Fig 2: Impact of shock or capsaicin treatment on cell signals associated with apoptosis. Rats exposed to variable intermittent shock (Shocked) a day after injury exhibited greater expression of tumor necrosis factor (TNF) (A), caspase-3 (C), and caspase-8 (E). Capsaicin treatment increased expression of TNF (B) and caspase-3 (D), but did not have a significant effect on caspase-8 (F). Representative blots from the 24 h time point are depicted to the right of the figures. Error bars indicate the SEM (n = 6). *p < 0.05.

Fig 3: Schematic representation of the possible mechanisms of PTEN involvement in neuropathic pain. (A) Peripheral nerve injury could downregulate the spinal astrocytic PTEN, which leads to the upregulation of phospho-mTOR and TNF-α and results in neuroinflammation and nociceptive sensitization. In addition, spinal microglia-astrocyte interactions also promote nociceptive responses. (B) Through the upregulation of spinal astrocytic PTEN by i.t. Ad-PTEN, peripheral nerve injury-induced upregulation of phospho-mTOR and TNF-α is inhibited, thereby inhibiting neuroinflammation and nociceptive sensitization. The effect of the upregulation of spinal PTEN by i.t. Ad-PTEN on attenuating peripheral nerve injury-induced microglial activation may be through suppressing the astrocyte-microglia interaction by reducing the astrocytic mediator TNF-α. Ad-PTEN, adenovirus-mediated phosphatase and tensin homolog deleted from chromosome 10; p-mTOR, phosphorylated mammalian target of rapamycin; TNF, tumor necrosis factor.

Fig 4: Impact of brilliant blue (BBG) and probenecid on shock-induced protein expression. Contused rats exhibited increased expression of TNF (A), caspase-3 (C), and caspase-8 (E) 3 h after they were exposed to shock. BBG attenuated shock-induced caspase-1 (B) and IL-1ß (D) expression, whereas probenecid generally increased expression. Shock treatment increased IL-18 (F) expression. Error bars indicate the SEM (n = 6). *p < 0.05.

Fig 5: Impact of shock on indices of hemorrhage and signals linked to inflammation and cell death. The experimental design is illustrated at the top of the figure. Eighteen hours after rats received a lower thoracic (T11–12 vertebrae) contusion injury, animals received a T2 spinal transection (Trans) or sham surgery. Six hours later, animals were exposed to noxious electrical stimulation (Shock) to the tail, or nothing (Unshock) and 3 h later a 1 cm portion of the spinal cord that encompassed the injury was collected. Additional tissue, 1-cm rostral and caudal to injury, was also obtained and prepared for cellular assays. Protein samples from non-transected animals that received shock (Sham-Shock) exhibited greater (A) absorbance at 420 nm, the absorption peak for hemoglobin. Western blotting showed that animals in the Sham-Shock group had higher levels of (B) alpha hemoglobin, (C) tumor necrosis factor (TNF), (D) caspase 1, (E) interleukin-1ß (IL-1ß), and (F) IL-18 at the site of injury. Nociceptive stimulation had no effect in animals that had received a spinal transection (Trans-Shock). (G) Representative blots from the injury center are depicted to the right of the figures. Error bars indicate the standard error of the mean (SEM). An asterisk above an error bar indicates that the effect of nociceptive stimulation was significant for that region of the spinal cord (p < 0.05, n = 6). An asterisk placed to the right indicates that stimulation had a broader effect that did not vary across the regions assayed.