Short-term pre- and post-operative stress prolongs incision-induced pain hypersensitivity without changing basal pain perception.

BACKGROUND: Chronic stress has been reported to increase basal pain sensitivity and/or exacerbate existing persistent pain. However, most surgical patients have normal physiological and psychological health status such as normal pain perception before surgery although they do experience short-term stress during pre- and post-operative periods. Whether or not this short-term stress affects persistent postsurgical pain is unclear. RESULTS: In this study, we showed that pre- or post-surgical exposure to immobilization 6 h daily for three consecutive days did not change basal responses to mechanical, thermal, or cold stimuli or peak levels of incision-induced hypersensitivity to these stimuli; however, immobilization did prolong the duration of incision-induced hypersensitivity in both male and female rats. These phenomena were also observed in post-surgical exposure to forced swimming 25 min daily for 3 consecutive days. Short-term stress induced by immobilization was demonstrated by an elevation in the level of serum corticosterone, an increase in swim immobility, and a decrease in sucrose consumption. Blocking this short-term stress via intrathecal administration of a selective glucocorticoid receptor antagonist, RU38486, or bilateral adrenalectomy significantly attenuated the prolongation of incision-induced hypersensitivity to mechanical, thermal, and cold stimuli. CONCLUSION: Our results indicate that short-term stress during the pre- or post-operative period delays postoperative pain recovery although it does not affect basal pain perception. Prevention of short-term stress may facilitate patients' recovery from postoperative pain.

[Alternation of proteins in brain of Parkinson's disease model rats after the transplantation of TH-NTN gene modified bone marrow mesenchymal stem cells].

OBJECTIVE: To explore the effects of tyrosine hydroxylase-neurturin (TH-NTN) gene modified bone marrow mesenchymal stem cell (BMSC) transplantation in Parkinson's disease (PD) model rats and the alternations of correlated proteins. METHODS: The PD rat model was established by the 2-point injection of 6-hydroxydopamine (6-OHDA) into unilateral (right) striatum. Successful modeling rats were separated into PD, BMSC and TH-NTN-BMSC groups. BMSC and TH-NTN-BMSC groups were transplanted into BMSCs and TH-NTN gene modified BMSC cells separately into right striatum. After transplantation, ethology detection in all groups was made with an intraperitoneal injection of apomorphine (APO). Dopamine (DA) and Dihydroxyphenylacetic Acid (DOPAC) in striatum were detected by high performance liquid electrochemical analysis. TH and NTN proteins in right striatum were also analyzed by immunohistochemistry and Western blot. Finally the density of dopamine receptors in post synaptic density of dopaminergic synapses of corpus striatum were compared between each group by post-embedding immunogold electron microscopy. RESULTS: After an injection of APO, rotation frequency decreased in TH-NTN-BMSC group, i.e. (5.7 ± 1.3) circles/min versus (10.8 ± 2.2), (9.9 ± 1.2) circles/min in PD and BMSC groups (P < 0.05). For proteins in right striatum, DA, (0.421 ± 0.113) and DOPAC, (0.093 ± 0.012) nmol/L increased significantly versus (0.208 ± 0.043), (0.043 ± 0.017) nmol/L in PD and (0.231 ± 0.082), (0.044 ± 0.023)noml/L in BMSC groups (P < 0.05). Also a lower density of D2 receptors at (623 ± 96)/µm(2) in TH-NTN-BMSC group versus (923 ± 132)/µm(2) in PD and (860 ± 116)/µm(2) in BMSC groups was also found. CONCLUSION: The combined therapy of TH and NTN genes increases the synthesis of DA and also protects the dopaminergic neurons to achieve double therapeutic effects. It may provide potential innovations of PD genetic therapy.

[Alcohol-induced proliferation of neurons in mouse hippocampal dentate gyrus: a possible role of ceramide].

To investigate the role and mechanism of ceramide (Cer) regulation in alcohol-induced neuronal proliferation and the newborn neurons formation, we used sphingomyelin synthase 2 (predominant enzyme of Cer metabolism) knockout (SMS2(-/-)) and wild type (WT) female mice to establish the model of prenatal alcohol exposure. In 24 h after being given birth (postnatal day 0, P0), the offspring of model mice received blood sphingomyelin (SM) measurement with enzymatic method. On P0, P7, P14 and P30, the proliferation of granule cells in the dentate gyrus and newborn neurons were investigated with immunofluorescent labeling. The expression of protein kinase Cα (PKCα) in the hippocampus was tested with Western blot analysis. The results showed that the SM level of blood in SMS2(-/-) pups was significantly lower than that in WT pups. No matter in SMS2(-/-) or WT mice, the prenatal alcohol exposure down-regulated the SM levels in pups with dose-dependency. In both SMS2(-/-) and WT pups, the number of proliferative neurons and newborn neurons in the dentate gyrus gradually decreased with the growing age. Compared with the WT pups, SMS2(-/-) pups showed significantly more proliferative neurons and newborn neurons in the dentate gyrus. Notably, prenatal alcohol exposure dose-dependently increased proliferative neurons and newborn neurons in the dentate gyrus in both WT and SMS2(-/-) pups. The hippocampal expression of PKCα protein in SMS2(-/-) mice was lower than that in WT mice, and prenatal alcohol exposure could up-regulate the PKCα protein expression in both WT and SMS2(-/-) mice with dose dependency. These results suggest that alcohol exposure during pregnancy can induce the compensatory neural cell proliferation and the production of newborn neurons in offspring, and the Cer-ceramide-1-phosphate (C1P) pathway is involved in alcohol-induced neural cell proliferation. The activation of PKCα may be a key step to start the Cer-C1P pathway and up-regulate the alcohol-induced neural cell proliferation and the newborn neurons formation.

[Identification of a novel mutation IVS2-2A-->C of SEDL gene in a Chinese family with X-linked spondyloepiphyseal dysplasia tarda].

OBJECTIVE: To identify the mutation of spondyloepiphyseal dysplasia tarda (SEDL) gene in a large Chinese family with X-linked spondyloepiphyseal dysplasia tarda and to make a discussion on the pathogenesis of SEDL at the molecular level. METHODS: In two patients, four exons comprising the SEDL open reading frame as well as their exon/intron boundaries were analyzed by bi-directional direct sequencing of PCR products. The sequencing results were compared against the normal sequences in GenBank to find the mutation. Then the mutation was identified in other members of the family. RESULTS: A nucleotide substitution of the splice acceptor in SEDL intron 2, IVS2 -2A-->C,was detected in two affected individuals (IV(15) V(3)) in the Chinese family with SEDL, but no sequence change occurring on exons 3-6 was detected. The transversion was also identified in four heterozygous carriers. The mutation was not found in two unaffected male individuals and fifteen normal controls. Furthermore, four potential carriers were identified in the family. CONCLUSION: The mutation IVS2 -2A-->C of SEDL gene was firstly determined in the world. The change of the splice acceptor in SEDL intron 2 may cause skipping of exon 3 which is responsible for the disease. Molecular diagnosis can be made by detecting the mutation.