Objective

2

To investigate the effects of compound

Lactobacillus acidophilus

tablets （CLAT） combined with Portulacae Herba extract （POE） on intestinal microbiota， immune function， and the cyclic adenosine monophosphate （cAMP）/protein kinase A （PKA） pathway in rats with eczema.

Methods

2

Fifty adult male SD rats were randomly divided into five groups （

n

=10 per group）： normal control， model， CLAT， POE， and combination （CLAT+POE） groups. Eczema models were established in all groups except the normal control group. After successful modeling， interventions were administered via gavage for 14 days： rats in the CLAT group received CLAT suspension， those in the POE g

roup received POE solution， those in the combination group received CLAT+POE， and rats in the normal control and model groups were given 0.9% NaCl solution. After intervention， the following assessments were conducted： ①skin lesions on the back and scratching frequency of rats； ②serum interferon-γ （IFN-γ） and interleukin-4 （IL-4） levels via enzyme-linked immunosorbent assay （ELISA）； ③intestinal microbiota abundance via 16S rRNA sequencing； ④histopathology of lesional skin via hematoxylin and eosin （HE） staining； ⑤ cAMP and PKA protein levels via Western blot.

Results

2

①The skin of normal group rats appeared light red， delicate， and smooth， with soft and clear skin texture. The back skin of model group rats showed obvious erythema， infiltration， scales， etc.， consistent with eczema modeling characteristics. Compared with the model group， skin lesions on the back of rats in the other treatment groups improved significantly， with the most prominent improvement in the combination group. The scratching frequency was decreased in the CLAT， POE， and combination groups compared with the model group （

P

<

0.05）， and was further reduced in the combination group compared with the CLAT or POE group （

P

<

0.05）. ②Compared with the normal group， the model group exhibited increased IL-4 levels and decreased IFN-γ levels （

P

<

0.05）. Compared with the model group， IL-4 levels were decreased and IFN-γ levels were increased in the CLAT and POE groups （

P

<

0.05）； moreover， the combination group showed lower IL-4 levels and higher IFN-γ levels than the CLAT or POE group （

P

<

0.05）. ③Model rats had higher

Firmicutes

abundance than normal rats； all treatment groups reduced

Firmicutes

， with the combination group showing the greatest efficacy. ④HE staining revealed that rats in the normal group had normal epidermal keratinization， and no edema or inflammatory cell infiltration was observe

d in the dermal papilla layer. In contrast， model group rats exhibited abnormal epidermal keratinization and abundant inflammatory cell infiltration， partially accompanied by fibrosis and vascular proliferation. In the CLAT， POE， and combination groups， inflammatory cells in the epidermis gradually disappeared， and skin structure gradually normalized； notably， the combination group showed only slight dermal inflammation and no edema， presenting the best pathological improvement. ⑤Compared with the normal group， cAMP and PKA protein levels were decreased in the model group （

P

<

0.05）. Compared with the model group， cAMP and PKA levels were increased in the CLAT group （

P

<

0.05）， further increased in the POE group compared with the CLAT group （

P

<

0.05）， and the combination group showed higher levels than the CLAT or POE group （

P

<

0.05）.

Conclusion

2

The combination of CLAT and POE alleviates eczema by modulating intestinal microbiota， restoring the T helper cell Th1/Th2 balance， and activating the cAMP/PKA pathway， thereby synergistically enhancing therapeutic effects.