCR products were sequenced and compared with GenBank data. BLAST tools and DNAMAN software were used to analyze the sequences. To further determine highly homologous sequences, a phylogenetic tree was constructed using the Neighbor-Joining method. The two strains of dermatophytes were identified by traditional morphological identification as Epidermophyton floccosum and Microsporum ferrugineum. The 18S rRNA sequence analyses showed high similarities to Cladosporium cladosporioides isolate C115LM-UFPR and Ascomycete sp. LB68A1A2. Epidermophyton and Cladosporium belong to dermatophyte, while Microsporum ferrugineum and Ascomycete belong to microsporum. The two novel strains of dermatophytes were therefore identified as Cladosporium cladosporioides isolate C115LM-UFPR (JN650537, Cladosporium) and Ascomycete sp. LB68A1A2 (AY770409, Ascomycete sp).

Progesterone treatment improves cognitive outcome following experimental traumatic brain injury in rats.

Progesterone (PROG) has recently been shown to have a neuroprotective effect and improve cognitive outcome in animal models of traumatic brain injury (TBI). However, the precise mechanisms remain unclear. This study was aimed to investigate the inhibitory effects of PROG on inflammation and apoptosis in the hippocampus after TBI and its influence on the cognitive outcome. In this study, the model of TBI was established by modified Feeney's weight-dropping method. The PROG was given in a dose of 16 mg/kg by intraperitoneal injection 1h post injury and subsequent injections subcutaneously at 6h and 12 h after TBI. Brain samples were extracted at 24 h after trauma. The expression of COX-2 and caspase-3 was measured by immunohistochemistry and western blot technique. The cognitive outcome was assessed by Morris water maze test (MWM). The results revealed that the expression of COX-2 and caspase-3 in TBI-PROG group was distinctly less than those of the TBI group (p < 0.05). In addition, the performance of Morris water maze showed that progesterone treatment exhibited shorter latencies, more platform crossings and more time swimming in the quadrant area in the TBI+PROG rats compared to the TBI rats. In conclusion, post-TBI PROG administration may attenuate inflammation and apoptosis in the hippocampus, and this may be one of the mechanisms by which PROG improves cognitive outcome following TBI.