Picrorhiza kurroa Enhances ß-Cell Mass Proliferation and Insulin Secretion in Streptozotocin Evoked ß-Cell Damage in Rats.

Autoimmune destruction of insulin producing pancreatic ß-cells leads to insulin insufficiency and hyperglycemia in type 1 diabetes mellitus. Regeneration of ß-cells is one of the proposed treatment for type 1 diabetes and insulin insufficiency. Picrorhiza kurroa is a medicinal herb and is traditionally being used for the treatment of various diseases. Previous studies reported the hypoglycemic potential of P. kurroa. However, its potential role in ß-cell induction in insulin secretion have not been fully investigated. Here, we characterized the hydro alcoholic extract of P. kurroa rhizome (PKRE) and further studied its ß-cell regeneration and induction of insulin secretion potential in streptozotocin (STZ) induced diabetic rats as well as in insulin producing Rin5f cells. 1H-NMR revealed the presence of more than thirty metabolites including picroside I and II in PKRE. Further, we found that PKRE treatment (100 and 200 mg/kg dose for 30 days) significantly (p ≤ 0.05) protected the pancreatic ß-cells against streptozotocin (STZ) evoked damage and inhibited the glucagon receptor expression (Gcgr) in hepatic and renal tissues. It significantly (p ≤ 0.05) enhanced the insulin expression and aids in proliferation of insulin producing Rin5f cells with elevated insulin secretion. Furthermore it significantly (p ≤ 0.05) increased insulin mediated glucose uptake in 3T3L1 and L6 cells. On the contrary, in diabetic rats, PKRE significantly (p ≤ 0.05) decreased high blood glucose and restored the normal levels of serum biochemicals. Altogether, our results showed that PKRE displayed ß-cell regeneration with enhanced insulin production and antihyperglycemic effects. PKRE also improves hepatic and renal functions against oxidative damage.

Taurine Increases Insulin Expression in STZ-Treated Rat Islet Cells In Vitro.

This research aims at figure out the effects and the pathway of taurine on insulin in islet cells cultured in vitro treated by STZ. In the experiment, islet cells were isolated from pancreatic tissue by in situ perfusion with collagenase V. The pancreatic islet cells, maintained in RPMI 1640 culture medium were divided into six groups: C: control, E: supplemented with 10 mmol/L of taurine, group M, T1, T2 and T3 was treated with STZ (0.5 mmol/L), at the same time, taurine were added in group T1,T2 and T3 for 30 min, and then culture medium were collected by centrifugation and then insulin levels were detected by radioimmunoassay, the cells were then rinsed with Hanks, and 0,10, 0, 5, 10, 20 mmol/L of taurine in group C, E, M, T1, T2 and T3 were added for 24 h respectively. Total RNA was extracted, then insulin gene and its transcription regulator such as PDX-1, NeuroD1 were amplified by semi-quantitative RT-PCR. The results showed that, the release of insulin from islet cells treated by STZ could be inhibited by taurine, gene expression of insulin, PDX-1 and NeuroD1 in STZ group decreased significantly, which were up-regulated by taurine administration. In conclusion, taurine exerts a certain degree of protective and reconstructive effects on islet cells treated by STZ.