Transgenerational modification of hippocampus TNF- and S100B levels in the offspring of rats chronically exposed to morphine during adolescence

Background: TNF- and S100B are important signaling factors that are involved in many aberrant conditions of the brain. Chronic morphine exposure causes aberrant modifications in the brain. Objectives: We examined the consequences of chronic morphine consumption by parents before mating on hippocampus TNF- and S100B levels in the parents and their offspring. Methods: A total of 12 adult female and 12 adult male Wistar rats were used as parents. Each gender was divided randomly into two groups: control and morphine consumer. Morphine consumer groups received morphine sulfate dissolved in drinking water (0.4 mg/ml) for 60 days. Control groups received water. Thirty days before mating, morphine was replaced with water. All offspring also received water. The hippocampus of both parental and offspring groups was extracted to measure TNF- and S100B levels using an ELISA. Results: Hippocampus TNF- levels were significantly increased due to chronic morphine use in both male and female parents compared to those of control parents (P < 0.01). Moreover, both male and female offspring of morphine-exposed parents showed a significant increase in hippocampus TNF- levels compared to those of control offspring (P < 0.01). Hippocampus levels of S100B were significantly decreased in male (P < 0.05) but not female morphine consumer parents relative to control parents. Both male and female offspring of morphine-exposed parents showed significant decreases in hippocampus S100B levels (P < 0.05) compared to those of control offspring. Conclusions: The consequences of chronic morphine use by parents, even when it is stopped long before mating and pregnancy, could induce modifications in the hippocampus of the next generation.