Membrane Vesicles from Lactobacillus Acidophilus Reduce Intestinal Inflammation and Increase 5-HT in the Substantia...

This study aimed to investigate the role of membrane vesicles (MVs) from the probiotic Lactobacillus acidophilus in reducing intestinal inflammation and increasing 5-hydroxytryptamine (5-HT) and tyrosine hydroxylase (TH) in the substantia nigra in the 6-hydroxydopamine (6-OHDA) rat model of Parkinson's disease (PD).

Twenty healthy male Wistar rats were randomly assigned to four groups (n = 5 per group), including a) control, b) 6-OHDA, c) 6-OHDA+MV, and d) sham groups. PD was induced by bilateral injection of 6-OHDA. Rats in the 6-OHDA+MV group received MV equivalent to 1 × 10⁷ colony-forming units (CFU)/mL 3 d/wk by oral gavage for 4 wk. At the end of 4 wk, all rats were sacrificed; the brain and small intestine were removed for cellular and molecular analysis.

The induction of PD by 6-OHDA induced a remarkable decrease in beam-walking (p <0.0001). In addition, the expression of protein and genes (receptor) of 5-HT (r-5-HT1A) decreased, and that of protein and gene (receptor; GABBR1) of GABA increased in the PD group (p <0.05 compared with the healthy control group), while MV gavage of 6-OHDA-injected rats controlled these factors in the substantia nigra. In the intestinal tissue, the expression of TLR-4 and α-synuclein gene was significantly increased in the 6-OHDA group compared to the control group (p <0.0001).

MVs might act as potential beneficial tools to reduce intestinal inflammation, control neurological damage associated with PD, and increase 5-HT neurotransmitters. It seems that MVs from L. acidophilus may have therapeutic potential in Parkinson's neurological disorder by controlling the gut-brain axis.