Crotalus helleri venom preconditioning reduces postoperative cerebral edema and improves neurological outcomes after surgical brain injury

Abstract

Introduction Postoperative cerebral edema is a devastating complication in neurosurgical patients. Loss of blood-brain barrier integrity has been shown to lead to the development of brain edema following neurosurgical procedures. The aim of this study was to evaluate preconditioning with Crotalus helleri venom (Cv-PC) as a potential preventive therapy for reducing postoperative brain edema in the rodent SBI model. C. helleri venom is known to contain phospholipase A2 (PLA2), an enzyme upstream to cyclooxygenase-2 (COX-2) in the inflammatory cascade, acts to increase the production of inflammatory mediators, such as prostaglandins. We hypothesize that Cv-PC will downregulate the response of the COX-2 pathway to injury, thereby reducing the inflammatory response and the development of brain edema after SBI. Materials and Methods 75 male Sprague Dawley rats (280–330g) were divided to the following groups—naïve+vehicle, naïve+Cv-PC, sham, vehicle, Cv-PC, Cv-PC+NS398 (COX-2 inhibitor). Vehicle preconditioned and Cv-PC animals received either three daily subcutaneous doses of saline or C. helleri venom at 72 h, 48 h, and 24 h prior to surgery. In Cv-PC+NS398 animals, NS398 was administered intraperitoneally one hour prior to each Cv-PC injection. Sham-operated animals received craniotomy only, whereas SBI animals received a partial right frontal lobectomy. Neurological testing and brain water content were assessed at 24 h and 72 h after SBI; COX-2 and PGE2 expression was assessed at 24 h postoperatively by Western blot and immunohistochemistry, respectively. Results At 24 h after SBI, the vehicle-treated animals were observed to have increased brain water content (83.1 ± 0.2%) compared to that of sham animals (80.2 ± 0.1%). The brain water content of vehicle-treated animals at 72 h post-SBI was elevated at 83.3 ± 0.2%. Cv-PC-treated animals with doses of 10% LD50 had significantly reduced brain water content of 81.92 ± 0.7% and 81.82 ± 0.3% at 24 h and 72 h, respectively, after SBI compared to that of vehicle-treated animals, while Cv-PC with 5% LD50 doses showed brain water content that trended lower but did not reach statistical significance. At 24 h and 72 h post-SBI, Cv-PC-treated animals had significantly higher neurological score than vehicle-treated animals. The COX-2 over-expression characterized in SBI was attenuated in Cv-PC-treated animals; NS398 reversed the protective effect of Cv-PC on COX-2 expression. Cv-PC tempered the over-expression of the inflammatory marker PGE2. Conclusion Our findings indicate that Cv-PC may provide a promising therapy for reducing postoperative edema and improving neurological function after neurosurgical procedures.

Biological effects of selective COX-2 inhibitor NS398 on human glioblastoma cell lines

“…For comparative analysis of groups of data, two-way ANOVA followed by Bonferroni post hoc test was used (*p < 0.05, **p < 0.01, ****p < 0.0001) (See figure on next page.) its protective effects in neuroinflammation-associated disease models or high toxicity conditions [81][82][83][84][85][86].…”

Surgically-induced brain injury: where are we now?

“…Though hematoma formation can be mitigated through proper surgical management, its formation can contribute the propagation of neurological deficits [45]. Microbleeds that occur in the periphery may not be as detrimental as a bleed that is in the brain because of the limited space for expansion.…”

“…In the following sections, we expand on the concept of preconditioning and propose the use of venom-derived proteins as a preconditioning therapy for SBI. [35,44,45,67,68], it has often been noted that clinical translation is limited since many injuries occur spontaneously. In the last few decades, the potential of PC, especially for scheduled (or elective) surgeries, has become a real focus in hopes of developing an effective therapy.…”

“…Venom activities including intravascular hemolysis, pulmonary congestion and edema, anticoagulation, and death are believed to be caused primarily by the PLA 2 isoforms. After Kim et al [45] and Wang et al [67,68] demonstrated that venoms with PLA 2 can attenuate brain edema and improve neurological outcomes, we became interested in investigating a pure PLA 2 therapy. Because of the complex nature of the venoms these investigators used, and also the presence of immunogenic proteins in these venoms, there is a need to study a PLA 2 -rich venom such as that of P. papuanus.…”

“…While preconditioning (PC) studies have demonstrated promising neuroprotective effects for several animal models of different forms of brain injury [ 35 , 44 , 45 , 67 , 68 ], it has often been noted that clinical translation is limited since many injuries occur spontaneously. In the last few decades, the potential of PC, especially for scheduled (or elective) surgeries, has become a real focus in hopes of developing an effective therapy.…”