Early administration of keratinocyte growth factor improves β-cell regeneration in rat with streptozotocin-induced diabetes

Abstract

The aim of our study was to investigate the ability of keratinocyte growth factor (KGF; palifermin) in regulating b-cell growth in normal newborn rats and in rats with neonatal diabetes. Wistar rats were injected with streptozotocin (STZ) to induce diabetes on the day of birth. From days 2 to 6 after birth, animals received a daily s.c. injection of KGF (STZ/KGF group) and at the dose of 3 mg/kg body weight or saline solution (STZ groups). A group of non-diabetic Wistar rats was treated either with saline (Wistar group) or with KGF from days 2 to 6 after birth at the dose of 3 mg/kg body weight (Wistar/KGF group). b-cell mass was measured at day 7 after birth in all groups. b-and ductal cells replication were measured in all groups and apoptosis was assessed in the pancreas of 2-, 4-, and 7-day-old STZ and STZ/KGF rats. The total b-cell mass of the 7-day-old KGF/STZ neonates was significantly increased compared with that of age-matched STZ rats. b-cell replication rate was decreased at day 2 in the STZ/KGF group and was similar in the 4-and 7-day-old rats from STZ and STZ/KGF groups. Duct cell replication was significantly increased in the pancreas of 2-and 4-day-old KGF/STZ neonates when compared with that of age-matched rats from STZ control group. The rate of apoptosis in the neonatal pancreases of STZ and KGF/STZ groups was not significantly different. In non-diabetic Wistar rats, KGF treatment led to a slight but significant increase in duct cell proliferation at day 2 without significant changes in the total b-cell mass in the 7-dayold rats. We provide evidence for a growth-promoting effect of KGF during b-cell regeneration in neonatal diabetic rats. KGF exerts strong mitogenic effect on the pancreatic duct cells, thus expanding the population of precursor cells that subsequently differentiate into insulin-producing b-cells.

Neonatal growth and regeneration of β-cells are regulated by the Wnt/β-catenin signaling in normal and diabetic rats

“…Since the number of ␤-cells is the result of the balance between new cell formation and cell death, we looked at apoptotic cells within the pancreases of our experimental groups. In all groups, and in line with our previous reports (35), the frequency of ␤-cell apoptosis as well as acinar and ductal cell apoptosis was extremely low in the pancreatic sections. In the four pancreases analyzed in each group, the percentages of apoptotic ␤-cells were 0.4 Ϯ 0.1, 0.3 Ϯ 0.1, and 0.5 Ϯ 0.05% in the pancreases of STZ/Std, STZ/GSK-3␤-AS, and STZ/LiCl, respectively.…”

“…We found no difference in the number of apoptotic ␤-cells between the age-matched animals of the two groups. As reported previously, the basal proportion of apoptosis in the pancreas of STZ neonates is extremely low (35). This could be explained partly by the fact that, in adult rats, STZ-induced apoptosis occurs within a few hours after STZ administration (34).…”

β-Cell regeneration: the pancreatic intrinsic faculty

“…Another EGF-like molecule, HB-EGF, also improves b-cell mass recovery by stimulating ductal b-cell neogenesis and b-cell proliferation [113]. Similar observations were made in STZ-treated newborn rats that received FGF-7 (fibroblast growth factor family) [114].…”

Diabetic GK/Par rat β-cells are spontaneously protected against H2O2-triggered apoptosis. A cAMP-dependent adaptive response

“…Freshly or 24-h-cultured islets were fixed in aqueous Bouin's solution (picric acid 71.4%, formaldehyde 23.8%, acetic acid 4.8%, all by volume; VWR International, Fontenay-sous-Bois, France) and embedded in paraplast, according to standard procedures. Immunohistochemistry was performed as previously described (50,53). Apoptotic cells in the islet sections were detected by TdT-dependent dUTP-biotin nick end labeling (TUNEL) assay using the ApopTag peroxidase in situ apoptosis detection kit (Chemicon International, Chandlers Ford, UK) according to the manufacturer's instructions.…”