Picroliv accelerates epithelialization and angiogenesis in rat wounds.

Tissue repair and wound healing are complex processes that involve inflammation, granulation and tissue remodeling. Angiogenesis plays a central role in wound healing. Earlier, we have shown that picroliv, a natural product obtained from the roots of Picrorhiza kurrooa, up-regulates the expression of vascular endothelial growth factor in human umbilical vein endothelial cells and of insulin-like growth factor in rats during hypoxia. In the present study, we have investigated the effect of picroliv in an ex vivo rat aorta ring model of angiogenesis. Picroliv enhanced the sprouting and migration of endothelial cells. We also investigated punch wound healing on days 4 and 7 after wounding by histology, morphometry and collagenization. The data showed improved re-epithelialization, neovascularization and migration of various cells such as endothelial, dermal myofibroblasts and fibroblasts into the wound bed after picroliv treatment. Immunohistochemical localization showed increased VEGF and alpha smooth muscle actin staining consistent with an increased number of microvessels in granulation tissue. These findings suggest that picroliv could be developed as a therapeutic angiogenic agent for the restoration of the blood supply in diseases involving inadequate blood supply such as limb ischemia, ischemic myocardium and wound healing.

Development of a rat pilocarpine model of seizure/status epilepticus that mimics chemical warfare nerve agent exposure.

We developed a rat pilocarpine seizure/status epilepticus (SE) model, which closely resembles 1.6-2.0 x LD50 soman exposure, to analyse the molecular mechanism of neuronal damage and to screen effective neuroprotectants against cholinergic agonist and chemical warfare nerve agent (CWNA) exposure. Rats implanted with radiotelemetry probes capable of recording electroencephalogram (EEG), electrocardiogram (ECG), temperature, and physical activity were treated with lithium chloride (5 mEq/kg, im), followed 24 h later by (ip) doses of pilocarpine hydrochloride. Based on radiotelemetry analysis, a dose of 240 mg/kg (ip) pilocarpine generated seizure/SE analogous to 1.6-2.0 x LD50 of soman. The model was refined by reducing the peripheral convulsions without affecting the central nervous system (CNS) by administering methylscopolamine bromide (1 mg/kg, ip), an anti-cholinergic that does not cross the blood-brain barrier. However, when methylscopolamine bromide was administered, a higher dose of pilocarpine (320 mg/kg, ip) was required to generate the equivalent seizure/SE. Histopathology data indicated that pilocarpine induces significant damage to the hippocampal region of the brain, with similar neuropathology to that of 1.6-2.0 x LD50 soman exposure. There was a reduction in body temperature after the administration of pilocarpine, as observed in organophosphate (OP) nerve agents exposure. The heart-rate of pilocarpine-treated animals increased compared to the normal range. The pilocarpine seizure/SE model was also reproducible in the absence of lithium chloride. These results support that pilocarpine seizure/SE model is useful in studying the molecular mechanisms of neuropathology and screening neuroprotectants following cholinergic agonist and CWNA exposure.