Comparison of three techniques for decellularization of porcine bone-tendon-bone grafts.

Anterior cruciate ligament injuries are frequent afflictions related to sports or physical trauma. Autograft reconstruction strategies cause secondary injury to the patient. One alternative, supported by clinical evidence, is porcine xenografts. For clinical use, xenografts must be conditioned to avoid immune rejection. The most widely accepted procedure is tissue decellularization. We analyzed three decellularization strategies: the application of the anionic detergent sodium dodecyl sulfate (SDS), sonication, and freezing and thawing cycles. The treated tissues were evaluated histologically using H&E, Masson's trichrome, Verhoeff-van Gieson staining, and DAPI for fluorescent staining of nuclei. Finally, collagen fiber preservation was evaluated by quantifying this protein by colorimetry. The most efficient decellularization techniques were sonication and SDS. Collagen fibers were preserved in all experimental conditions.

Ketamine reduces intestinal injury and inflammatory cell infiltration after ischemia/reperfusion in rats.

PURPOSE: Intestinal ischemia reperfusion (I/R) induces severe injury and significant mortality. New therapeutic interventions are needed; ketamine is an anesthetic with anti-inflammatory properties, which has shown protective effects on I/R in various organs. This study investigated effects of ketamine on intestinal I/R injury. METHODS: Male Wistar rats underwent either sham surgery or 30 min of intestinal ischemia followed by 60 min reperfusion. Ketamine pretreatment was administered by intraperitoneal injections at doses of 100, 50, 12.5, or 6.25 mg/kg. The intestinal morphology, mucosal damage, leukocyte infiltration, serum P-selectin, serum intracellular adhesion molecule-1 (ICAM-1), serum antithrombin-III (ATIII), and myenteric ganglion cell structure were evaluated. RESULTS: Intestinal I/R led to severe mucosal damage, leukocyte (especially neutrophil) infiltration, P-selectin and ICAM-1 elevations, ATIII depletion, and myenteric ganglion cell morphological alterations. The ketamine dose dependently diminished these alterations (except for ICAM-1 serum levels), reaching statistical significance at 100, 50, and 12.5 mg/kg. CONCLUSIONS: Ketamine protects the intestine against I/R injury. Ketamine anesthesia has been recommended for clinical situations of sepsis and hemodynamic instability, both frequent during intestinal I/R. The clinical application of ketamine in situations of intestinal I/R warrants consideration.

Ketamine and the myenteric plexus in intestinal ischemia/reperfusion injury.

BACKGROUND AND AIMS: Intestinal ischemia/reperfusion (I/R) is a common clinical entity with severe consequences. We studied the effects of ketamine and the participation of the myenteric plexus in I/R injury. METHODS: Rats were divided into six groups: sham, IR (30 min ischemia/60 min reperfusion), KET+IR (50 mg/kg i.p. ketamine injection before I/R), DEN (myenteric plexus ablated with benzalkonium chloride (BAC) and sham operation performed), DEN+IR (BAC treated and I/R induced), and DEN+KET+IR (BAC treated, ketamine administered, and I/R induced). Serum concentrations of p-selectin, intracellular adhesion molecule-1 (ICAM-1), and antithrombin III (ATIII) were measured, and tissue samples were obtained for histological analysis. RESULTS: IR group had higher intestinal mucosa injury and elevated serum concentrations of ICAM-1 and p-selectin, as well as ATIII depletion, compared with sham group (P < 0.05). In KET+IR group these alterations were significantly reduced (P < 0.05). DEN group showed ICAM-1 elevations when compared with sham group (P < 0.05), and DEN+IR group showed no difference in any parameter compared with IR group. However, ketamine administration in group DEN+KET+IR had no effect on any parameter when compared with DEN+IR group. CONCLUSIONS: Ketamine was able to diminish alterations induced by I/R. Myenteric plexus ablation with BAC treatment alone had no effects on intestinal I/R injury. However, this procedure abolished ketamine's protective effects. Ketamine seems to require an intact enteric nervous system to exert its protective action.