Evaluasi Histopatologi Hepatosit Mencit setelah Pemberian Kandidat Vaksin Iradiasi Streptococcus agalactiae Berbasis Nanopartikel Kitosan

Abstract

Streptococcus agalactiae merupakan penyebab penting mastitis subklinis pada sapi. Penelitian ini mengevaluasi perubahan histopatologis hepatosit setelah pemberian kandidat vaksin S. agalactiae teriradiasi yang diformulasikan dengan trehalosa dan nanopartikel kitosan (VSaC) pada mencit. Sebanyak 20 mencit dibagi secara acak menjadi lima kelompok: kontrol phosphate-buffered saline, trehalosa, nanopartikel kitosan, kandidat vaksin teriradiasi, dan VSaC. Perlakuan diberikan secara intraperitoneal. Pada hari keempat, mencit dieutanasia dan jaringan hati diperiksa secara histopatologis. Apoptosis hepatosit ditemukan pada seluruh kelompok dengan jumlah bervariasi antarzona lobulus. Degenerasi hidropis ringan ditemukan secara tidak konsisten. Nekrosis, infiltrasi sel radang, dan kerusakan morfologi hati tidak ditemukan. VSaC tidak menunjukkan bukti hepatotoksisitas dan berpotensi dikembangkan sebagai kandidat vaksin untuk mencegah mastitis subklinis pada sapi.

Streptococcus agalactiae is an important cause of subclinical mastitis in cattle. This study evaluates the histopathological change of hepatocytes after the injection of an irradiated S. agalactiae vaccine candidate formulated with trehalose and chitosan nanoparticles (VSaC) in mice. Twenty mice were randomly assigned to five groups: phosphate-buffered saline control, trehalose, chitosan nanoparticles, irradiated vaccine candidate, and VSaC. Treatments were administered intraperitoneally. The mice were euthanized on the fourth day, and liver tissues were examined histopathologically. Hepatocyte apoptosis occurred in all groups, with variable numbers across lobular zones. Mild hydropic degeneration was inconsistently observed. No necrosis, inflammatory cell infiltration, or disruption of hepatic morphology were detected. Findings were comparable among groups. VSaC showed no evidence of hepatotoxicity and may be developed as a subclinical mastitis vaccine candidate in cattle.