Analysis of the Pathogenesis of Gram-Negative Bacterial Sepsis in Rats Under Nano-Body

This work aimed to evaluate the effectiveness of several anti-TLR4 nanobody administration techniques in a gram-negative bacterial sepsis (GNBS) rat model. The targeting proteins for TI-Nb2 and TC-Nb6 anti-TLR4 nanobodies were TLR4203-348 and TLR4349-582, respectively. The survival times (STs) of 44 Sprague-Dawley (SD) rats were tracked in the TI-Nb2, TC-Nb6, TI-Nb2+TC-Nb6, and D0 groups (saline control). Besides, the ELISA was utilized to measure the levels of TNF-, IL-1, IL-8, and IL-10 in different groups. An automatic biochemical analyzer was employed to determine the levels of AST, ALT, AMS, CRE, and Urea. Furthermore, the rat liver and kidney tissue samples were stained with hematoxylin-eosin (HE). Cleaved-caspase-3 (CC3) protein expression (PE) in rat tissues was discovered using immunohistochemistry, and the positive unit (PU) value was computed. The TI-Nb2+TC-Nb6 group exhibited a longder ST, lower TNF- α , IL-1 β , IL-8, ALT, AST, AMS, CRE, and Urea levels, and a smaller CC3 protein PU value in nucleus and cytoplasm than the TI-Nb2, TC-Nb6, and D0 groups (all P <0.05). The above findings indicated that the combined usage of TI-Nb2 and TC-Nb6 can successfully reduce the expression levels of CC3 protein, biochemical markers, and inflammatory factors. This could protect the liver, kidneys, and other organs and prolong the ST of sepsis rats.