*3.4. Histological Analysis of the Ileum and Liver*

The ileum in mice of the HLP-treated groups exhibited normal histological features (Figure 3a). The ileal villi lengths and crypt depths of all mouse groups were similar. However, the goblet cell numbers among the villi clearly increased in the ileum compared to those of the ND group. Goblet cells are one of the most distinct cell types in the

epithelium for intrinsic mucosal immunity and synthesize and secrete mucin, which forms a mucosal barrier to protect epithelial cells [35]. As shown in Figure 3b, the hepatocytes in the ND group were arranged in an orderly manner and were distributed radially around the hepatic cords. The liver tissue structures of the HLP-treated groups were normal and clearly showed the nucleolus, central veins, and abundant cytoplasm. This result implied that, from a pathological perspective, HLP administration would not cause hepatocellular injury.

**Figure 3.** Histological examination of the ileum (**a**) and liver (**b**) by H&E staining (200×).

#### *3.5. Effects of HLP on Oxidative Stress Parameters in Mouse Livers*

Oxidative stress, with excessive formation of reactive oxygen species (ROS), is a significant participant in diabetes and cardiovascular disease development and progression. High ROS levels damage cell structures and induce lipid peroxidation, which causes further injury to the surrounding tissues. Meanwhile, ROS also reduces antioxidant enzyme activities in the body, which results in further oxidative damage [36]. As important antioxidant enzymes in the defense system, both GSH-Px and SOD play crucial roles in protecting tissues against oxidative damage that is induced by superoxide anions [37]. GSH-Px catalyzes the formation of glutathione and reacts with ROS to decrease oxidant levels and lipid oxidation. SOD is the most strongly antioxidant enzyme in the first line of defense against ROS.

The GSH-Px activities in the livers of the HLP-H group were significantly higher (*p* < 0.05) than those of the ND group (Figure 4a). Although there were no differences (*p* > 0.05) in SOD activity among the various groups, the SOD activities in the livers of the HLP-M and HLP-H groups were slightly higher than those of the ND group (Figure 4b). The increasing GSH-Px and SOD levels in the liver indicated that high-dose HLP enhanced the antioxidant defense system's reaction to oxidative stress. MDA, a lipid peroxidation secondary product, is involved in forming lipid radicals and reflects the degree of cytotoxicity and cellular damage [38]. The liver MDA levels in the HLP-treated groups significantly declined compared with those in the ND group (Figure 4c). However, no significant differences were observed among the different HLP-treated groups in reducing the MDA levels (*p* > 0.05). This result indicated that HLP exhibited antioxidant activity by activating endogenous antioxidative enzymes.

**Figure 4.** Effects of HLP on GSH-Px activity (**a**), SOD activity (**b**), and MDA content (**c**) in the mouse livers. Values with different letters are significantly different (*p* < 0.05).
