Probiotic Intervention Mitigates Behavioural Effects of Maternal Morphine Exposure in Offspring

Recent research has highlighted the significant influence of the parental environment on offspring behaviour. Evidence suggests that parental exposure to morphine, even before conception, can have long-lasting adverse effects on offspring phenotypes. Finding noninvasive ways to mitigate these effects is crucial, as the mental health of offspring is of great importance. This study explored the impact of maternal administration of Bifidobacterium longum and Bacteroides fragilis during morphine exposure on male and female offspring. Adult female Wistar rats were exposed to morphine (n = 24) or saline (n = 24) for 10 days. Within each group, the rats were treated with oral saline (n = 8), B. longum (n = 8) or B. fragilis (n = 8) during the morphine or saline treatments. Ten days after the last treatment, the females mated with drug-naïve males, and their adult male and female offspring underwent behavioural assessments for depressive-like behaviour, nociception, memory and compulsive-like behaviour. The findings revealed that both B. longum and B. fragilis restored memory impairment and changes in nociception induced by maternal morphine exposure in male and female offspring. However, B. fragilis did not affect the enhancement of compulsive-like behaviour caused by maternal morphine exposure. In saline-treated female offspring, administration of these probiotics increased the number of buried marbles, which serve as an index for compulsive behaviour. Regarding depressive-like behaviour, maternal morphine exposure increased depressive-like behaviour in the offspring. B. longum was ineffective in reducing depressive-like behaviour in female offspring but significantly alleviated it in male offspring of morphine-exposed dams. In conclusion, the beneficial effects of administering B. longum and B. fragilis to dams during morphine exposure may be due to the direct impact of these probiotics on the mothers, reducing the side effects of morphine or potentially through other mechanisms. Further investigation is needed to clarify these mechanisms.