The immunomodulatory effect of oral NaHCO3 is mediated by the splenic nerve: multivariate impact revealed by artificial neural networks.

Stimulation of the inflammatory reflex (IR) is a promising strategy for treating systemic inflammatory disorders. Recent studies suggest oral sodium bicarbonate (NaHCO3) as a potential activator of the IR, offering a safe and cost-effective treatment approach. However, the mechanisms underlying NaHCO3-induced anti-inflammatory effects remain unclear. We investigated whether oral NaHCO3's immunomodulatory effects are mediated by the splenic nerve. Female rats received NaHCO3 or water (H2O) for four days, and splenic immune markers were assessed using flow cytometry. NaHCO3 led to a significant increase (p < 0.05, and/or partial eta squared > 0.06) in anti-inflammatory markers, including CD11bc + CD206 + (M2-like) macrophages, CD3 + CD4 + FoxP3 + cells (Tregs), and Tregs/M1-like ratio. Conversely, proinflammatory markers, such as CD11bc + CD38 + TNFα + (M1-like) macrophages, M1-like/M2-like ratio, and SSChigh/SSClow ratio of FSChighCD11bc + cells, decreased in the spleen following NaHCO3 administration. These effects were abolished in spleen-denervated rats, suggesting the necessity of the splenic nerve in mediating NaHCO3-induced immunomodulation. Artificial neural networks accurately classified NaHCO3 and H2O treatment in sham rats but failed in spleen-denervated rats, highlighting the splenic nerve's critical role. Additionally, spleen denervation independently influenced Tregs, M2-like macrophages, Tregs/M1-like ratio, and CD11bc + CD38 + cells, indicating distinct effects from both surgery and treatment. Principal component analysis (PCA) further supported the separate effects. Our findings suggest that the splenic nerve transmits oral NaHCO3-induced immunomodulatory changes to the spleen, emphasizing NaHCO3's potential as an IR activator with therapeutic implications for a wide spectrum of systemic inflammatory conditions.

Standardization of a novel blood-sampling method through the jugular vein for use in the quantified [14C] 2-deoxyglucose method.

In the traditional [14C] deoxyglucose (2DG) method for the measurement of local cerebral glucose utilization (LCGU), blood samples are collected from the femoral artery. However, the placement of a femoral catheter can affect locomotor activity of the animal. We wanted to develop a new technique for blood sampling that would not interfere with the ongoing behavior. Therefore, the present report establishes a method of collecting blood samples for the 2DG method through the jugular vein. To calibrate this method, catheters were inserted in both the femoral artery and jugular vein of adult male Sprague Dawley rats. The next day, rats were injected with 2DG (125 microCi/kg) through the jugular vein. To quantify 14C in plasma, the standard method of blood collection was used for the femoral artery while syringes were used to extract blood samples from the jugular vein. We calculated the integrated specific activity of the plasma and final tissue 2DG concentrations based on Sokoloff's original equation using blood samples derived from both vessels. LCGU determined in selected brain regions was equivalent using both sampling methods. In conclusion, sampling from the jugular vein is appropriate for the quantified 2DG method and does not disrupt locomotor activity of the rat.