Abstract
Introduction: The American Cancer Society estimated that more than 1 million new cancer cases were diagnosed in 2005 and a majority of these patients died from metastatic spread. The standard for treating solid tumor cancer is surgical resection. However, it has been suggested that surgical resection may, in fact, promote metastasis. One of the body's natural defenses to combat metastasis is the activity of natural killer (NK) cells. NK cells serve as a vital mediator of detection during the early innate immune response and destruction of aberrant cells. It has been demonstrated that benzodiazepines may ameliorate surgery-induced suppression of NK cell activity. We examined the effect of a 14-day course of valerian, a herbal anxiolytic, on NK cell activity in Sprague-Dawley rats.
Methods: Thirty-five rats were assigned to 1 of 3 groups: (1) surgical animals administered research grade valerian, 15 mg/kg solubilized in peanut oil; (2) surgical animals administered peanut oil (vehicle); and (3) anesthesia-only animals administered valerian. One day before the 14-day course of valerian, blood was drawn to assay baseline NK cell activity. On experimental day, all animals were administered isoflurane anesthesia. Surgical animals underwent a standard laparotomy whereas anesthesia-only rats were anesthetized for the same period of time as the surgical rats. Twenty-four hours postexperiment animals underwent a second blood draw to assay NK cell activity.
Results: Analysis of covariance (ANCOVA) was used to analyze NK cell activity (measured in lytic units). Our results suggested that there was no difference (P = .9) in suppression within or between groups.
Conclusions: Clinical studies with valerian have been published but with small numbers and some ambiguity. Further research regarding valerian's effectiveness as a modulator of NK cell activity and whether dosage or route of administration is a factor in modulation is still warranted.