Impact of lactobacillus probiotics on vaccine response in diabetic rats: modulation of inflammatory cytokines

Lymph nodes are essential for immune function as they contain immune cells that activate responses and filter pathogens from lymph. This study investigates how diabetes-related metabolic challenges affect immune function, focusing on the impact of Lactobacillus probiotics on lymph node responses to meningococcal vaccines in thirty male Albino rats with Streptozotocin-induced diabetes, established two weeks before vaccination. The diabetic rats were divided equally and randomly into three groups: one untreated (UD group), one receiving two shots of the meningococcal vaccine (DM group), and one receiving the same vaccination regimen alongside oral doses of <i>Lactobacillus rhamnosus</i> probiotics (DML group). We monitored the rats' weights and measured the expression levels of inflammatory cytokines (IL-1β, TNF-α, and IL-2) in their lymph nodes as markers of immune activation after vaccination. Diabetic rats vaccinated against meningococcal disease showed increased levels of IL-1β and TNF-α, which showed a significant reduction by <i>Lactobacillus</i> supplementation after three weeks. However, following the second vaccination, <i>Lactobacillus</i> significantly increased IL-1β and TNF-α levels. Also, <i>Lactobacillus</i> appeared to modulate the initial spike in IL-2, with a notable increase observed five weeks after the second vaccine dose. Notably, the vaccination protocol did not affect the body weight of the diabetic rats. These findings suggest that while the vaccine elevates inflammatory cytokine levels in the lymph nodes of diabetic rats, <i>Lactobacillus</i> may help mitigate these responses and regulate IL-2 levels, indicating its potential value in enhancing diabetes management, optimizing vaccine effectiveness, and addressing autoimmune issues in diabetic individuals.